On Tue, Mar 16, 2010 at 3:25 PM, Justin Maggard <jmaggard10@xxxxxxxxx> wrote: > On Tue, Mar 16, 2010 at 2:52 PM, Neil Brown <neilb@xxxxxxx> wrote: >> On Tue, 16 Mar 2010 14:32:55 -0700 >> Justin Maggard <jmaggard10@xxxxxxxxx> wrote: >> >>> I've noticed on recent kernels that /sys/block/md?/md/sync_completed >>> seems to rarely get updated. What is the expected update interval? >>> For me, it seems to only update about once every 6% or so during the >>> resync. Of course, /proc/mdstat has the actual current progress. >> >> The expected update time is every 6% - actually 1/16 which is 6.25%. >> >> sync_completed includes a guarantee that all blocks before this point really >> have been processed. The number in /proc/mdstat is less precise. The much >> of the array has been resynced, but due to the possibility of out-of-order >> completion of writes they may not be a contiguous series of blocks. >> >> Providing the guarantee (which is needed for externally-managed metadata) >> requires briefly stalling the resync, so I didn't want to do it more often. >> I could possibly make it time-bases instead of size-based though. >> >> Is this a problem for you? >> > > Thanks for the info. No, it's not much of a problem, really. Just > seemed strange that an array of 2TB disks could resync for an hour > with no update to sync_completed. I thought I remembered older > kernels updating a lot more frequently, but I could be wrong about > that. So I take it that point is where the resync would resume if the > system was rebooted? > > -Justin > -- > 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 > Rather than a time basis would it be possible to have a sysfs paramater which could be tuned via write? Candidates for this would be something like: sync_flushes_per_action (fractional unit, every 1/N of the device) OR sync_flush_stripes -- 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
