Date: Fri, 1 Mar 2013 15:27:56 +0400 From: Lev Serebryakov <lev@FreeBSD.org> To: Ivan Voras <ivoras@freebsd.org>, Don Lewis <truckman@FreeBSD.org> Cc: freebsd-fs@freebsd.org, freebsd-geom@freebsd.org Subject: Re: Unexpected SU+J inconsistency AGAIN -- please, don't shift topic to ZFS! Message-ID: <612776324.20130301152756@serebryakov.spb.ru> In-Reply-To: <kgo2hn$f1s$1@ger.gmane.org> References: <1796551389.20130228120630@serebryakov.spb.ru> <1238720635.20130228123325@serebryakov.spb.ru> <1158712592.20130228141323@serebryakov.spb.ru> <CAPJF9w=CZg_%2BK7NHTGUhRLaMJWWNOG7zMipGMJL6w6NoNZpSXA@mail.gmail.com> <583012022.20130228143129@serebryakov.spb.ru> <kgnp1n$9mc$1@ger.gmane.org> <1502041051.20130228185647@serebryakov.spb.ru> <kgo2hn$f1s$1@ger.gmane.org>
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Hello, Ivan. You wrote 28 =D1=84=D0=B5=D0=B2=D1=80=D0=B0=D0=BB=D1=8F 2013 =D0=B3., 21:01= :46: >> One time, Kirk say, that delayed writes are Ok for SU until bottom >> layer doesn't lie about operation completeness. geom_raid5 could >> delay writes (in hope that next writes will combine nicely and allow >> not to do read-calculate-write cycle for read alone), but it never >> mark BIO complete until it is really completed (layers down to >> geom_raid5 returns completion). So, every BIO in wait queue is "in >> flight" from GEOM/VFS point of view. Maybe, it is fatal for journal :( IV> It shouldn't be - it could be a bug. I understand, that it proves nothing, but I've tried to repeat "previous crash corrupt FS in journal-undetectable way" theory by killing virtual system when there is massive writing to geom_radi5-based FS (on virtual drives, unfortunately). I've done 15 tries (as it is manual testing, it takes about 1-1.5 hours total), but every time FS was Ok after double-fsck (first with journal and last without one). Of course, there was MASSIVE loss of data, as timeout and size of cache in geom_raid5 was set very high (sometimes FS becomes empty after unpacking 50% of SVN mirror seed, crash and check) but FS was consistent every time! --=20 // Black Lion AKA Lev Serebryakov <lev@FreeBSD.org>
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