Quoting Fabian Keil <freebsd-listen_at_fabiankeil.de> (from Thu, 3 Mar 2011 13:01:30 +0100): > Alexander Leidinger <Alexander_at_Leidinger.net> wrote: > >> On Mon, 28 Feb 2011 19:21:29 +0100 Fabian Keil >> <freebsd-listen_at_fabiankeil.de> wrote: >> >> > Pawel Jakub Dawidek <pjd_at_FreeBSD.org> wrote: >> > >> > > I just committed ZFSv28 to HEAD. >> > >> > I updated the system without removing the tuning for ZFSv15 >> > first, and somehow this completely messed up the performance. >> > Booting the system took more than ten minutes and even once >> > it was up it was next to unresponsive. >> > >> > I'm not sure which sysctl was to blame, but after removing >> > all but vfs.zfs.arc_max="800M" and rebooting, the problem >> > was gone. >> >> When you add the tuning back, does it take minutes again to boot? If >> not, I assume it was cleaning up some leftovers the old version was not >> able to cleanup. > > I haven't tried that yet, but as I didn't upgrade the system's > storage pool I don't think ZFS is supposed to do any such clean-ups. AFAIK the new code knows how to remove some superfluous parts in your pool (no matter at which version the pool is), which the old code just skipped over. Such leftovers may not be in all pools, they show up just in some use cases. For this reason I asked to verify by adding the tuning back to this system (if possible). If it is not a production-like system which does not accept downtime, this verification consumes less resources than sending out a developer hunting for a problem which may not even exist. Bye, Alexander. -- A short cut is the longest distance between two points. http://www.Leidinger.net Alexander _at_ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild _at_ FreeBSD.org : PGP ID = 72077137Received on Thu Mar 03 2011 - 11:52:13 UTC
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