Date: Thu, 17 Jan 2013 13:52:41 +0100 From: Fabian Keil <freebsd-listen@fabiankeil.de> To: Eitan Adler <lists@eitanadler.com> Cc: questions@freebsd.org Subject: Re: absurd I/O perf with ZFS: hangs on zfs->cv) Message-ID: <20130117135241.434f273a@fabiankeil.de> In-Reply-To: <CAF6rxgkCWC_HopEWqhMKw245itPXKJbn4_DD66NKiD1di8ysWw@mail.gmail.com> References: <CAF6rxgkJr7xrmZkkp0eH_-WzuvdmCBDwPPOZFoqWUZ2jqXqneg@mail.gmail.com> <CAF6rxgkCWC_HopEWqhMKw245itPXKJbn4_DD66NKiD1di8ysWw@mail.gmail.com>
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--Sig_/0qhbqe.9JK+i+Gc+PyWLjzb Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Eitan Adler <lists@eitanadler.com> wrote: > On 15 January 2013 23:57, Eitan Adler <lists@eitanadler.com> wrote: > > Running FreeBSD 9.1-Release, I am seeing some absurd hangs (10 minutes > > or more to open a file) with SIGINFO informing me that the process is > > stuck on zio->io_cv. > > > > Does anyone have any suggestions for what I want to look at to tune > > this? This is on a newly bought laptop with large amounts of RAM and > > almost nothing else running. I don't think there are any laptops with "large amounts of RAM" as far as ZFS is concerned. > It is taking me 45 minutes to make 5 commits to git. Something is > wrong here but I have no idea what I should be looking at. Any ideas? Try sysutils/zfs-stats to get a rough idea of how ZFS is using the available memory. If you already followed tuning advice from the Internet without benchmarking it, try reverting it. In my experience some of the tunables that helped or at least didn't hurt with earlier ZFS versions make things significantly worse with ZFSv28 and later: http://lists.freebsd.org/pipermail/freebsd-fs/2011-March/010860.html Once you have gathered some more information it might make sense to ask again on freebsd-fs@. On a new system it's probably not an issue, but the recommendation is to keep around 20% of the pool free to keep the performance up. Fabian --Sig_/0qhbqe.9JK+i+Gc+PyWLjzb Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlD39CIACgkQBYqIVf93VJ2XqQCeN+NmYc4sRkaUNY1hjM3ozcwx eoUAnj5v/C/WAYah/DSv/lYV3rwheDpI =Yz2f -----END PGP SIGNATURE----- --Sig_/0qhbqe.9JK+i+Gc+PyWLjzb--
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