Cache Pool:0 causing high utilization and slow performance

  • 7004983
  • 07-Dec-2009
  • 26-Apr-2012

Environment

Novell NetWare 6.5 Support Pack 8
Novell NetWare 6.5 Support Pack 7
Novell NetWare 6.5 Support Pack 6

Situation

Every couple of weeks, the server would slow down its performance, causing slow logins and file access. Monitor.nlm -- kernel -- busiest threads would show the cache pool:0 process taking up large amounts of CPU time. The slowness seemed to correspond with this thread. Utilization would hover at about 25-30%.

Resolution

The server had 2 gig of memory. The file cache maximum size parameter was set at 2 gig. The meant that the deallocated memory given to the VM cache pool from applications, would always be mapped back to the file cache pool. This is why the cache pool:0 thread was constantly running, taking up all the CPU time. The solution was to set the file cache maximum size to 1 gig. This would give each pool, the VM and the FScache, a gig of memory to work with. Another solution would have been to add another gig of ram to the server. This would negate the need to constantly map memory back down the the FS cache pool as the size of this pool was now smaller than the amount of memory in the server. The problem only seemed to occur with 2 gig of memory with the file cache maximum size also set to 2 gig. With one gig of physical ram, the problem did not happen.

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