Chapter 6 HPSS Configuration366 September 2002 HPSS Installation GuideRelease 4.5, Revision 2Thread Interval An interval, in seconds,that specifies how oftenthe cleanup threads wakeup to look for dirty entries.Any positive 32-bit integer value. 30 secondsAdvice: This value should not be too small because extra cleanup threads arespawned as needed when the cache starts to fill up.Dirty Threshold The percentage of diskcache entries that must bedirty before extra cleanupthreads are spawned.Any integer value between 1 and100.80 percentTouch Interval The interval, in seconds,that a disk cache entrymust not have beenaccessed in order for it tobe considered a candidateto be written back to HPSSby a cleanup thread.Any positive 32-bit integer value. 30 secondsAdvice: This value is ignored when the Dirty Threshold is exceeded. It isrecommended that this value be greater than the number of seconds the NFS clientcache holds on to dirty data.Touch Weight The importance of writingback to HPSS a dirty entrythat has not been accessedtoo recently.Any positive 32-bit integer value. 3Advice: The Touch Weight should be higher than the Dirty Weight to avoid lockingout access to cached data that has not been flushed to HPSS. A three to one ratio isrecommended (3 for Touch Weight, 1 for Dirty Weight).Dirty Weight The importance of writingback to HPSS a dirty entrythat has not been dirty fora long period of time.Any positive 32-bit integer value. 1Advice: The Dirty Weight should be lower than the Touch Weight to avoid lockingout access to cached data that has not been flushed to HPSS. A three to one ratio isrecommended (3 for Touch Weight, 1 for Dirty Weight).Table 6-28 NFS Daemon Configuration Variables (Continued)Display Field Name Description Acceptable Values DefaultValue
