> BTW, now that you're tinkering with ZFS threads and priorities, whould > you by any chance have any idea why zfs scrub is so painfully slow on > -current? > When I start scrub on my -stable box, it pretty much runs full speed > -- I can see disks under load all the time. > However on -current scrub seems to run in small bursts. Disks get busy > for a second or so and then things get quiet for about five seconds or > so and this pattern repeats over and over. This is intentional. The newer ZFS code has, if I remember correctly, something like "spend at most 1/5 of the time doing scrub for each underlying vdev". I could be wrong on the details and I don't have source refs off-hand, by I looked into this when I wanted to see if I could tweak this (while I definitely like it rate limited, I would have liked to up the threshold a bit). My conclusion at the time was that there was no way to tweak it other than recompiling the kernel. -- / Peter Schuller PGP userID: 0xE9758B7D or 'Peter Schuller <peter.schuller_at_infidyne.com>' Key retrieval: Send an E-Mail to getpgpkey_at_scode.org E-Mail: peter.schuller_at_infidyne.com Web: http://www.scode.org
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