On 3/12/2014 9:49 PM, Adam Goryachev wrote: ... > Number Major Minor RaidDevice State > 7 8 33 0 active sync /dev/sdc1 > 6 8 1 1 active sync /dev/sda1 > 8 8 49 2 active sync /dev/sdd1 > 5 8 81 3 active sync /dev/sdf1 > 9 8 65 4 active sync /dev/sde1 ... > /dev/sda Total_LBAs_Written 845235 > /dev/sdc Total_LBAs_Written 851335 > /dev/sdd Total_LBAs_Written 804564 > /dev/sde Total_LBAs_Written 719767 > /dev/sdf Total_LBAs_Written 719982 ... > So the drive with the highest writes 851335 and the drive with the > lowest writes 719982 show a big difference. Perhaps I have a problem > with the setup/config of my array, or similar? This is normal for striped arrays. If we reorder your write statistics table to reflect array device order, we can clearly see the effect of partial stripe writes. These are new file allocations, appends, etc that are smaller than stripe width. Totally normal. To get these close to equal you'd need a chunk size of 16K or smaller. > /dev/sdc Total_LBAs_Written 851335 > /dev/sda Total_LBAs_Written 845235 > /dev/sdd Total_LBAs_Written 804564 > /dev/sde Total_LBAs_Written 719767 > /dev/sdf Total_LBAs_Written 719982 > So, I could simply do the following: > mdadm --manage /dev/md1 --add /dev/sdb1 > mdadm --grow /dev/md1 --raid-devices=6 > > Probably also need to remove the bitmap and re-add the bitmap. Might want to do ~$ echo 250000 > /proc/sys/dev/raid/speed_limit_min ~$ echo 500000 > /proc/sys/dev/raid/speed_limit_min That'll bump min resync to 250 MB/s per drive, max 500 MB/s. IIRC the defaults are 1 MB/s and 100 MB/s. > Can anyone suggest if what I am seeing is "normal", and should I just go > ahead and add the extra disk? Don't see why not. You might want to stop drbd first. -- Stan -- 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
