Date: Sun, 22 Aug 2010 18:26:40 +0200 From: Martin Matuska <mm@FreeBSD.org> To: Olivier Smedts <olivier@gid0.org> Cc: freebsd-current@freebsd.org Subject: Re: [CFT] Improved ZFS metaslab code (faster write speed) Message-ID: <4C714FC0.90005@FreeBSD.org> In-Reply-To: <AANLkTi=8x1EenWyqGz6AQWKDUq5JiMJbX_jbVbX43DKx@mail.gmail.com> References: <4C713EF5.8080402@FreeBSD.org> <AANLkTi=8x1EenWyqGz6AQWKDUq5JiMJbX_jbVbX43DKx@mail.gmail.com>
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Thank you, I have updated the v15 patch for 8-STABLE. Dňa 22. 8. 2010 17:44, Olivier Smedts wrote / napísal(a): > 2010/8/22 Martin Matuska <mm@freebsd.org>: >> Dear FreeBSD community, >> >> many of our [2] (and Solaris [3]) users today are complaining about slow >> ZFS writes. One of the causes for these writes is the selection of the >> proper allocation method for allocation of new blocks [3] [4]. Another >> issue a write slowdown during TXG sync times. >> >> Solaris 10 (and OpenSolaris up to november 2009) have the >> following scenario: >> >> - pool has more than 30% free space: use first fit method [1] >> - pool has less than 30% free space: use best fit method [1] >> >> This causes a major slowdown of the writes if we go below 30% of free >> space. On large pools, 30% may be terabytes of free space. >> >> OpenSolaris has changed this in November 2009 and the Oracle Storage >> Appliances also included the new code in Q1/2010 [1]. >> >> The source [1] states, that with this change they archieved a speedup >> of: "50% Improved OLTP Performance, 70% Reduced Variability, 200% >> Improvement on MS Exchange" >> >> I would like to issue a Call For Testing for the following 9-CURRENT patch: >> http://people.freebsd.org/~mm/patches/zfs/zfs_metaslab.patch >> >> To apply the patch against 8-STABLE, you need to apply the v15 update first: >> http://people.freebsd.org/~mm/patches/zfs/v15/stable-8-v15.patch > This one doesn't apply cleanly since few minutes : > # svn log -l 1 sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c > ------------------------------------------------------------------------ > r211599 | avg | 2010-08-22 10:18:32 +0200 (Dim 22 aoû 2010) | 7 lignes > > Fix a mismerge in r211581, MFC of r210427 > > This is a direct commit. > > Reported by: many > Pointyhat to: avg > > ------------------------------------------------------------------------ > > But it does not seem hard to correct. Do you want me to submit an > updated patch for 8-stable ? > >> The patch includes the following OpenSolaris onnv revisions: >> 10921 (partial), 11146, 11728, 12047 >> >> And covers the following Bug IDs: >> 6826241 Sync write IOPS drops dramatically during TXG sync >> 6869229 zfs should switch to shiny new metaslabs more frequently >> 6917066 zfs block picking can be improved >> 6918420 zdb -m has issues printing metaslab statistics >> >> References: >> [1] http://blogs.sun.com/roch/entry/doubling_exchange_performance >> [2] http://forums.freebsd.org/showthread.php?t=8270 >> [3] >> http://blogs.everycity.co.uk/alasdair/2010/07/zfs-runs-really-slowly-when-free-disk-usage-goes-above-80/ >> [4] http://blogs.sun.com/bonwick/entry/zfs_block_allocation >> [5] http://blogs.sun.com/bonwick/entry/space_maps >> _______________________________________________ >> freebsd-current@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-current >> To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >> > >
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