Date: Wed, 1 Nov 2006 00:54:26 +0100 From: Wilko Bulte <wb@freebie.xs4all.nl> To: Fredrik Widlund <fredrik.widlund@qbrick.com> Cc: freebsd-stable@freebsd.org, Ivan Voras <ivoras@fer.hr> Subject: Re: SAS Raid - mfi driver Message-ID: <20061031235425.GA12218@freebie.xs4all.nl> In-Reply-To: <4547DD7E.4030509@qbrick.com> References: <45470D95.5020801@qbrick.com> <ei7448$4rs$1@sea.gmane.org> <454718DD.8060108@qbrick.com> <45471ACC.2030604@fer.hr> <4547421D.2010206@qbrick.com> <45477FCC.9050901@qbrick.com> <ei8hus$jec$1@sea.gmane.org> <4547DD7E.4030509@qbrick.com>
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On Wed, Nov 01, 2006 at 12:34:22AM +0100, Fredrik Widlund wrote.. > Yes, it forces writeback even when the controller has no BBU. Choosing > WBack itself will default back to WThru. It's dangerous, but I guess it > should be much less dangerous than using for example softupdates. We > have little choice until our order of BBUs get here, since the > performance degradation of wthru would make it unusable for us. At least hook the machine up to an UPS if you have one. > Ivan Voras skrev: > >Fredrik Widlund wrote: > > > >>Solved my issue with LSI 8480E without BBU. With "write: BadBBU", > >>"cache: enabled", and "io: cached", performance rose to around 200MB/s > >>from 20MB/s. > >> > > > >I don't know what "BadBBU" is, but from some Googling it seems to be a > >setting that overrides BBU detection, and enables write caching even if > >the system believes BBU is broken or missing. If true, this may be > >dangerous for data consistency. > > > >_______________________________________________ > >freebsd-stable@freebsd.org mailing list > >http://lists.freebsd.org/mailman/listinfo/freebsd-stable > >To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" --- end of quoted text --- -- Wilko Bulte wilko@FreeBSD.org
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