On Tue, Aug 29, 2006 at 10:27:26PM +0900, Tejun Heo wrote: > >>>2) hdparm -C for all 4 drives always shows "drive state is: standby" > >>> even when I'm certain that the drives are active. > >>hdparm -C says the same thing for my drive. I think it's safe to > >>ignore. Hmmm... it needs to be tracked down. Maybe some problem in > >>HDIO ioctl implementation in libata. > > > >It's a "nice to have" for using smartd. ie: don't spin the drives up to > >poll the failure attributes, but they should be checked if the drive's > >already active. > > I don't really understand what you mean. Can you elaborate? Sure. See the "-n standby" option here: http://smartmontools.sourceforge.net/man/smartd.conf.5.html If the driver always reports "standby", then smartd effectively won't monitor the device if "-n standby" is configured. Now I can certainly eliminate the -n option from smartd.conf, but then smartd will cause the drive(s) to spin up when it polls (see the -p, -u, -t options). > >>>I'd really like some assistance debugging the write performance issue. > >>>The "hdparm -C" issue would be gravy... > >>Please track down the reader. > > > >Before running dd (fuser -v /dev/sda1 shows nothing): > [--snip--] > > Can you try 'dd if=/dev/zero of=/dev/sdX bs=4M count=1'? Increasing the block size eliminates the reads (presumably because the block driver doesn't have to fetch lines to read/modify/write), but the write throughput is still very slow: # dd if=/dev/zero of=/dev/sda1 bs=4M count=512 avg-cpu: %user %nice %sys %iowait %idle 0.90 0.00 1.30 97.80 0.00 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn fd0 0.00 0.00 0.00 0 0 hda 0.20 0.80 0.00 8 0 md0 0.00 0.00 0.00 0 0 md1 0.00 0.00 0.00 0 0 sda 15.00 0.00 1920.00 0 19200 sdb 0.00 0.00 0.00 0 0 sdc 0.00 0.00 0.00 0 0 sdd 0.00 0.00 0.00 0 0 Compare that with: # dd of=/dev/null if=/dev/sda1 bs=4M count=512 avg-cpu: %user %nice %sys %iowait %idle 0.50 0.00 78.10 21.40 0.00 Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn fd0 0.00 0.00 0.00 0 0 hda 1.10 4.40 0.00 44 0 md0 0.00 0.00 0.00 0 0 md1 0.00 0.00 0.00 0 0 sda 426.70 51532.80 0.00 515328 0 sdb 0.00 0.00 0.00 0 0 sdc 0.00 0.00 0.00 0 0 sdd 0.00 0.00 0.00 0 0 Derek - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
