Re: Cleaners & Striped disks

In article <5i2j2k$k8j@cssun.mathcs.emory.edu>, Scott Hanson <shanson@lhr-co.gb.DHL.COM> writes >Hello all... > >I have an interesting one here. >We have an HP-UX 9000 10.01 with Informix 7.12. >The machine has 5x4.1GB disks allocated to Informix. >Two of these disks are partitioned into 2x2GB. No problem. >These contain rootdbs, llogspace and low use dbspaces > >The other three disks are striped using lvcreate to make 6x2GB partitions. >The stripe size is 32K. These contain plogdbs and one dbspace spread accross >the chunks. > >My question is...what is the optimum CLEANERS in this configuration? > >For the first two disks, 2 CLEANERS is appropriate right? >For the last three I would assume 3 CLEANERS but I am not sure what impact this >will have on checkpoint duration if the disks are striped. > >Scott >-- >Scott Hanson >Independant Database Consultant >Currently placed: shanson@gb.dhl.com It is always hard to tune striped disks as you cannot work out what the load will be on a given disk and you cannot make sure that all cleanign does not happen first on disk 1 then all on disk 2 etc. However in Online 7 CLEANERS only queue the page cleaning, KAIO threads/AIOVPS do the actual writing to disk. Therefore set CLEANERS=LRUS=NUMCPVPS. -- David Williams