On Sunday 22 April 2007 10:47:59 Justin Piszcz wrote: > On Sun, 22 Apr 2007, Pallai Roland wrote: > > On Sunday 22 April 2007 02:18:09 Justin Piszcz wrote: > >> > >> How did you run your read test? > >> > > > > I did run 100 parallel reader process (dd) top of XFS file system, try > > this: for i in `seq 1 100`; do dd of=$i if=/dev/zero bs=64k 2>/dev/null; > > done for i in `seq 1 100`; do dd if=$i of=/dev/zero bs=64k 2>/dev/null & > > done > > > > and don't forget to set max_sectors_kb below chunk size (eg. 64/128Kb) > > /sys/block# for i in sd*; do echo 64 >$i/queue/max_sectors_kb; done > > > > I also set 2048/4096 readahead sectors with blockdev --setra > > > > You need 50-100 reader processes for this issue, I think so. My kernel > > version is 2.6.20.3 > > > > In one xterm: > for i in `seq 1 100`; do dd of=$i if=/dev/zero bs=64k 2>/dev/null; done > > In another: > for i in `seq 1 100`; do dd if=/dev/md3 of=$i.out bs=64k & done Write and read files top of XFS, not on the block device. $i isn't a typo, you should write into 100 files and read back by 100 threads in parallel when done. I've 1Gb of RAM, maybe you should use mem= kernel parameter on boot. 1. for i in `seq 1 100`; do dd of=$i if=/dev/zero bs=1M count=100 2>/dev/null; done 2. for i in `seq 1 100`; do dd if=$i of=/dev/zero bs=64k 2>/dev/null & done -- d - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
