Chunk size for RAID

ssd7 · 03-11-2010, 11:53 AM

Hello,

what are your thoughts about the chunk size in RAID. how much chunk size should be used?

I read this but i did not get it completely.

Thank you.

troop · 03-11-2010, 11:58 AM

I tested various chank sizes. In my case turned out default is best. (3 hdd, raid10)

ssd7 · 03-11-2010, 12:02 PM

yes the default size 64kB is somewhat average

RaelOM · 03-11-2010, 02:44 PM

So first determine your system steady state.

http://www.linuxquestions.org/questi...-linux-748748/

Once you've done that determine the avgrq-sz using iostat -x <device> or sar -d.

Then calculate chunk size based on number of data disks in stripe.

Chunk size = avgrq-sz / # data disks