Re: Question about optimum cache size.

[Chuck Lever]

lisa says:
< The current config we are running with is:
 
< GRANDE="-stat 2800 -dcache 4608 -daemons 7 -volumes 256"
 
< From my notes I have down that dcache indicates the number of cache item
< entries you want cached in memory. We set this to 75% of the # of vfiles 
< in the cache.

   that's very interesting.  i found that increasing the size of the
   dcache hash table larger than 500 caused degenerative hash behavior,
   resulting in degraded performance (because the kernel spent more
   and more time adding and searching entries in a few hash buckets
   instead of spreading the entries over the entire table).  this is
   also apparently true of the stat hash table.

   on our interactive systems, we keep the system on local disk and
   application software mostly in AFS, btw.

--
        Chuck Lever - [EMAIL PROTECTED]
          U-M ITD Login service team