On Thursday 12 June 2008, David Kelly wrote: > Apparently it won't read anything larger than your stripe size which > defaults to a miserable 4k.
Ugh. It seems like there are a few possibilities here, and I'm not sure which is actually true. Say you have two drives, striped. 1) Ideally, you could have a 512 byte stripe size. A program tries to read 4KB. Then, gstripe would issue a single request to each drive to read 4 blocks and interleaves the results. 2) Less ideally, you'd have a 128KB stripe size. A program requests a single block, but gstripe reads the entire stripe to fulfill the request. Not so hot for random access. 3) Worst, maybe? You have a 512 byte stripe. A program reads 4KB. gstripe reads 512B from da0, then 512B from da1, then 512B from da0, etc. Actually, I guess you could also have a combination of #2 and #3, where small reads fetch an entire stripe while large reads are broken into lots of tiny ones. So, back to gstripe. Which of those is it most like? > If there is a tuning knob that I have missed, would appreciate being > told what. Pass it along, would ya? :-) Oh, and don't forget to make your partition offsets -- Kirk Strauser
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