On Mar 30, 2009, at 13:48, Michael Shadle wrote:
My only question is is how long it takes to resilver... Supposedly
the entire array has to be checked which means 6x1.5tb. It has a
quad core CPU that's basically dedicated to it. Anyone have any
estimates?
Sounds like it is a lot slower than a normal raid5 style rebuild. Is
there a way to tune it so it can rebuild/resilver faster?
There is a background process in ZFS (see "scrub" in zpool(1M)) that
goes through and make sure all the checksums match reality (and
corrects things if it can). It's reading all the data, but unlike
hardware RAID arrays, it only checks the actual space used.
It basically goes through the file system structure hierarchy, and if
there's an unused space on the array it doesn't bother--since no data
blocks point to it, there's nothing to check. The scrubbing process is
the same whether you're using mirrors, RAID-Z1, or RAID-Z2. It can be
kicked off manually or you can launch it via cron / SMF.
Not sure about tuning (e.g., allocating bandwidth / priority). If you
start a scrub the output of "zpool status" will give the progress (%)
and ETA to finish.
There is (was?) a bug where creating a new snapshot reset the scrub.
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
