Module 3 - Introduction to Cluster Shared Volumes and CSV ... · Module 3 - Introduction to Cluster Shared Volumes and CSV Architecture. Module Manual ... (covered in Lesson 3, later

Published: 4th September, 2012

Windows Server 2012: Storage

Module 3 - Introduction to Cluster Shared Volumes and

CSV Architecture.

Module Manual Author: David Coombes, Content Master

Microsoft Virtual Academy Student Manual ii

Information in this document, including URLs and other Internet Web site references, are subject to change without notice. Unless otherwise noted, the example companies, organizations, products, domain names, e-mail addresses, logos, people, places, and events depicted herein are fictitious, and no association with any real company, organization, product, domain name, e-mail address, logo, person, place or event is intended or should be inferred. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation. Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property. ® 2012 Microsoft Corporation. All rights reserved. Microsoft is either a registered trademark or trademark of Microsoft Corporation in the United States and/or other countries. The names of actual companies and products mentioned herein may be the trademarks of their respective owners.

Microsoft Virtual Academy Student Manual iii

Contents

CONTENTS .................................................................................................................................................................................................................. III

MODULE 3 - INTRODUCTION TO CLUSTER SHARED VOLUMES AND CSV ARCHITECTURE. .................................................... 4

Module Overview ................................................................................................................................................................................................ 4

LESSON 1: INTRODUCTION TO CLUSTER SHARED VOLUMES ............................................................................................................... 5

WHAT IS CSV? ............................................................................................................................................................................................................ 6

CSV IN WINDOWS SERVER 2008 R2 ................................................................................................................................................................. 7

CSV IN WINDOWS SERVER 2012 ....................................................................................................................................................................... 8

LESSON 2: CSV ARCHITECTURE .......................................................................................................................................................................... 9

CSV ARCHITECTURE IN WINDOWS SERVER 2012 ..................................................................................................................................... 10

CSV – I/O SYNCHRONIZATION OVERVIEW: 1 ............................................................................................................................................. 11

CSV – I/O SYNCHRONIZATION OVERVIEW: 2 ............................................................................................................................................. 12

METADATA UPDATES ........................................................................................................................................................................................... 13

CSVFS ARCHITECTURE – PROXY FILE SYSTEM ............................................................................................................................................ 14

CSV SINGLE NAMESPACE .................................................................................................................................................................................... 15

CSV NAMESPACE - MOUNT POINTS .............................................................................................................................................................. 16

CSV PROXY FILE SYSTEM ..................................................................................................................................................................................... 17

CSV SETUP ................................................................................................................................................................................................................. 18

Module 3 - Introduction to Cluster Shared Volumes and CSV Architecture.

Microsoft Virtual Academy Student Manual 4

Module 3 - Introduction to Cluster Shared Volumes

and CSV Architecture.

Module Overview

This module introduces the new technologies in Cluster Shared Volumes (CSV) v2 in Windows

Server® 2012 and describes how these features enable more resilient cluster storage and improved

performance and backup. It also explains deployment considerations for CSV v2 and describes how

CSV v2 works with other new failover clustering features.



Lesson 1: Introduction to Cluster Shared Volumes

This lesson explains CSV and the new CSV v2 features in Windows Server 2012.



What Is CSV?

CSV provides read/write access to applications running on all nodes in a cluster.

A single CSV can handle hundreds of virtual machines (VMs) and applications—there is no need for a

separate logical unit number (LUN) for each VM or application.

Fewer LUNs leads to less storage area network (SAN) complexity and fewer SAN zoning issues.

Each instance of CSV has its own namespace—CSV does not need to use drive letters, making it a

more scalable technology than mapped drives, for example.



CSV in Windows Server 2008 R2

CSV v1 only supported the Hyper-V workload and was used to enable Live Migration in Windows

Server 2008 R2.



CSV in Windows Server 2012

CSV v2 supports File Server and Hyper-V workloads.

Compared with CSV v1, more backup applications are now compatible with CSV and there is better

performance (block-level I/O improves performance by a factor of 2x). Direct I/O is now enabled in

more scenarios, for further performance gains.

Storage Spaces can be exposed as a LUN to the cluster and be added to CSV.

Server Message Block (SMB) 3.0 and new file system features are integrated into CSV v2.



Lesson 2: CSV Architecture

This lesson explains the architecture of CSV v2 in Windows Server 2012.


Microsoft Virtual Academy Student Manual

10

CSV Architecture in Windows Server 2012

With the new CSV architecture in Windows Server 2012, antivirus software is now compatible with

CSV, and more backup software is compatible with CSV. CSV v2 provides an infrastructure for

application-consistent distributed backups, making backup operations less complex.

CSV v2 also integrates with new Windows Server 2012 file system features, including Offloaded Data

Transfer (ODX) and spot-fixing.

Spot-fixing is part of the updated CHKDSK and enables zero downtime for CSV because scanning is

done online; only the spot-fixing itself (correcting errors) requires the volume to be taken offline.

Checks are made continually in real time, so when a fix is requested, CHKDSK already has a map of

all of the errors. Using virtual file handles (covered in Lesson 3, later in this module), the volume is

taken offline, is fixed, and then gets new virtual handles, and applications do not experience any

downtime.

Memory mapped I/O works on top of CSV.

CSV v2 does not need the Active Directory® directory service for authentication between cluster

nodes.



11

CSV – I/O Synchronization Overview: 1

CSV enables simultaneous read/write access to the shared LUN from all cluster nodes. Applications

can run on any node and can still write to a volume that is only mounted on one of the cluster nodes.



12

CSV – I/O Synchronization Overview: 2

Metadata synchronization is only done on one node (the coordinator node), and metadata changes

for all nodes are routed through that coordinator node.



13

Metadata Updates

Metadata updates are lightweight/small operations and only occur in specific situations, including:

Creating/deleting VMs.

Turning VMs on/off.

Moving VMs (Live Migration or Storage Live Migration).

Creating snapshots.

Extending a dynamic virtual hard disk (VHD).

Renaming a VHD.

Metadata changes occur in parallel—resulting in faster, non-disruptive operations for applications.



14

CSVFS Architecture – Proxy File System

The CSV file system (CSVFS) is accessible on all nodes in the cluster, and the CSV proxy file system

is mounted on all nodes.

Workload I/O, file server (share) or VM, first hits the file system.

If the I/O is not metadata I/O—that is, it is regular read/write I/O—the file system sends the I/O

directly down the stack to the storage and provides direct I/O performance.

For metadata changes only, the I/O is routed over the SMB path to the coordinator node. The

coordinator node is the only node where NTFS is mounted. For metadata, the NTFS layer handles the

changes.

The CSV proxy file system is present on all nodes, so applications can perform I/O simultaneously on

all cluster nodes.



15

CSV Single Namespace

Applications access the disk volume that the instance of CSV uses through a single namespace; in

the example in the screenshot, this namespace is C:\ClusterStorage\Volume1 and so on.

Each VolumeN represents a single instance of CSV, and you can rename VolumeN. For example,

based on the type of data that you are storing in the volume, you can rename the CSV as SQL-CSV1,

SQL-CSV2, VM-CSV1, etc.



16

CSV Namespace - Mount Points

Windows Server 2008 R2 used custom reparse points as CSV mount points. This meant that

applications, such as backup software, had to be written to be able to navigate through these

reparse points.

Windows Server 2012 uses standard mount points to make this process a lot easier for applications.



17

CSV Proxy File System

Using CSVFS, applications are aware that a volume is managed by CSV and that it is still NTFS

underneath.



18

CSV Setup

With Windows Server 2012, CSV is enabled by default. Next Step watch the Setting Up Cluster Shared Volumes demonstration video.

Module 3 - Introduction to Cluster Shared Volumes and CSV ... · Module 3 - Introduction to Cluster Shared Volumes and CSV Architecture. Module Manual ... (covered in Lesson 3, later

Documents