Matthias Buelow wrote this message on Thu, Jul 14, 2005 at 21:52 +0200: > >The problem is that disks lie about whether they have actually written > >data. If the power goes off before the data is in cache, it's lost. > > No, the problem is that FreeBSD doesn't implement request barriers > and that softupdates is flawed by design and seemingly could not > make use of them, even if they were available (because, as I > understand it, it relies on a total ordering of all writes, unlike > the partial ordering necessary for a journalled fs).
even request barries will not save the fs in a power loss if the track that is getting flushed durning a power loss... Some other FreeBSD folk has a reproducable case of where blocks that were not written to on ATA hardware got trashed after a power loss... With non-written to sectors getting trashed with the cache enabled, barriers don't mean squat... -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not." _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[EMAIL PROTECTED]"