TSM MysteriesTSM Mysteriestsm-symposium.oucs.ox.ac.uk/2007/papers/Bruno Friess_Michael Abel... · using AIO interface offered by AIX. C ll t ll IO i t bi IO U ... IOs to the disk

TSM MysteriesTSM MysteriesTSM Mysteries TSM Mysteries ––Server MemoryServer MemoryServer MemoryServer Memory

Episode 1 Oxford UniversityyTSM Symposium 2007

Michael Abel & Bruno FriessMichael Abel & Bruno Friess

AgendaWhy care for memory?

fTypes of memoryTSM memory mapTSM memory mapTSM memory tuningMemory layoutMemory analysisMemory analysis

(c) 2006-2007 by eXstor GmbH 201.08.2007

WarningsFor commands, settings, options, values limites implicationsvalues, limites, implications…Check documentation valid for OS, ,TSM server and TSM client level used in your specific environmentin your specific environment

(c) 2006-2007 by eXstor GmbH 301.08.2007

Why care for memory?TSM Server needs memory

f MB… from some MBs… up to several GBs

What we want to know:What is memory used for?What is memory used for?Does size really matter?How to tune memory inside TSMHow to tune memory on the OSyHow to get more out of less

(c) 2006-2007 by eXstor GmbH 401.08.2007

What if we ignore……all those fancy foils?

Worst case scenario:Worst case scenario:TSM server hogs up all memoryOS i i t fOS is running out of memoryOS has to page/swap processesPaging creates unwanted IOsPerformance of system goes downPerformance of system goes downPerformance of TSM goes downTSM admin is in deep t o ble

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TSM admin is in deep trouble

Types of memoryMost operating systems separate memory into different typesmemory into different types

Executable binary codeExecutable (shared) librariesPrivate dataPrivate dataShared dataK lKernel memory…

Differentiation necessary forProtection paging caching sharing

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Protection, paging, caching, sharing…

TSM memory map

TSM BUFPOOL

TSM LOGPOOL

Other Data

TSM Code (dsmserv)

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Svmon of dsmserv

dsmserv code

Data (Bufpool)

adsmserv.lock

diskpool

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diskpooldatabase vollog vol

TSM memory tuningBUFPOOLSIZE

S t i d tSet in dsmserv.optGiven in KBMinimum = 256Default = 32768Default 32768Maximum = virtual memory

Visible as real memory consumptiony pConservative value 1/8-1/2 of RAM

(c) 2006-2007 by eXstor GmbH 901.08.2007

TSM memory tuningLOGPOOLSIZE

Set in dsmserv optSet in dsmserv.optSpecified in KBMi i 128Minimum = 128Default = 512Maximum = virtual memory

Visible as real memory consumptionOld max value known 8192Old max value known 8192Performance effect hard to prove

(c) 2006-2007 by eXstor GmbH 1001.08.2007

TSM memory tuningAIXASYNCIO

S f DB I/O h bServer performs DB I/O asynchronous by using AIO interface offered by AIX. C ll t ll IO i t bi IO U dCollects smaller IOs into one big IO. Used for databases like Oracle.

AIXDIRECTIOBypass AIX file cache when performingBypass AIX file cache when performing IOs to the disk storage pools. Can be specified on the filesystem level alsospecified on the filesystem level also (mount option)

(c) 2006-2007 by eXstor GmbH 1101.08.2007

Tuning strategy V1Use all available memory

OO lIncrease BUFPOOL as long as system does not start to pagep g

Si l t dSimple to doMay not fit your environmenty yOnly feasible for systems with small amount of RAMamount of RAM

(c) 2006-2007 by eXstor GmbH 1201.08.2007

Tuning strategy V2Use necessary memory

OO f fSet BUFPOOLSIZE to ½ of free memoryyMonitor „cache hit percentage“ with query database format=detail“„query database format=detail

Increase memory if value < 98%

Best way to do it but time consumingBest way to do it but time-consuming

(c) 2006-2007 by eXstor GmbH 1301.08.2007

Memory layout

TSM (code and data)TSM (code and data)

File System Cache (minimized!)

Operating System (code and buffers)

File System Cache (minimized!)

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Memory analysisUse OS specific tools

O f k l dUse OS specific knowledgePitfalls during analysisPitfalls during analysis

Shared elementsD i b ffDevice buffersFile cache

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SamplesSamples taken on real customer TSM serversserversSamples taken on AIX with „nmon“pCharts prepared with nmon analyzerL t ti d ilLong term reporting on daily or weekly basisPeriodic checks recommendedYour mileage may varyYour mileage may vary

(c) 2006-2007 by eXstor GmbH 1601.08.2007

Increase BUFPOOL

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No paging

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File IO

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Process memory

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Daily incremental

Memory Use tsmlpar1p1 08 07 2007Memory Use tsmlpar1p1 08.07.2007

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(c) 2006-2007 by eXstor GmbH 2101.08.2007

Optimized memory

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(c) 2006-2007 by eXstor GmbH 2201.08.2007

SummaryWhat we know by now:

Wh t i d f ?What is memory used for?Does size really matter?How to tune memory inside TSMHow to tune memory on the OSHow to tune memory on the OSHow to get more out of less

(c) 2006-2007 by eXstor GmbH 2301.08.2007

Q & A

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Please contactadress:

X t G bHeXstor GmbHHans-Bredow-Strasse 40D-65189 WiesbadenGermanyGermany

E-Mail: [email protected]: www.exstor.dePhone: +49 611 724286-0Phone: +49 611 724286 0

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