Comparison of File Systems

Comparison of file systems 1

Comparison of file systemsThe following tables compare general and technical information for a number of file systems.

General information

File system Creator Yearintroduced

Original operating system

DECtape DEC 1964 PDP-6 Monitor

Level-D DEC 1968 TOPS-10

George 2 ICT (later ICL) 1968 George 2

V6FS Bell Labs 1972 Version 6 Unix

ODS-1 DEC 1972 RSX-11

RT-11 file system DEC 1973 RT-11

DOS (GEC) GEC 1973 Core Operating System

CP/M file system Gary Kildall 1974 CP/M

OS4000 GEC 1977 OS4000

FAT (8-bit) Marc McDonald, Microsoft 1977 Microsoft Disk BASIC

DOS 3.x Apple Computer 1978 Apple DOS

Pascal Apple Computer 1978 Apple Pascal

CBM DOS Commodore 1978 Microsoft BASIC (for CBM PET)

V7FS Bell Labs 1979 Version 7 Unix

ODS-2 DEC 1979 OpenVMS

FAT12 Tim Paterson 1980 QDOS, 86-DOS

AFS Carnegie Mellon University 1982 Multiplatform MultoOS

DFS Acorn Computers Ltd 1982 Acorn BBC Micro MOS

ADFS Acorn Computers Ltd 1983 Acorn Electron (later Arthur RISC OS)

FFS Kirk McKusick 1983 4.2BSD

ProDOS Apple Computer 1983 ProDOS 8

MFS Apple Computer 1984 Mac OS

FAT16 Microsoft 1984 MS-DOS 3.0

Elektronika BK tapeformat

NPO "Scientific centre" (nowSitronics)

1985 Vilnius Basic, BK monitor program

HFS Apple Computer 1985 Mac OS

Amiga OFS[1] Metacomco for Commodore 1985 Amiga OS

High Sierra Ecma International 1985 MS-DOS, Mac OS

NWFS Novell 1985 NetWare 286

FAT16B Compaq 1987 Compaq MS-DOS 3.31, DR DOS 3.31

MINIX V1 FS Andrew S. Tanenbaum 1987 MINIX 1.0

Amiga FFS Commodore 1988 Amiga OS 1.3

Comparison of file systems 2

HPFS IBM & Microsoft 1988 OS/2

ISO 9660:1988 Ecma International, Microsoft 1988 MS-DOS, Mac OS, and AmigaOS

JFS1 IBM 1990 AIX[2]

VxFS VERITAS, (now Symantec) 1991 AIX, HP-UX, Solaris, Linux

ext Rémy Card 1992 Linux

WAFL NetApp 1992 Data ONTAP

MINIX V2 FS Andrew S. Tanenbaum 1992 MINIX 1.6 and 2.0

AdvFS DEC 1993[3] Digital Unix

NTFS Version 1.0 Microsoft, Tom Miller, GaryKimura

1993 Windows NT 3.1

LFS Margo Seltzer 1993 Berkeley Sprite

ext2 Rémy Card 1993 Linux, Hurd

UFS1 Kirk McKusick 1994 4.4BSD

XFS SGI 1994 IRIX, Linux, FreeBSD

HFS (Hierarchical FileSystem)

IBM 1994 MVS/ESA (now z/OS)

Rock Ridge Young Minds Inc. 1994 Linux, Mac OS, Amiga OS, and FreeBSD

Joliet ("CDFS") Microsoft 1995 Microsoft Windows, Linux, Mac OS, andFreeBSD

PFS Michiel Pelt 1996 AmigaOS

Romeo Adaptec 1996 Microsoft Windows

UDF ISO/ECMA/OSTA 1995 -

FAT32 Microsoft 1996 Windows 95b[4]

QFS LSC Inc, Sun Microsystems 1996 Solaris

GPFS IBM 1996 AIX, Linux, Windows

Be File System Be Inc., D. Giampaolo, C.Meurillon

1996 BeOS

HFS Plus Apple Computer 1998 Mac OS 8.1

NSS Novell 1998 NetWare 5

PolyServe File System(PSFS)

PolyServe 1998 Windows, Linux

ODS-5 DEC 1998 OpenVMS 7.2

SFS John Hendrikx 1998 AmigaOS, AROS, MorphOS

ext3 Stephen Tweedie 1999 Linux

ISO 9660:1999 Ecma International, Microsoft 1999 Microsoft Windows, Linux, Mac OS X,FreeBSD, and AmigaOS

JFS IBM 1999 OS/2 Warp Server for e-business

GFS Sistina (Red Hat) 2000 Linux

Melio FS Sanbolic 2001 Windows

NTFS Version 3.1 Microsoft 2001 Windows XP

ReiserFS Namesys 2001 Linux

Comparison of file systems 3

zFS IBM 2001 z/OS (backported to OS/390)

FATX Microsoft 2002 Xbox

UFS2 Kirk McKusick 2002 FreeBSD 5.0

Lustre Cluster File Systems (later OracleCorporation)

2002 Linux

OCFS Oracle Corporation 2002 Linux

VMFS2 VMware 2002 VMware ESX Server 2.0

ext3cow Zachary Peterson 2003 Linux

Fossil Bell Labs 2003 Plan 9 from Bell Labs 4

Google File System Google 2003 Linux

PramFS MontaVista 2003 Linux

Reliance[5] Datalight 2003 Windows CE, VxWorks, custom ports

VxCFS VERITAS, (now Symantec) 2004 AIX, HP-UX, Solaris, Linux

ZFS Sun Microsystems 2004 Solaris, FreeBSD, PC-BSD, FreeNAS

Reiser4 Namesys 2004 Linux

Non-Volatile FileSystem

Palm, Inc. 2004 Palm OS Garnet

MINIX V3 FS Andrew S. Tanenbaum 2005 MINIX 3

OCFS2 Oracle Corporation 2005 Linux

NILFS NTT 2005 Linux, (ReadOnly for NetBSD)

VMFS3 VMware 2005 VMware ESX Server 3.0

GFS2 Red Hat 2006 Linux

ext4 Various 2006 Linux

exFAT Microsoft 2006, 2009 Windows CE 6.0, Windows XP SP3,Windows Vista SP1

TexFAT/TFAT Microsoft 2006 Windows CE 6.0

Btrfs Oracle Corporation 2007 Linux

HAMMER Matthew Dillon 2008 Dragonfly BSD

Tux3 Various 2008 Linux

UBIFS Nokia with help of University ofSzeged

2008 Linux

Oracle ACFS Oracle Corporation 2009 Linux - Red Hat Enterprise Linux 5 andOracle Enterprise Linux 5 only

Reliance Nitro[5] Datalight 2009 Windows CE, Windows Mobile, VxWorks,Linux, custom ports

LTFS IBM 2010 Linux, Mac OS X, planned MicrosoftWindows,

IlesfayFS Ilesfay Technology Group 2011 Microsoft Windows, planned Red HatEnterprise Linux

VMFS5 VMware 2011 VMware ESXi 5.0tux 3 stats

ReFS Microsoft 2012, 2013 Windows 2012 Server

Lanyard Filesystem Dan Luedtke 2012 Linux

Comparison of file systems 4

F2FS Samsung 2012 Linux

File system Creator Yearintroduced

Original operating system

Limits

File system Maximumfilename length

Allowablecharacters in

directory entries[6]

Maximum pathname length Maximum filesize

Maximumvolume size

[7]

AcornADFS

10 bytes Any ISO 8859-1character except:

SPACE $ & % @ \ ^: . # * " ¦

No limit defined 512 MB or4 GB[8]

512 MB or4 GB[9]

Apple DOS3.x

30 bytes Any byte exceptNUL

30 B, no subdirectories (105 files per disk)

Unknown

113.75 kB DOS3.1, 3.2

140 kB DOS 3.3(assuming

standard 35tracks)

AppleProDOS

15 bytes A-Z, a-z, 0-9, andperiod

Unknown16 MB 32 MB

CP/M filesystem

8.3 any byte except:SPACE < > . , ; : = ?

* [ ] % | ( ) / \[10]

16 "user areas", no subdirectories 8 MB[] 8 MB to512 MB[]

IBM SFS 8.8 Unknown Non-hierarchical[11] Unknown Unknown

DECtape 6.3 A–Z, 0–9 DTxN:FILNAM.EXT = 15 369,280 B (577 *640)

369,920 B (578 *640)

ElektronikaBK tapeformat

16 bytes

Unknown

Non-hierarchical 64 kB Not limited.Approx. 800 kB(one side) for 90

min cassette

MicroDOSfile system

14 bytesUnknown Unknown

16 MB 32 MB

Level-D 6.3 A–Z, 0–9 DEVICE:FILNAM.EXT[PROJCT,PROGRM]= 7 + 10 + 15 = 32; + 5*7 for SFDs = 67

24 GB(34,359,738,368words (235-1);

206,158,430,208SIXBIT bytes)

12 GB (approx;64 * 178 MB)

RT-11 6.3 A–Z, 0–9, $ Non-hierarchical 32 MB (65536 *512)

32 MB

V6FS 14 bytes[12] Any byte exceptNUL and /[13]

No limit defined[14] 16 MB[15] 2 TB

DOS (GEC) 8 bytes A–Z, 0–9 Non-hierarchical 64 MB 64 MB

OS4000 8 bytes A–Z, 0–9Period is directory

separator

No limit defined[14] 2 GB 1 GB (at least)

CBM DOS 16 bytes Any byte exceptNUL

Non-hierarchical 16 MB 16 MB

Comparison of file systems 5

V7FS 14 bytes[12] Any byte exceptNUL and /[13]

No limit defined[14] 1 GB[16] 2 TB

exFAT 255 characters[17] Any Unicode exceptNUL

No limit defined 127 PB 64 ZB, 512 TBrecommended[]

TexFAT 247 characters Any Unicode exceptNUL

No limit defined 2 GB 500 GB Tested[]

FAT12 8.3 (255 UTF-16code units with

LFN)[12]

Any byte except forvalues 0-31, 127

(DEL) and: " * / : <> ? \ | + , . ; = [](lowcase a-z are

stored as A-Z). WithVFAT LFN anyUnicode exceptNUL[12][13]

No limit defined[14] 32 MB (256 MB) 32 MB (256 MB)

FAT16 8.3 (255 UTF-16code units with

LFN)[12]

Any byte except forvalues 0-31, 127

(DEL) and: " * / : <> ? \ | + , . ; = [](lowcase a-z are

stored as A-Z). WithVFAT LFN anyUnicode exceptNUL[12][13]

No limit defined[14] 2 GB (4 GB) 2 GB or 4 GB

FAT32 8.3 (255 UTF-16code units with

LFN)[12]

Any byte except forvalues 0-31, 127

(DEL) and: " * / : <> ? \ | + , . ; = [](lowcase a-z are

stored as A-Z). WithVFAT LFN anyUnicode exceptNUL[12][13]

No limit defined[14] 4 GB(256 GB[18])

2 TB[19]

(16 TB)

FATX 42 bytes[12] ASCII. Unicode notpermitted.

No limit defined[14] 2 GB 2 GB

Fossil Unknown Unknown Unknown Unknown Unknown

MFS 255 bytes Any byte except : No path (flat filesystem) 226 MB 226 MB

HFS 31 bytes Any byte except:[20]

Unlimited 2 GB 2 TB

HPFS 255 bytes Any byte exceptNUL[21]

No limit defined[14] 2 GB 2 TB[22]

NTFS 255characters[23][][24]

Depends onnamespace

used[23][][24][25]

32,767 Unicode characters with each pathcomponent (directory or filename) commonly

up to 255 characters long[14]

16 EB[26] 16 EB[26]

Comparison of file systems 6

ReFS 255 unicodecharacters [27]

Unknown

32 kB 16 EB Format supports256ZB with

16kB cluster size(2^64 * 16 *

2^10). Windowsstack addressing

allows 16EB

HFS Plus 255 UTF-16 codeunits[28]

Any validUnicode[13][29]

Unlimited 8 EB 8 EB[][30]

FFS 255 bytes Any byte exceptNUL[13]

No limit defined[14] 8 ZB 8 ZB

UFS1 255 bytes Any byte exceptNUL[13]

No limit defined[14] 226 TB 226 TB

UFS2 255 bytes Any byte exceptNUL[13]

No limit defined[14] 32 PB 1 YB

ext2 255 bytes Any byte exceptNUL[13] and /

No limit defined[14] 2 TB[7] 32 TB

ext3 255 bytes Any byte exceptNUL[13] and /

No limit defined[14] 2 TB[7] 32 TB

ext3cow 255 bytes Any byte exceptNUL,[13] / and @

No limit defined[14] 2 TB[7] 32 TB

ext4 255 bytes Any byte exceptNUL[13] and /

No limit defined[14] 16 TB[7][] 1 EB[31]

Lustre 255 bytes Any byte exceptNUL[13] and /

No limit defined[14] 32 PB (on ext4) 1 YB (on ext4,20 PB tested)

GPFS 255 UTF-8codepoints

Any byte exceptNUL[13]

No limit defined[14] 512 YB 512 YB (4 PBtested)

GFS 255 Any byte exceptNUL[13]

No limit defined[14] 8 EB[32] 8 EB[32]

ReiserFS 4,032 bytes/226characters

Any byte exceptNUL[13]

No limit defined[14] 8 TB[33] (v3.6),2 GB (v3.5)

16 TB

NILFS 255 bytes Any byte exceptNUL[13]

No limit defined[14] 8 EB 8 EB

Reiser4 3,976 bytes Any byte except /and NUL

No limit defined[14] 8 TB on x86Unknown

OCFS 255 bytes Any byte exceptNUL[13]

No limit defined[14] 8 TB 8 TB

OCFS2 255 bytes Any byte exceptNUL[13]

No limit defined[14] 4 PB 4 PB

Reliance 260 bytes OS specific 260 B 4 GB 2 TB

RelianceNitro

1,024 bytes OS specific 1024 bytes 32 TB 32 TB

JFS1 255 bytes Any byte exceptNUL[13]

No limit defined[14] 8 EB 4 PB

Comparison of file systems 7

JFS 255 bytes Any Unicode exceptNUL

No limit defined[14] 4 PB 32 PB

QFS 255 bytes Any byte exceptNUL[13]

No limit defined[14] 16 EB[34] 4 PB[34]

BFS 255 bytes Any byte exceptNUL[13]

No limit defined[14] 260 GB[35] 2 EB

AdvFS 226 characters Any byte exceptNUL[13]

No limit defined[14] 16 TB 16 TB

NSS 226 characters Depends onnamespace used[36]

Only limited by client 8 TB 8 TB

NWFS 80 bytes[37] Depends onnamespace used[36]

No limit defined[14] 4 GB 1 TB

ODS-5 236 bytes[38] Unknown 4,096 bytes[39] 2 TB 2 TB

VxFS 255 bytes Any byte exceptNUL[13]

No limit defined[14] 256 TB 256 TB

UDF 255 bytes Any Unicode exceptNUL

1,023 bytes[40] 16 EB 2 TB (hard disk),8 TB (optical

disc)[41]

MINIX V1FS

14 or 30 bytes, setat filesystemcreation time

Any byte exceptNUL[13]

No limit defined[14] 64 MB[] 64 MB[]

MINIX V2FS

14 or 30 bytes, setat filesystemcreation time

Any byte exceptNUL[13]

No limit defined[14] 4 GB[] 1 GB, then 2TB[]

MINIX V3FS

60 bytes Any byte exceptNUL[13]

No limit defined[14] 4 GB 16 TB[]

VMFS2 128 Any byte exceptNUL and /[13]

2,048 4 TB[42] 64 TB

VMFS3 128 Any byte exceptNUL and /[13]

2,048 2 TB[42] 64 TB

ISO9660:1988

Level 1: 8.3,Level 2 & 3: ~ 180

Depends onLevel[43]

~ 180 bytes? 4 GB (Level 1 &2) to 8 TB (Level

3)[44]

8 TB[45]

Joliet("CDFS")

64 Unicodecharacters

All UCS-2 codeexcept * / \ : ; and

?[46]Unknown

4 GB (same asISO 9660:1988)

8 TB (same asISO 9660:1988)

ISO9660:1999

Unknown (207?) Unknown Unknown Unknown Unknown

High Sierra Unknown Unknown Unknown Unknown Unknown

HAMMER Unknown Unknown Unknown Unknown 1 EB

LTFS Unknown Unknown Unknown Unknown Unknown

PramFS 31 bytes Any byte exceptNUL

Unknown1 GB 8 EB

Comparison of file systems 8

LanyardFilesystem

255 bytes Any byte exceptNUL and /[13]

No limit defined 64 ZB 128 kB to64 ZB[47]

LEAN 4,068 bytes[48] case sensitive, inUTF-8 (any Unicode

codepoint)

No limit defined 8 EB 8 EB

XFS 255 bytes[49] Any byte exceptNUL[13]

No limit defined[14] 8 EB[50] 8 EB[50]

ZFS 255 bytes Any Unicode exceptNUL

No limit defined[14] 16 EB 16 EB

Btrfs 255 bytes Any byte exceptNUL

Unknown16 EB 16 EB

File system Maximumfilename length

Allowablecharacters in

directory entries[6]

Maximum pathname length Maximum filesize

Maximumvolume size

[7]

Metadata

File system Storesfile

owner

POSIX filepermissions

Creationtimestamps

Lastaccess/read

timestamps

Last contentmodificationtimestamps

Diskcopy

created

Lastmetadatachange

timestamps

Lastarchive

timestamps

Accesscontrol

lists

Security/MAClabels

Extendedattributes/Alternate

datastreams/

forks

Checksum/ECC

MaxTimestampGranularity

CBM DOS No No No No No No No No No No No No Unknown

CP/M filesystem

No No Yes[51] No Unknown Unknown No No No No No No Unknown

DECtape No No Yes No Unknown Unknown No No No No No No Unknown

ElektronikaBK tapeformat

No No No No Unknown Unknown No No No No No Yes Unknown

Level-D Yes Yes Yes Yes Unknown Unknown Yes Yes Yes No No No Unknown

RT-11 No No Yes No No No No No No No No No Unknown

DOS(GEC)

Yes No Yes Yes Yes Unknown No No No No No No Unknown

OS4000 Yes No Yes Yes Yes Unknown No No No No No No Unknown

V6FS Yes Yes No Yes Yes Unknown Yes No No No No No Unknown

V7FS Yes Yes No Yes Yes Unknown Yes No No No No No Unknown

FAT12No[52] No[53] Partial[54] Partial[54] Yes Yes No[55] No No No No[56] No

10milliseconds

FAT16No[52] No[53] Partial[54] Partial[54] Yes Yes No[55] No No No No[56] No

10milliseconds

FAT32No No Partial[54] Partial[54] Yes Yes No[55] No No No No No

10milliseconds

exFATNo No Yes Yes Yes No Unknown No No Unknown Unknown Partial

10milliseconds

HPFS Yes[57] No Yes Yes Yes Unknown No No No Unknown Yes No Unknown

Comparison of file systems 9

NTFSYes Yes[58] Yes Yes Yes No Yes No Yes Yes[59] Yes No

100nanoseconds

HFS No No Yes No Yes No No Yes No No Yes No Unknown

HFS Plus Yes Yes Yes Yes Yes No Yes Yes Yes Yes[60] Yes No 1 second

FFS Yes Yes No Yes Yes Unknown Yes No No No No No Unknown

UFS1 Yes Yes No Yes Yes Unknown Yes No Yes[61] Yes[61] No[62] No Unknown

UFS2 Yes Yes Yes Yes Yes Unknown Yes No Yes[61] Yes[61] Yes No Unknown

LFS Yes Yes No Yes Yes Unknown Yes No No No No No Unknown

ext2 Yes Yes No Yes Yes Unknown Yes No Yes[63] Yes[63] Yes No 1 second

ext3 Yes Yes No Yes Yes No Yes No Yes[63] Yes[63] Yes No 1 second

ext3cow Yes Yes No Yes Yes No Yes No Yes[63] Yes[63] Yes No 1 second

ext4Yes Yes Yes Yes Yes Unknown Yes No Yes[63] Yes[63] Yes Partial[64] 1

nanosecond

Lustre Yes Yes Partial[65] Yes Yes No Yes No Yes Yes Yes Partial[66][67] Unknown

GPFS Yes Yes Yes Yes Yes Unknown Yes No Yes Yes Yes Yes Unknown

GFS Yes Yes No Yes Unknown Unknown Yes No Yes[63] Yes[63] Yes No Unknown

NILFS Yes Yes Yes No Unknown Unknown Yes No Planned No Planned Yes Unknown

ReiserFS Yes Yes No Yes Yes No No No No No No No Unknown

Reiser4 Yes Yes No Yes Yes Unknown Yes No No No No No Unknown

OCFS No Yes No No Unknown Unknown Yes Yes No No No No Unknown

OCFS2 Yes Yes No Yes Unknown Unknown Yes No Yes No Yes Partial[68] Unknown

Reliance No No Yes No Yes No No No No No No Partial[69] Unknown

RelianceNitro

Linuxport

Linux port Yes Yes Yes No No NoLinuxport

No Yes Partial[69] Unknown

XFSYes Yes No Yes Yes Unknown Yes No Yes Yes[63] Yes No

1nanosecond

JFS Yes Yes Yes Yes Yes Unknown Yes No Yes Yes Yes No Unknown

QFS Yes Yes Yes Yes Unknown Unknown Yes Yes Yes No Yes No Unknown

BFS Yes Yes Yes No Unknown Unknown No No No No Yes No Unknown

AdvFS Yes Yes No Yes Yes Unknown Yes No Yes No Yes No Unknown

NSS Yes Yes Yes[70] Yes[70] Unknown Unknown Yes Yes[70] Yes Unknown Yes[71][72] No Unknown

NWFS Yes Unknown Yes[70] Yes[70] Unknown Unknown Yes Yes[70] Yes Unknown Yes[71][72] No Unknown

ODS-5 Yes Yes Yes Unknown Unknown Unknown Unknown Yes Yes Unknown Yes[73] No Unknown

VxFS Yes Yes Yes Yes Yes Unknown Yes No Yes Unknown Yes[63] No Unknown

UDF Yes Yes Yes Yes Unknown Unknown Yes Yes Yes No Yes No Unknown

Fossil Yes Yes[74] No Yes Unknown Unknown Yes No No No No No Unknown

ZFS Yes Yes Yes Yes Yes Unknown Yes Yes Yes Yes[75] Yes[76] Yes Unknown

Comparison of file systems 10

VMFS2 Yes Yes No Yes Unknown Unknown Yes No No No No No Unknown

VMFS3 Yes Yes No Yes Unknown Unknown Yes No No No No No Unknown

ISO9660:1988

No No Yes[77] No[78] Yes[79] Unknown No No No No No No Unknown

Joliet("CDFS")

No No Yes[77] No[78] Yes[79] Unknown No No No No No No Unknown

ISO9660:1999

No No Yes No Unknown Unknown No No No No No No Unknown

High Sierra No No Yes No Unknown Unknown No No No No No No Unknown

BtrfsYes Yes Yes Yes Yes Unknown Yes Unknown Yes Yes Yes Yes

1nanosecond

LanyardFilesystem

No No Yes No Yes No Yes No No No No No1

nanosecond

PramFS Yes Yes No Yes Yes Unknown Yes No Yes Yes Yes Yes 1 second

File system Storesfile

owner

POSIX filepermissions

Creationtimestamps

Lastaccess/readtimestamps

Last contentmodificationtimestamps

Diskcopy

created

Lastmetadatachange

timestamps

Lastarchive

timestamps

Accesscontrol

lists

Security/MAClabels

Extendedattributes/Alternate

datastreams/

forks

Checksum/ECC

MaxTimestampGranularity

Features

File

system

Hard

links

Symbolic

links

Block

journaling

Metadata-only

journaling

Case-sensitive Case-preserving File

Change

Log

Snapshot XIP Encryption COW integrated

LVM

Data

deduplication

Volumes are

resizeable

Lanyard

Filesystem No No No No Yes Yes No No No No No No NoOffline

(cannot beshrunk)

CBM DOS No No No No Yes Yes No No No No No No No No

CP/M file

systemNo No No No No No No No No No No No No Unknown

DECtape No No No No No No No No No No No No No Unknown

Level-D No No No No No No No No No No Unknown Unknown Unknown Unknown

RT-11 No No No No No No No No No No No No No Unknown

DOS

(GEC)No No No No No No No No No No No No No Unknown

OS4000 No Yes[80] No No No No No No No No No No No Unknown

V6FS Yes No No No Yes Yes No No No No No No No Unknown

V7FS Yes No[81] No No Yes Yes No No No No No No No Unknown

FAT12 No No No No No Partial No No No No No No No Offline[]

FAT16 No No No No No Partial No No No No No No No Offline[]

FAT32 No No No No No Partial No No No No No No No Offline[]

exFAT No No Unknown No No Yes No Unknown Unknown No Unknown Unknown Unknown Unknown

Comparison of file systems 11

GFS Yes Yes[82] Yes Yes[83] Yes Yes No No No No Unknown Unknown Unknown Online

GPFS Yes Yes Unknown Unknown Yes Yes Yes Yes Yes No Yes Yes No Online

HAMMER Yes Yes Unknown Unknown Yes Yes Unknown Yes Unknown Unknown Unknown Unknown On demand Unknown

HPFS No No No No No Yes No Unknown No No Unknown Unknown No Unknown

NTFSYes Yes[84] No[85] Yes[85] Yes[86] Yes Yes Partial[87] Yes Yes Partial Unknown Yes (Windows

Server 2012)[] Online[]

HFS No Yes[88] No No No Yes No No No No No No No Unknown

HFS Plus Yes[89] Yes No Yes[90] Partial[91] Yes Yes[92] No No Yes[93] No No No Yes[94]

FFS

Yes Yes No No[95] Yes Yes No No No No No No NoOffline

(cannot beshrunk)[96]

UFS1 Yes Yes No No Yes Yes No No No No No No No Unknown

UFS2

Yes Yes No No[97][98] Yes Yes No Yes Unknown No No No NoOffline

(cannot beshrunk)[99]

LFS Yes Yes Yes[100] No Yes Yes No No No No Unknown Unknown Unknown Unknown

ext2 Yes Yes No No Yes Yes No No Yes[101] No No No No Online[102]

ext3 Yes Yes Yes[103] Yes Yes Yes No No Yes Yes No No No Online[102]

ext3cow Yes Yes Yes[103] Yes Yes Yes Unknown Yes Unknown Yes Yes No No Unknown

ext4 Yes Yes Yes[103] Yes Yes Yes No No Yes Yes No No No Online[102]

Lustre

Yes Yes Yes[103] Yes Yes YesYes in2.0 and

laterNo[67] No No No[67] No[67] No[67] Online[104]

NILFS

Yes Yes Yes[100] No Yes Yes Yes Yes No No Yes Unknown Unknown

Online (sinceLinux-3.x

andnilfs-utils

2.1)

ReiserFS Yes Yes No[105] Yes Yes Yes No No No No No No No Online

Reiser4

Yes Yes Yes No Yes Yes No Unknown No Yes[106] Yes No Unknown

Online (canonly beshrunkoffline)

OCFS No Yes No No Yes Yes No No No No Unknown Unknown Unknown Unknown

OCFS2

Yes Yes Yes Yes Yes Yes No Partial[107] No No Unknown No NoOnline forversion 1.4and higher

Reliance No No No[108] No No Yes No No No No Yes No No Unknown

Reliance

NitroYes Yes No[108] No

Depends onOS

Yes No No No No Yes No No Unknown

XFS

Yes Yes Yes Yes Yes[109] Yes No No No No No No NoOnline

(cannot beshrunk)

Comparison of file systems 12

JFS

Yes Yes No Yes Yes[110] Yes No Yes No No No Unknown UnknownOnline

(cannot beshrunk)[111]

QFS Yes Yes No Yes Yes Yes No No No No Unknown Unknown Unknown Unknown

Be File

SystemYes Yes No Yes Yes Yes Unknown No No No No No No Unknown

NSS Yes Yes Unknown Yes Yes[112] Yes[112] Yes[113] Yes No Yes Unknown Unknown Unknown Unknown

NWFS Yes[114] Yes[114] No No Yes[112] Yes[112] Yes[113] Unknown No No No Yes[115] Unknown Unknown

ODS-2 Yes Yes[116] No Yes No No Yes Yes No No Unknown Unknown Unknown Unknown

ODS-5 Yes Yes[116] No Yes No Yes Yes Yes Unknown No Unknown Unknown Unknown Unknown

UDF Yes Yes Yes[100] Yes[100] Yes Yes No No Yes No No No No Unknown

VxFS Yes Yes Yes No Yes Yes Yes Yes[117] Unknown No Unknown Unknown Yes Unknown

Fossil No No No No Yes Yes Yes Yes No No Unknown No Yes[118] Unknown

ZFS

Yes Yes Yes[119] No[119] Yes Yes No Yes No Yes Yes Yes YesOnline

(cannot beshrunk)[120]

VMFS2 Yes Yes No Yes Yes Yes No No No No Unknown Unknown Unknown Unknown

VMFS3 Yes Yes No Yes Yes Yes No No No No Unknown Unknown Unknown Unknown

Btrfs Yes Yes No No Yes Yes Yes Yes No Planned[] Yes Yes Work-in-Progress Online

PramFS No Yes No No Yes Yes No No Yes No No No No No

File

system

Hard

links

Symbolic

links

Block

journaling

Metadata-only

journaling

Case-sensitive Case-preserving File

Change

Log

Snapshotting XIP Encryption COW integrated

LVM

Data

deduplication

Volumes are

resizeable

Allocation and layout policies

File system Block suballocation Variable file block size[121] Extents Allocate-on-flush Sparse files Transparent compression

CBM DOS No Partial[122] No No No No

CP/M filesystem No No Yes No Yes No

Btrfs Partial[123] No Yes Yes Yes Yes

DECtape No No No No No No

Level-D Yes No Yes No No No

DOS (GEC) No Yes Yes No No No

OS4000 No Yes Yes No No No

V6FS No No No No Yes No

V7FS No No No No Yes No

FAT12 No No No No No No[124]

FAT16 No No No No No No[124]

Comparison of file systems 13

FAT32 No No No No No No

exFAT Unknown No No Unknown No No

GFS Partial[125] No No No Yes No

HPFS No No Yes No No No

NTFS Partial No Yes No Yes Partial[126]

HFS Plus No No Yes Yes No Yes

FFS 8:1[127] No No No Yes No

UFS1 8:1[127] No No No Yes No

UFS2 8:1[127] Yes No No Yes No

LFS 8:1[127] No No No Yes No

ext2 No[128] No No No Yes No[129]

ext3 No[128] No No No Yes No

ext3cow No[128] No No No Yes No

ext4 No[128] No Yes Yes Yes No

Lustre No No Yes Yes Yes No

NILFS No No No Yes Yes No

ReiserFS Yes No No No Yes No

Reiser4 Yes No Yes[130] Yes Yes Yes[106]

OCFS No No Yes No Unknown No

OCFS2 No No Yes No Yes No

Reliance No No No No No No

Reliance Nitro No No Yes No Yes No

XFS No No Yes Yes Yes No

JFS Yes No Yes No Yes only in JFS1 on AIX[131]

QFS Yes No No No Unknown No

BFS No No Yes No Unknown No

NSS No No Yes No Unknown Yes

NWFS Yes[132] No No No Unknown Yes

ODS-5 No No Yes No Unknown No

VxFS Unknown No Yes No Yes No

UDF No No Yes Depends[133] No No

Fossil No No No No Unknown Yes

VMFS2 Yes No No No Yes No

VMFS3 Yes No Yes No Yes No

ZFS Partial[134] Yes No Yes Yes Yes

PramFS No No No No Yes No

Comparison of file systems 14

File system Block suballocation Variable file block size[121] Extents Allocate-on-flush Sparse files Transparent compression

Supporting operating systems

File system DOS Windows

9x

Windows NT Linux Mac OS Mac OS X FreeBSD BeOS Solaris AIX z/OS OS/2 Windows

CE

Windows

Mobile

VxWorks HP-UX

FAT12

Yes Yes Yes Yes Yes Yes Yes Yes No

Partial on

diskettes

only,

through

dos*

commands

Unknown Yes Yes[135] Unknown Yes

[136] Unknown

FAT16Yes since

DOS 3.0,

FAT16B

since

DOS 3.31

Yes Yes Yes Yes Yes Yes Yes Yes

Partial on

diskettes

only,

through

dos*

commands

Unknown Yes Yes[135] Yes Yes

[136] Unknown

FAT32

Yes since

DOS

7.1[137]

Yes since

Windows

95 OSR2

Yes since

Windows 2000Yes Yes Yes Yes Yes Yes

Partial on

diskettes

only,

through

dos*

commands

Unknownwith

third-party

app[] Yes

[135] Yes Yes[136] Unknown

exFAT

No

Partial

read-only

with third

party

driver

Yes : Win7, Vista

SP1, can be added

to XP SP2

with third party

driverNo Yes 10.6.5+ No No Yes No No No Yes No Unknown Unknown

NTFSwith

third-party

driver

with

third-party

driver[]

Yes

Yes Kernel 2.2

or newer, or with

NTFS-3G or

ntfsprogs

with

NTFS-3G

or

MacFUSE

Partial: read-only

(read-write with

NTFS-3G)

with NTFS-3Gwith

NTFS-3G

with NTFS-3G on

OpensolarisUnknown Unknown

Partial

read-only

third-party

driver[]

with

3rd-party

driver[138]

No Unknown Unknown

HFS

Nowith

third-party

app[]

with third-party

app[] Yes Yes

Partial: read-only

since OSX

10.6[]

with third-party

app[][] Unknown Unknown Unknown No

with

third-party

app[]

No No No Unknown

HFS Plus

Nowith

third-party

app[]

with third-party

app[]

Partial - write

support occurs if

journal is empty,

but requires a

force mount.

Yes since

Mac OS

8.1

Yes Partial read-only

third-party app[] Unknown Unknown Unknown No

with

third-party

app

No No No Unknown

HPFSwith

third-party

driver

Partial

read-only

third-party

driver[]

included until

v3.51, third-party

driver until

4.0[139]

Yes No Unknown Yes Unknown Unknown Unknown Unknown Yes No Unknown Unknown Unknown

FFS No Unknown Unknown Yes[] No Yes Yes Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

UFS1No Unknown Unknown

Partial - read

onlyNo Yes Yes Unknown Unknown Unknown Unknown Unknown Unknown Unknown No Unknown

UFS2No Unknown Unknown

Partial - read

onlyNo No Yes Unknown Unknown Unknown Unknown Unknown Unknown Unknown No Unknown

Comparison of file systems 15

ext2

Unknown Unknown

with Ext2Fsd

(complete)[140]

or Ext2 IFS

(partial, no large

inodes)[141]

or

Ext2Read

(read-only, also on

LVM2)[142]

Yes No

with

fuse-ext2,[143]

ExtFS[144]

and

ext2fsx[145]

Yes Unknown Unknown Unknown Unknown third-party

app[146]

with

3rd-party

app[147]

with

3rd-party

app[147]

Unknown Unknown

ext3

Unknown Unknown

with Ext2Fsd

(complete)[140]

or Ext2 IFS

(partial, no large

inodes)[141]

or

Ext2Read

(read-only, also on

LVM2)[142]

Yes Nowith

fuse-ext2[143]

and ExtFS[144]

Yes Unknown Yes Unknown Unknown Unknownwith

3rd-party

app[147]

with

3rd-party

app[147]

Unknown Unknown

ext3cowUnknown Unknown Unknown

Yes Kernel

2.6.20Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

ext4

No No

with Ext2Fsd

(partial, extents

limited)[140]

or

Ext2Read

(read-only, also on

LVM2)[142]

Yes since kernel

2.6.28No

with fuse-ext2

(partial)[143]

and ExtFS (full

read/write)[144]

No Unknown Unknown Unknown Unknown Unknown No Unknown Unknown Unknown

Btrfs No No No Yes No No No No No No No No No No Unknown Unknown

ZFS

No No No

with 3rd Party

kernel

module[148]

or

FUSE[149]

Nowith free

3rd-party

software[150]

Yes No Yes No No No Unknown Unknown Unknown Unknown

LustreNo No Partial - under

development[151] Yes

[152] NoPartial - via

FUSE

Partial - via

FUSENo Partial - under

development[153] No No No No No Unknown Unknown

GFS No Unknown Unknown Yes No Unknown No Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

NILFSNo Unknown Unknown

Yes since kernel

2.6.30No Unknown No Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

ReiserFS

No UnknownPartial with

third-party appYes No No

Partial - read

onlyUnknown Unknown Unknown Unknown Unknown

with

3rd-party

app[147]

with

3rd-party

app[147]

Unknown Unknown

Reiser4No Unknown Unknown

with a kernel

patchNo No No Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

OCFS No Unknown Unknown Yes No Unknown No Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

OCFS2 No Unknown Unknown Yes No Unknown No Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

Reliance No No No No No No No No No No No No Yes No Yes Unknown

Reliance

NitroNo No No Yes No No No No No No No No Yes Yes Yes Unknown

XFS No Unknown Unknown Yes No Unknown Partial Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

JFS No Unknown Unknown Yes No No No Unknown Unknown Yes Unknown Yes No No Unknown

QFSNo Unknown Unknown via client

software[154] No Unknown No Unknown Yes Unknown Unknown Unknown No No Unknown Unknown

Comparison of file systems 16

BFSNo Unknown Unknown

Partial -

read-onlyNo Unknown No Yes Unknown Unknown Unknown Unknown No No Unknown Unknown

NSSUnknown Unknown Unknown with Novell

OES2[citation needed]No Unknown No Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

NWFSUnknown Unknown Unknown via ncpfs client

software[155] No Unknown Yes Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

UDF

Unknown

Partial

read-only

support of

UDF 1.02

since

Win98

and

WinME

Yes[156] Yes

Yes since

Mac OS 9Yes Yes Unknown Yes Unknown Unknown Unknown Yes Unknown Unknown Unknown

VxFS No Unknown Unknown Yes No Unknown No Unknown Yes Yes Unknown Unknown No No Unknown Yes

Fossil No No No No No No No No No No No No No No No Unknown

IBM HFS No No No No No No No No No No Yes No Unknown Unknown Unknown Unknown

IBM zFS No No No No No No No No No No Yes No Unknown Unknown Unknown Unknown

IBM

GPFS[157] No No Yes Yes No No No No No Yes No No Unknown Unknown Unknown Unknown

VMFS2 Unknown Unknown Unknown Unknown No Unknown No Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

VMFS3No Unknown Unknown Partial read-only

with vmfs[158] Unknown Unknown No Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

DECtapeNo Unknown Unknown with

AncientFS[159] No with

AncientFS[159]

with

AncientFS[159] Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

Level-D No Unknown Unknown Unknown No Unknown No Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

RT-11 No Unknown Unknown Unknown No Unknown No Unknown Unknown Unknown Unknown Unknown No No Yes Unknown

ODS-2

No Unknown Unknown

Partial read-only

with tool or

kernel

module[160]

No Unknown No Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

ODS-5

No Unknown UnknownPartial read-only

with kernel

module[160]

No Unknown No Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown

LFSNo Unknown Unknown with logfs

[161]

and othersNo Unknown No Unknown Unknown Unknown Unknown Unknown No No Unknown Unknown

LTFS No Unknown Unknown Yes No Yes No No No No No No No No Unknown Unknown

PramFS No No No Yes No No No No No No No No No No No No

File system DOS Windows

9x

Windows NT Linux Mac OS Mac OS X FreeBSD BeOS Solaris AIX z/OS OS/2 Windows

CE

Windows

Mobile

VxWorks HP-UX

Comparison of file systems 17

Notes[1] http:/ / en. wikipedia. org/ wiki/ Comparison_of_file_systems#endnote_54[2] IBM introduced JFS with the initial release of AIX Version 3.1 in 1990. This file system now called JFS1. The new JFS, ported from OS/2 to

AIX and Linux, was first shipped in OS/2 Warp Server for e-Business in 1999. It was released as JFS2 on AIX 5L.[4] Microsoft first introduced FAT32 in Windows 95 OSR2 (OEM Service Release 2) and then later in Windows 98. NT-based Windows did not

have any support for FAT32 up to Windows NT4; Windows 2000 was the first NT-based Windows OS that received the ability to work withit.

[5] Specifications for the Reliance file systems are available here (http:/ / www. datalight. com/ products/ filesystems/reliance-family-specifications).

[6] These are the restrictions imposed by the on-disk directory entry structures themselves. Particular Installable File System drivers may placerestrictions of their own on file and directory names; and particular and operating systems may also place restrictions of their own, across allfilesystems. MS-DOS, Microsoft Windows, and OS/2 disallow the characters UNIQ-nowiki-0-a3de2c3c417b2102-QINU in file and directorynames across all filesystems. Unix-like systems disallow the characters UNIQ-nowiki-1-a3de2c3c417b2102-QINU in file and directory namesacross all filesystems.

[7] For filesystems that have variable allocation unit (block/cluster) sizes, a range of size are given, indicating the maximum volume sizes for theminimum and the maximum possible allocation unit sizes of the filesystem (e.g. 512 bytes and 128 kB for FAT — which is the cluster sizerange allowed by the on-disk data structures, although some Installable File System drivers and operating systems do not support cluster sizeslarger than 32 kB).

[8][8] While the on-disk filesystem structure uses a 4-byte file length, which allows files up to 4G, the usual disk access APIs use the top three bitsof the sector number to specify the drive number, effectively limiting the maximum file size to 512M.

[9][9] While the on-disk filesystem structure uses a 3-byte sector number, which allows access to 4G of disk space, the usual disk access APIs usethe top three bits of the sector number to specify the drive number, effectively limiting the maximum disk size to 512M.

[10][10] The CP/M filesystem itself does have limitations in regard to the allowed filename characters to be used, but officially the followingcharacters are not allowed: UNIQ-nowiki-2-a3de2c3c417b2102-QINU . CCP reserves the following characters for special purposes:UNIQ-nowiki-3-a3de2c3c417b2102-QINU , PIP additionally reserves: UNIQ-nowiki-4-a3de2c3c417b2102-QINU .

[12] Depends on whether the FAT12, FAT16, and FAT32 implementation has support for long filenames (LFNs). Where it does not, as in OS/2,MS-DOS, Windows 95, Windows 98 in DOS-only mode and the Linux "msdos" driver, file names are limited to 8.3 format of 8-bit characters(space padded in both the basename and extension parts) and may not contain NUL (end-of-directory marker) or character 5 (replacement forcharacter 229 which itself is used as deleted-file marker). Short names also do not normally contain lowercase letters. Also note that a fewspecial names (CON, NUL, LPT1) should be avoided, as some operating systems (notably DOS and windows) effectively reserve them.

[13][13] In these filesystems the directory entries named "." and ".." have special status. Directory entries with these names are not prohibited, andindeed exist as normal directory entries in the on-disk data structures. However, they are mandatory directory entries, with mandatory values,that are automatically created in each directory when it is created; and directories without them are considered corrupt.

[14] The on-disk structures have no inherent limit. Particular Installable File System drivers and operating systems may impose limits of theirown, however. MS-DOS/PC DOS do not support full pathnames longer than 66 bytes for FAT12, FAT16 and FAT32 volumes. This limitexists because these operating systems were designed around a fixed-length internal data structure named Current Directory Structure, whichholds the absolute paths of the current working directories of all volumes. The FAT12/FAT16 file system implementation under ConcurrentDOS and DR DOS 3.31 to 6.0 (prior to 1992 updates) did not impose any such limits on the directory depth due to their internal representationof current working directories as dynamically updated chain of double-linked relative directories. The introduction of a DOS-like CDS(instead of only an emulation thereof) for compatibility purposes with BDOS 7.0 in 1992 imposed the same length limits on PalmDOS, DRDOS 6.0 (since 1992 update), Novell DOS, OpenDOS, etc. as known from MS-DOS/PC DOS. Windows NT does not support full pathnameslonger than 32,767 bytes for NTFS. Most Windows programs will fail when full path exceeds 255 characters (including Explorer andCMD.EXE). Linux has a pathname limit of 4,096.

[15] See manual http:/ / wwwlehre. dhbw-stuttgart. de/ ~helbig/ os/ v6/ doc/ V/ fs. html[16] The actual maximum was 1,082,201,088 bytes, with 10 direct blocks, 1 singly indirect block, 1 doubly indirect block, and 1 triply indirect

block. The 4.0BSD and 4.1BSD versions, and the System V version, used 1,024-byte blocks rather than 512-byte blocks, making themaximum 4,311,812,608 bytes or approximately 4 GB.

[17] Table "Limits" states a maximum of 255 Unicode characters for the filename (http:/ / msdn. microsoft. com/ en-us/ library/ ee681827(VS.85). aspx)

[18] Udo Kuhnt, Luchezar Georgiev, Jeremy Davis (2007). FAT+. FATPLUS.TXT, draft revision 2 ( (http:/ / www. unet. univie. ac. at/~a0503736/ php/ drdoswiki/ index. php?n=Main. FATplus), (http:/ / www. fdos. org/ kernel/ fatplus. txt)).

[19] While FAT32 partitions this large work fine once created, some software won't allow creation of FAT32 partitions larger than 32 GB. Thisincludes, notoriously, the Windows XP installation program and the Disk Management console in Windows 2000, XP, 2003 and Vista. UseFDISK from a Windows ME Emergency Boot Disk to avoid. (http:/ / support. microsoft. com/ kb/ 314463)

[20] As Mac OS X is a Unix-like system, which supports UNIQ-nowiki-5-a3de2c3c417b2102-QINU in file names, and which usesUNIQ-nowiki-6-a3de2c3c417b2102-QINU as a pathname component separator, SPACE $ & % @ \ ^ : . # * " ¦ in file names is represented ondisk in HFS and HFS+ as UNIQ-nowiki-8-a3de2c3c417b2102-QINU .

Comparison of file systems 18

[21] The "." and ".." directory entries in HPFS that are seen by applications programs are a partial fiction created by the Installable File Systemdrivers. The on-disk data structure for a directory does not contain entries by those names, but instead contains a special "start" entry. Whilston-disk directory entries by those names are not physically prohibited, they cannot be created in normal operation, and a directory containingsuch entries is corrupt.

[22] This is the limit of the on-disk structures. The HPFS Installable File System driver for OS/2 uses the top 5 bits of the volume sector numberfor its own use, limiting the volume size that it can handle to 64 GB.

[23] NTFS allows files to have multiple names, in separate namespaces: Win32, DOS, Win32&DOS, and Posix. Windows APIs create files withWin32 "long" names (1–255 characters), sometimes with an additional "short"/"alias" DOS name in the "8.3" format (12 characters).

[24] NB: This article includes discussion of the NT & Win32 namespaces used by Windows APIs; these are distinct from the NTFS filenamenamespaces.

[25] In the Win32 namespace, any UTF-16 code unit (case insensitive) except NUL and UNIQ-nowiki-9-a3de2c3c417b2102-QINU is allowed;in the Posix namespace, any UTF-16 code unit (case sensitive) except NUL and / is allowed; in the DOS namespace, any character in theU+0021–U+007E range except SPACE < > . , ; : = ? * [ ] % | ( ) / \ is allowed. Windows APIs require Win32 namespace compatibility, whichprevents access to folders & files having only Posix names containing Win32-incompatible characters.

[26] This is the limit of the on-disk structures. The NTFS driver for Windows NT limits the volume size that it can handle to 256 TB and the filesize to 16 TB respectively.

[28][28] The Mac OS provides two sets of functions to retrieve file names from an HFS Plus volume, one of them returning the full Unicode names,the other shortened names fitting in the older 31 byte limit to accommodate older applications.

[29] HFS Plus mandates support for an escape sequence to allow arbitrary Unicode. Users of older software might see the escape sequencesinstead of the desired characters.

[31] ext4 1.42 (http:/ / e2fsprogs. sourceforge. net/ e2fsprogs-release. html#1. 42) "This release of e2fsprogs has support for file systems > 16TB"

[32][32] Depends on kernel version and arch. For 2.4 kernels the max is 2 TB. For 32-bit 2.6 kernels it is 16 TB. For 64-bit 2.6 kernels it is 8 EB.[33] ReiserFS has a theoretical maximum file size of 1 EB, but "page cache limits this to 8TB on architectures with 32 bit int" (http:/ / www.

namesys. com/ faq. html#reiserfsspecs)[34][34] QFS allows files to exceed the size of disk when used with its integrated HSM, as only part of the file need reside on disk at any one time.[35][35] Varies wildly according to block size and fragmentation of block allocation groups.[36][36] NSS allows files to have multiple names, in separate namespaces.[37] Some namespaces had lower name length limits. "LONG" had an 80-byte limit, "NWFS" 80 bytes, "NFS" 40 bytes and "DOS" imposed 8.3

filename.[38][38] Maximum combined filename/filetype length is 236 bytes; each component has an individual maximum length of 255 bytes.[39][39] Maximum pathname length is 4,096 bytes, but quoted limits on individual components add up to 1,664 bytes.[40][40] This restriction might be lifted in newer versions.[41] 232 × block size[42][42] Maximum file size on a VMFS volume depends on the block size for that VMFS volume. The figures here are obtained by using the

maximum block size.[43][43] ISO 9660#Restrictions[44] Through the use of multi-extents, a file can consist of multiple segments, each up to 4 GB in size. See ISO 9660#The 2/4 GB file size limit[45][45] Assuming the typical 2048 Byte sector size. The volume size is specified as a 32-bit value identifying the number of sectors on the volume.[46] Joliet Specification (http:/ / bmrc. berkeley. edu/ people/ chaffee/ jolspec. html)[47] https:/ / raw. github. com/ danrl/ lanyfs-docs/ master/ lanyfs-1. 4. txt[49] Note that the filename can be much longer XFS#Extended_attributes[50] XFS has a limitation under Linux 2.4 of 64 TB file size, but Linux 2.4 only supports a maximum block size of 2 TB. This limitation is not

present under IRIX.[51][51] Implemented in later versions as an extension[52] Concurrent DOS, FlexOS, Multiuser DOS, REAL/32, PalmDOS, Novell DOS, OpenDOS, and DR-DOS can store file owner information in

reserved fields of directory entries on FAT12 and FAT16 volumes, if the optional multi-user security module is loaded. If loaded, mostexternal commands invoke support for special /U:owner/group command line options to deal with this extra information.

[53] Concurrent DOS, FlexOS, Multiuser DOS, REAL/32, DR DOS, PalmDOS, Novell DOS, OpenDOS, and DR-DOS can storeread/write/delete/execute access permissions and file/directory passwords in reserved fields of directory entries on FAT12 and FAT16volumes. This is an integral part of the design, therefore passwords can be appended to file or directory names with semicolon (for example:dirname;dirpwd\filename;filepwd), the PASSWORD command can be used to control permissions and some commands support a special/P:pwd option to deal with this feature.

[54][54] File creation and file access timestamps are supported only by DOS 7.0 and higher, and typically only when explicitly enabled.[55][55] Some FAT implementations, such as in Linux, show file modification timestamp (mtime) in the metadata change timestamp (ctime) field.

This timestamp is however, not updated on file metadata change.[56] Particular Installable File System drivers and operating systems may not support extended attributes on FAT12 and FAT16. The OS/2 and

Windows NT filesystem drivers for FAT12 and FAT16 support extended attributes (using a "EA DATA. SF" pseudo-file to reserve theclusters allocated to them). Other filesystem drivers for other operating systems do not.

Comparison of file systems 19

[57] The f-node contains a field for a user identifier. This is not used except by OS/2 Warp Server, however.[58] NTFS access control lists can express any access policy possible using simple POSIX file permissions (and far more), but use of a

POSIX-like interface is not supported without an add-on such as Services for UNIX or Cygwin.[59] As of Vista, NTFS has support for Mandatory Labels, which are used to enforce Mandatory Integrity Control. See (http:/ / msdn2. microsoft.

com/ en-us/ library/ bb648648. aspx)[61][61] Access-control lists and MAC labels are layered on top of extended attributes.[62][62] Some operating systems implemented extended attributes as a layer over UFS1 with a parallel backing file (e.g., FreeBSD 4.x).[63] Some Installable File System drivers and operating systems may not support extended attributes, access control lists or security labels on

these filesystems. Linux kernels prior to 2.6.x may either be missing support for these altogether or require a patch.[64] ext4 has group descriptor, journal and, starting from Linux kernel 3.5, metadata checksumming[65][65] Creation time is stored in the backing ext4 filesystem, but is not yet sent to clients.[66][66] Lustre has checksums for data over the network, but depends on backing filesystem and hardware for checksums of persistent data[67][67] Not available with ext3/4, but will be available with ZFS OST/MDT backing filesystems.[68][68] ocfs2 computes and validates checksums of metadata objects like inodes and directories. It also stores an error correction code capable to

fixing single-bite errors.[69][69] CRCs are employed for certain types of metadata.[70] The local time, timezone/UTC offset, and date are derived from the time settings of the reference/single timesync source in the NDS tree.[71][71] Novell calls this feature "multiple data streams". Published specifications say that NWFS allows for 16 attributes and 10 data streams, and

NSS allows for unlimited quantities of both.[72] Some file and directory metadata is stored on the NetWare server irrespective of whether Directory Services is installed or not, like

date/time of creation, file size, purge status, etc; and some file and directory metadata is stored in NDS/eDirectory, like file/objectpermissions, ownership, etc.

[73][73] Record Management Services (RMS) attributes include record type and size, among many others.[74] File permission in 9P are a variation of the traditional Unix permissions with some minor changes, e.g. the suid bit is replaced by a new

'exclusive access' bit.[75][75] MAC/Sensitivity labels are per filesystem. A label per file are not out of the question as a future compatible change but aren't part of any

available version of ZFS.[76][76] Solaris "extended attributes" are really full-blown alternate data streams, in both the Solaris UFS and ZFS. ZFS also has "system attributes"

used for storing MS-DOS/NTFS compatible attributes for use by CIFS; as well as some attributes ported from FreeBSD[77][77] Time the file was recorded on the volume always available; "File Creation Date and Time" available only if the file has an Extended

Attribute block.[78][78] Not applicable to file systems on a read-only medium.[79][79] Available only if the file has an Extended Attribute block.[80][80] Symlinks only visible to NFS clients. References and Off-Disk Pointers (ODPs) provide local equivalent.[81] System V Release 4, and some other Unix systems, retrofitted symbolic links to their versions of the Version 7 Unix file system, although

the original version didn't support them.[82][82] Context based symlinks were supported in GFS, GFS2 only supports standard symlinks since the bind mount feature of the Linux VFS has

made context based symlinks obsolete[83][83] Optional journaling of data[84] As of Windows Vista, NTFS fully supports soft links. See this Microsoft article on Vista kernel improvements (http:/ / www. microsoft.

com/ technet/ technetmag/ issues/ 2007/ 02/ VistaKernel/ default. aspx). NTFS 5.0 (Windows 2000) and higher can create junctions (http:/ /support. microsoft. com/ kb/ 205524), which allow any valid local directory (but not individual files) ("target" of junction) to be mapped to anNTFS version thereof ("source" = location of junction). The source directory must lie on an NTFS 5+ partition, but the target directory can lieon any valid local partition and needn't be NTFS. Junctions are implemented through reparse points, which allow the normal process offilename resolution to be extended in a flexible manner.

[85][85] NTFS stores everything, even the file data, as meta-data, so its log is closer to block journaling.[86] While NTFS itself supports case sensitivity, the Win32 environment subsystem cannot create files whose names differ only by case for

compatibility reasons. When a file is opened for writing, if there is any existing file whose name is a case-insensitive match for the new file,the existing file is truncated and opened for writing instead of a new file with a different name being created. Other subsystems like e. g.Services for Unix, that operate directly above the kernel and not on top of Win32 can have case-sensitivity.

[87] NTFS does not internally support snapshots, but in conjunction with the Volume Shadow Copy Service can maintain persistent blockdifferential volume snapshots.

[88][88] Mac OS System 7 introduced the 'alias', analogous to the POSIX symbolic link but with some notable differences. Not only could they crossfile systems but they could point to entirely different file servers, and recorded enough information to allow the remote file system to bemounted on demand. It had its own API that application software had to use to gain their benefits-- this is the opposite approach from POSIXwhich introduced specific APIs to avoid the symbolic link nature of the link. The Finder displayed their file names in an italic font (at least inRoman scripts), but otherwise they behaved identically to their referent.

[90][90] Metadata-only journaling was introduced in the Mac OS 10.2.2 HFS Plus driver; journaling is enabled by default on Mac OS 10.3 and later.

Comparison of file systems 20

[91] Although often believed to be case sensitive, HFS Plus normally is not. The typical default installation is case-preserving only. From MacOS 10.3 on the command newfs_hfs -s (http:/ / developer. apple. com/ documentation/ Darwin/ Reference/ ManPages/ man8/ newfs_hfs. 8.html) will create a case-sensitive new file system. HFS Plus version 5 optionally supports case-sensitivity. However, since case-sensitivity isfundamentally different from case-insensitivity, a new signature was required so existing HFS Plus utilities would not see case-sensitivity as afile system error that needed to be corrected. Since the new signature is 'HX', it is often believed this is a new filesystem instead of a simply anupgraded version of HFS Plus. See Apple's File System Comparisons (http:/ / developer. apple. com/ documentation/ MacOSX/ Conceptual/BPFileSystem/ Articles/ Comparisons. html) (which hasn't been updated to discuss HFSX) and Technical Note TN1150: HFS Plus VolumeFormat (http:/ / developer. apple. com/ technotes/ tn/ tn1150. html) (which provides a very technical overview of HFS Plus and HFSX).

[92] Mac OS Tiger (10.4) and late versions of Panther (10.3) provide file change logging (it's a feature of the file system software, not of thevolume format, actually). See fslogger (http:/ / www. kernelthread. com/ software/ fslogger/ ).

[93][93] As of OS X 10.7, HFS+ supports full volume file encryption known as Filevault 2.[94] Since Mac OS X Snow Leopard, online resizing is supported.[95] "Write Ahead Physical Block Logging" in NetBSD, provides metadata journaling and consistency as an alternative to softdep.[97] "Soft dependencies" (softdep) in NetBSD, called "soft updates" in FreeBSD provide meta-data consistency at all times without double writes

(journaling).[98][98] Block level journals can be added by using gjournal module in FreeBSD.[100] UDF, LFS, and NILFS are log-structured file systems and behave as if the entire file system were a journal.[101][101] Linux kernel versions 2.6.12 and newer.[102][102] Offline growing/shrinking as well as online growing:[103][103] Off by default.[104][104] Can be shrunk online by migrating files off an OST and removing the OST, or offline with ext3/4 backing filesystems by shrinking the

OST filesystem[105][105] Full block journaling for ReiserFS was not added to Linux 2.6.8 for obvious reasons.[106] Reiser4 supports transparent compression and encryption with the cryptcompress plugin which is the default file handler in version 4.1.[107][107] OCFS2 supports creating multiple write-able snapshots of regular files using REFLINK.[108][108] File system implements reliability via atomic transactions.[109][109] Optionally no on IRIX.[110] Particular Installable File System drivers and operating systems may not support case sensitivity for JFS. OS/2 does not, and Linux has a

mount option for disabling case sensitivity.[111] (http:/ / www. linux. com/ archive/ feed/ 32002)[112][112] Case-sensitivity/Preservation depends on client. Windows, DOS, and OS/2 clients don't see/keep case differences, whereas clients

accessing via NFS or AFP may.[113] The file change logs, last entry change timestamps, and other filesystem metadata, are all part of the extensive suite of auditing capabilities

built into NDS/eDirectory called NSure Audit. ( Filesystem Events tracked by NSure (http:/ / www. novell. com/ documentation/ nsureaudit/html/ netware_event_data. htm))

[114][114] Available only in the "NFS" namespace.[115] Limited capability. Volumes can span physical disks (volume segment)[116][116] These are referred to as "aliases".[117][117] VxFS provides an optional feature called "Storage Checkpoints" which allows for advanced file system snapshots.[118] When used with venti.[119][119] ZFS is a transactional filesystem using copy-on-write semantics, guaranteeing an always-consistent on-disk state without the use of a

traditional journal. However, it does also implement an intent log to provide better performance when synchronous writes are requested.[121] Variable block size refers to systems which support different block sizes on a per-file basis. (This is similar to extents but a slightly

different implementational choice.) The current implementation in UFS2 is read-only.[122][122] only for .REL (record structured) files, up to 254 bytes/record[123][123] Btrfs can only inline files smaller than 3916B with its metadata[124] SuperStor in DR DOS 6.0 and PC DOS 6.1, DoubleSpace in MS-DOS 6.0, DriveSpace in MS-DOS 6.22, Windows 95 and Windows 98,

and Stacker in Novell DOS 7, OpenDOS 7.01, DR-DOS 7.02/7.03 and PC DOS 7.0/2000 were data compression schemes for FAT.[125][125] Only for "stuffed" inodes[126][126] Only if formatted with 4kB-sized clusters or smaller[127][127] Other block:fragment size ratios supported; 8:1 is typical and recommended by most implementations.[128][128] Fragments were planned, but never actually implemented on ext2 and ext3.[129] e2compr, a set of patches providing block-based compression for ext2, has been available since 1997, but has never been merged into the

mainline Linux kernel.[130][130] In "extents" mode.[132][132] Each possible size (in sectors) of file tail has a corresponding suballocation block chain in which all the tails of that size are stored. The

overhead of managing suballocation block chains is usually less than the amount of block overhead saved by being able to increase the blocksize but the process is less efficient if there is not much free disk space.

[133][133] Depends on UDF implementation.

Comparison of file systems 21

[134][134] When enabled, ZFS's logical-block based compression behaves much like tail-packing for the last block of a file.[135] Files, Databases, and Persistent Storage (http:/ / msdn. microsoft. com/ en-us/ library/ ms899821. aspx). MSDN.[136][136] Via dosFs.[137][137] Native FAT32 support with MS-DOS 7.10 and 8.0. Loadable FAT32 support for any DOS since 3.31 with DRFAT32 redirector driver.

Native FAT32 support since OEM DR-DOS 7.04, bootable FAT32 support since OEM DR-DOS 7.06. Native FAT32 support with OEM PCDOS 7.10.

[138] Tuxera NTFS for Windows CE. See article (http:/ / www. windowsfordevices. com/ c/ a/ News/ Tuxera-NTFS-for-Windows-CE/ ) andannouncement (http:/ / www. tuxera. com/ about-us/ news/ 1915/ ).

[139] Win NT 4.0 HPFS Driver (http:/ / hobbes. nmsu. edu/ h-viewer. php?dir=/ pub/ windows& file=hpfsnt. zip)[140] Ext2Fsd is an open source ext2/ext3/ext4 kernel-level file system driver for Windows systems (NT/2K/XP/VISTA/7, X86/AMD64) that

provides both read/write access to the file system. Currently, does not fully support extents (no size truncating/extending, no file deletion), adefault feature of ext4. (http:/ / www. ext2fsd. com/ )

[141] Ext2 IFS for Windows provides kernel-level read/write access to ext2 and ext3 volumes in Windows NT4, 2000, XP, Vista and Windows2008. Does not support inodes size above 128 bytes and does not support ext4. (http:/ / www. fs-driver. org/ faq. html)

[142] Ext2Read is an explorer-like utility to explore ext2/ext3/ext4 file systems that provides read-only access to the file system. It supportsextents, large inodes, and LVM2 volumes. Ext2Read (http:/ / sourceforge. net/ projects/ ext2read/ )

[143] Fuse-ext2 is a multi OS FUSE module to mount ext2 and ext3 file system devices and/or images with read and write support. (http:/ /fuse-ext2. sourceforge. net/ )

[144] Paragon ExtFS for Mac is a low-level file system driver specially developed to bridge file system incompatibility between Linux and Macby providing full read/write access to the Ext2, Ext3 and Ext4 file systems under Mac OS X. (http:/ / www. paragon-software. com/ home/extfs-mac/ )

[145] Ext2fsx is the first and old implementation of the Ext2 (Linux) filesystem for Mac OS X. (http:/ / sourceforge. net/ projects/ ext2fsx/ )[146] OS/2 ext2 Driver (http:/ / hobbes. nmsu. edu/ h-viewer. php?dir=/ pub/ os2/ system/ drivers/ filesys& file=ext2_240. zip)[147] See Total Commander, which supports accessing ext2, ext3, and ReiserFS from Windows, Windows CE, and Windows Mobile.[148] Native ZFS for Linux (http:/ / zfsonlinux. org/ )[149] ZFS on FUSE (http:/ / www. wizy. org/ wiki/ ZFS_on_FUSE)[150] Mac ZFS (http:/ / code. google. com/ p/ maczfs/ )[151] http:/ / wiki. lustre. org/ index. php/ Windows_Native_Client[152] http:/ / wiki. lustre. org/ index. php?title=Main_Page[153] http:/ / wiki. lustre. org/ index. php/ FAQ_-_OS_Support[154] Using SAM-QFS on Linux Clients (http:/ / wikis. sun. com/ display/ SAMQFSDocs/ Using+ SAM-QFS+ on+ Linux+ Clients)[155] ncpfs (http:/ / freshmeat. net/ projects/ ncpfs/ )[157] (http:/ / www-03. ibm. com/ systems/ software/ gpfs/ )[158] vmfs (http:/ / code. google. com/ p/ vmfs/ )[159] AncientFS (http:/ / osxbook. com/ software/ ancientfs/ )[160] VMS2Linux (http:/ / www. vms2linux. de/ )[161] logfs (http:/ / logfs. sourceforge. net/ )

External links• Linux kernel file systems (http:/ / howto. wikia. com/ wiki/ Howto_configure_the_Linux_kernel/ fs) via

Wikia:en.howto:Wikihowto• A speed comparison of filesystems on Linux 2.4.5 (http:/ / web. archive. org/ web/ 20040407211142/ aurora.

zemris. fer. hr/ filesystems/ ) (archived)

Article Sources and Contributors 22

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