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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
(c) 2006-2007 by eXstor GmbH 501.08.2007
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
(c) 2006-2007 by eXstor GmbH 601.08.2007
Protection, paging, caching, sharing…
TSM memory map
TSM BUFPOOL
TSM LOGPOOL
Other Data
TSM Code (dsmserv)
(c) 2006-2007 by eXstor GmbH 701.08.2007
Svmon of dsmserv
dsmserv code
Data (Bufpool)
adsmserv.lock
diskpool
(c) 2006-2007 by eXstor GmbH 801.08.2007
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!)
(c) 2006-2007 by eXstor GmbH 1401.08.2007
Memory analysisUse OS specific tools
O f k l dUse OS specific knowledgePitfalls during analysisPitfalls during analysis
Shared elementsD i b ffDevice buffersFile cache
(c) 2006-2007 by eXstor GmbH 1501.08.2007
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
Daily incremental
Memory Use tsmlpar1p1 08 07 2007Memory Use tsmlpar1p1 08.07.2007
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Process% FScache% System%
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(c) 2006-2007 by eXstor GmbH 2101.08.2007
Optimized memory
Memory Use nsm4fix 16 07 2007Memory Use nsm4fix 16.07.2007
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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
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