Gary, How full is the pool ?
-- Sanjeev On Sun, Apr 12, 2009 at 08:39:03AM -0500, Gary Mills wrote: > We're running a Cyrus IMAP server on a T2000 under Solaris 10 with > about 1 TB of mailboxes on ZFS filesystems. Recently, when under > load, we've had incidents where IMAP operations became very slow. The > general symptoms are that the number of imapd, pop3d, and lmtpd > processes increases, the CPU load average increases, but the ZFS I/O > bandwidth decreases. At the same time, ZFS filesystem operations > become very slow. A rewrite of a small file can take two minutes. > > We've added memory; this was an improvement, but the incidents > continued. The next step is to disable ZFS prefetch and test this > under load. If that doesn't help either, we're down to ZFS bugs. > > Our incidents seem similar to the ones at UC Davis: > > http://vpiet.ucdavis.edu/docs/EmailReviewCmte.Report_Feb2008.pdf > > These were attributed to bug 6535160, but this one is fixed on our > server with patch 127127-11. Bug 6535172, ``zil_sync causing long > hold times on zl_lock'', doesn't have a patch yet: > > http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6535172 > > Could this bug cause our problem? How do I confirm that it does? > Is there a workaround? > > Cyrus IMAP uses several moderate-sized databases that are > memory-mapped by all processes. I can move these from ZFS to UFS if > this is likely to help. > > -- > -Gary Mills- -Unix Support- -U of M Academic Computing and Networking- > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss -- ---------------- Sanjeev Bagewadi Solaris RPE Bangalore, India _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
