16 NetIQ eDirectory 8.8 SP8 Tuning Guide
FLAIMsupportsablocksizeof4KBand8KB.Bydefault,itis4KB.Thisissameasthedefaultblock
sizeonLinux(
tune2fs -l device
).However,onSolaris,theUFSfilesystemiscreatedwitha
defaultblocksizeof8KB(
df -g mountpoint
).IftheFLAIMblocksizeissmallerthanthefilesystem
blocksize,partialblockwritescanhappen.Ifthedatabaseblocksizeislargerthanthefilesystem
blocksize,individualblockreadsandwritesaresplitintoaseriesofdistinctphysicalI/Ooperations.
Therefore,youshouldalwayskeepthe
FLAIMblocksizethesameasthefilesystemblocksize.
BlocksizescanbecontrolledonlyduringthecreationoftheDIB.Addaline“blocksize=8192”to
_ndsdb.ini
tocreatetheDIBwith8Kblocksize.
ChoosingtherightblocksizedependsontheaveragesizeoftheFLAIMrecordonyourdeployments.
Empiricaltestingisrequiredontherightsetoftestdatatodeterminewhichblocksizeisbetterfor
yourdeployment.
3.2 CPU Subsystem
eDirectoryisbuiltonahighlyscalablearchitecture.Theperformanceincreaseswiththeincreasein
thenumberofprocessors.Increasedthroughputisobserveduntilatleastthe12thprocessorunder
heavyload.However,thisincrease issubjecttotheperformanceofotherresourcesduringthe
increasingloadonthesystem.Servers
areoftenunder‐configuredwithdisksandmemory.You
shouldaddmoreprocessorsonlyunderthefollowingcircumstances:
Iftheaverageloadoncurrentlyusedprocessorsisbeyond75%percentutilization.Ifthecurrent
CPUutilizationisbelow75%,addingmoreCPUsmightnotimproveperformance.
Ifthereisa
satisfyingincreaseinperformance.
IfeDirectoryisconfiguredwithtoomanythreads,considerableamountofCPUtimeisspentin
contextswitching.Inthiscase, adecreaseinthreadscanresultinbetterthroughput.
3.3 Memory Subsystem
ServerapplicationscanperformsignificantlybetterwhenRAMisincreased.CachingtheeDirectory
databaseinthefilesystemorintheFLAIMcachecanleadtoimprovedperformancesofsearchand
modifyoperations.However,youcannotcachethecompleteDIBinlargedeployments.Avoidpage
swappingevenifitmeansreducingthe
FLAIMentryandblockcachesizes.Usethevmstattoolto
findmoreinformationonthememorysubsystem.
AseDirectoryusesmemory,eachthreadfromthethreadpooluses1MBofRAMforitsstack.By
default,theFLAIMcachesizeissetto200MB.
Severalloadablemodulesare
startedwheneDirectorystarts,buttheloadablemodulearchitectureof
eDirectoryallowsyoutoreducethememoryfootprintoftheprocessbynotloadingtheunused
modules(forexample,SecretStore,LDAP,oreMBox).Inaddition,productslikeIDMhavesome
modulesthatruninsideeDirectory.
ThememoryusedbyeDirectorymight
appeartobegrowing.Althoughmemoryisfreedbyan
eDirectoryprocess,itmightnotbereleasedtothesystemfreepoolbecausethememorymanager
usedinternallybyeDirectorytriestooptimizethememoryallocationsforfuture.Thisisoneofthe
reasonsfornotrecommendingFLAIMdynamicconfiguration.
UsetheToptooltofindthe
approximatevirtualmemorysizeofthendsdprocessinyourdeployment.
Themaximummemorythatcanbe allocatedtoaprocessislimitedinseveralways.Acertainamount
ofRAMisusedbytheoperatingsystemandotherprocessesonthesystem.The
operatingsystemcan
imposelimitationsonphysicalRAMthataprocessuses.