Re: Stripesize on Informix Raw devices

The best stripe size for Informix is 16K. Informix either does BUFFER writes of 2K or BIGWRITES of 16K so the 16K normally works out best. Remember that Informix is not normally write intensive, due to it's excellent buffer cache, so unless you are really stressing the system it may be very difficult to detect any improvement from striped -vs- singleton drives. You will see the biggest improvement from watching your checkpoint durations during load. Data load tests will rarely be affected by disk layout unless the loadset it MUCH larger than the buffer cache and is being inserted by MANY independent processes or threads. Art S. Kagel Marc Hopkins wrote: > > Does anyone have any experience with striping data on Informix raw devices. > We are running HPUX 10.20 on K420's. Informix reads and writes in 2K pages. > I have tried the stripesize of 4, which is the minimum HP allows, and > performance has not been any better than non-striped data. I have the data > striped across four disks. Anyone else using a diff stripesize? I am not > sure if I need to take into account the Informix Read-Ahead configuration. > Any suggestions welcome. Please send responses to email. > > Thanks, > Marc > marc.hopkins@aei.com