Re: Cached reads too low

Tony Flaherty wrote: > > Hi, > Since reorganising my system I'm getting cached read percentage too low > warnings in oncockpit, [SNIP] > I have twelve smallish database across five disks. I've created each > database in its own dbspace and each dbspace has one chunk, I moved them by > dbexporting and then dbimporting into the new dbspaces, editing the schema > to change the extent info as necessary. One database has some tables in a > seperate dbspace on a seperate disk for performance reasons. I've increased > NUMAIOVPS from 4 to 10, as the manual suggests two per disk. > > The only other significant changes made during the reorg are; > * Added mirroring for rootdbs, llog dbs and physlog dbs > * added multiple temp dbspaces on different disks. I agree with Neil the engine is not up long enough to determine if the cache is working efficiently. Just look at the RA stats. You cannot have <1000 RA pages for normal operations with 147000 pagereads! You note that you added mirrors. Two things: 1) 7.24 only needs 1 to 1.5 aio VPs per disk not the 2 documented (7.30 gets by with 1 per disk) 2) did you count the number of mirror chunks in calculating the number of aio VPs you will need? You should. Art S. Kagel