Date: Sun, 20 Jul 2014 23:49:55 -0400 From: Nikolai Lifanov <lifanov@mail.lifanov.com> To: Steven Hartland <killing@multiplay.co.uk> Cc: svn-src-head@freebsd.org, src-committers@freebsd.org, Xin LI <delphij@freebsd.org> Subject: Re: svn commit: r268855 - in head: cddl/contrib/opensolaris/cmd/ztest sys/cddl/contrib/opensolaris/uts/common/fs/zfs sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys Message-ID: <1048c8cc25685b1216b0f1714c4494f1@mail.lifanov.com> In-Reply-To: <09AF6051EC3848B6B691A5570B5B065E@multiplay.co.uk> References: <201407182041.s6IKffMR077972@svn.freebsd.org> <5d0810f5950150ef60044acf239adb4a@mail.lifanov.com> <09AF6051EC3848B6B691A5570B5B065E@multiplay.co.uk>
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On 2014-07-20 22:56, Steven Hartland wrote: > ----- Original Message ----- From: "Nikolai Lifanov" > <lifanov@mail.lifanov.com> > To: "Xin LI" <delphij@freebsd.org> > Cc: <src-committers@freebsd.org>; <svn-src-head@freebsd.org> > Sent: Monday, July 21, 2014 2:22 AM > Subject: Re: svn commit: r268855 - in head: > cddl/contrib/opensolaris/cmd/ztest > sys/cddl/contrib/opensolaris/uts/common/fs/zfs > sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys > > >> On 2014-07-18 16:41, Xin LI wrote: >>> Author: delphij >>> Date: Fri Jul 18 20:41:40 2014 >>> New Revision: 268855 >>> URL: http://svnweb.freebsd.org/changeset/base/268855 >>> >>> Log: >>> MFV r268848: >>> >>> Instead of asserting all zio's be properly aligned, only assert >>> on the logical ones. >>> >>> Cap uberblocks at 8k, otherwise with ashift=17, there would be >>> only one uberblock. >>> >>> This fixes a problem that zdb would trip assert on pools with >>> ashift >= 0xe (8k). >>> >>> While there, also change the code so it only attempt to condense >>> space map unless the uncondensed size consumes greater than >>> zfs_metaslab_condense_block_threshold blocks. >>> >>> Illumos issue: >>> 4958 zdb trips assert on pools with ashift >= 0xe >>> >>> MFC after: 2 weeks >>> >> >> This specific commit makes boot hang just before mounting the root >> dataset for me when vfs.zfs.vdev.cache.size tunable is set. Unsetting >> this tunable or reverting this commit (currently running r268933 minus >> r268855) fixes the boot for me. >> >> Please let me know if I can provide any more information. > > Interesting, is there a reason you enabled vdev caching as its been > disabled by default for quite some time with the comment: > > * TODO: Note that with the current ZFS code, it turns out that the > * vdev cache is not helpful, and in some cases actually harmful. It > * is better if we disable this. Once some time has passed, we should > * actually remove this to simplify the code. For now we just disable > * it by setting the zfs_vdev_cache_size to zero. Note that Solaris 11 > * has made these same changes. > > Regards > Steve > > _______________________________________________ > svn-src-head@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/svn-src-head > To unsubscribe, send any mail to "svn-src-head-unsubscribe@freebsd.org" I noticed that it was disabled on default and I'm not seeing any ill effect now that I have it disabled. I don't find vdev cache beneficial, but I had it in my loader.conf for some time, and I had to remove it to get the system to boot. If it's going to be broken going forward, perhaps it's worthwhile to just remove the tunable? - Nikolai Lifanov
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