Date: Mon, 28 Dec 2009 09:21:11 +0100 From: "Johan Hendriks" <Johan@double-l.nl> To: "David P. Discher" <dpd@bitgravity.com> Cc: freebsd-current@FreeBSD.org Subject: RE: 8.0-RELEASE: disk IO temporarily hangs up (ZFS or ATA relatedproblem) Message-ID: <57200BF94E69E54880C9BB1AF714BBCBA573F9@w2003s01.double-l.local> References: <39309F560B98453EBB9AEA0F29D9D80E@vosz.local><3bbf2fe10912181004w2a1abff2re8f77fd6a8bc3233@mail.gmail.com><FECE64D8325144AD8E65DF1F1D1B0D35@vosz.local> <DEF95B1B-DBF9-4DC7-BEFF-4D8518D23601@bitgravity.com>
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> >ZFS will write buffer ALOT. Your settings of vfs.zfs.arc_min and vfs.zfs.arc_max will likely affect how bursty this >is. I've been running with Min, 32 GB arc, and see very bursty writes (of course, my systems have 64GB).=20 >Also, use 'zpool iostat 1' and not the system iostat. Check gstat as well. >also try using CAM_ATA (ahci.ko) instead of ad devices, so your can get the benefits of tag queuing. >There is also a possible undocumented issue with, I believe it was the WD green drives, where the vibration of the >drive actually slowed it down. This was demonstrated by setting a pound or two of silly putty on the top of the >drive, and its performance (significantly) increased. Experiment with putting some heavily, non-conductive weight on >top of each drive - a book or something.=20 Even with hardware the FreeBSD Handbook comes Handy ;-)=20 > ensure that is its securely mounted as well.=20 >--- >David P. Discher >dpd@bitgravity.com * AIM: bgDavidDPD >BITGRAVITY * http://www.bitgravity.com >On Dec 18, 2009, at 12:04 PM, Alexander Zagrebin wrote: >>>> The disks are used for mirrored ZFS pool. >>>> I have noticed that the system periodically locks up on=20 >>> disk operations. >>>> After approx. 10 min of very slow disk i/o (several KB/s)=20 >>> the speed of disk >>>> operations restores to normal. >>>> gstat has shown that the problem is in ad6. >>>=20 >>> Want you try this patch and report?: >>> http://people.freebsd.org/~attilio/lockmgr_lostwake.diff >>>=20 >>> It should apply to STABLE_8 and if not, just report and I will help. >>=20 >> Thanks fo your attempt to help! >> I've successfully applied this patch to RELENG_8_0, recompiled >> kernel and required modules (krpc, opensolaris,zfs), >> but nothing has changed. The problem still exist. >>=20 >> --=20 >> Alexander Zagrebin >>=20 >> _______________________________________________ >> 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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