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
