Date: Mon, 12 May 2008 23:57:51 +0800 From: "Rong-en Fan" <grafan@gmail.com> To: "Scott Long" <scottl@samsco.org> Cc: freebsd-scsi@freebsd.org Subject: Re: default setting of WCE Message-ID: <6eb82e0805120857r2e7ff540ub44b3f8661aeba91@mail.gmail.com> In-Reply-To: <48284D18.5010801@samsco.org> References: <6eb82e0805110511l2e814258p4ec1a22145da9477@mail.gmail.com> <48284D18.5010801@samsco.org>
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On Mon, May 12, 2008 at 9:58 PM, Scott Long <scottl@samsco.org> wrote: > Rong-en Fan wrote: >> >> Hi, >> >> I'm wondering what's the default of our da(4) regarding >> the WCE (write cache) bit. I see some of my disks has this >> bit on by default and some are off. I guess it depends on >> the capabilities returned by the underlying device when >> probing? In addition, on the same hardware, I found that >> Linux has write cache enabled by default... (yes, I have read >> da(4) and knows the pros/cons of enabling this). >> > > The 'da' driver leaves the WCE setting alone by default. The > MPT driver does enable the write cache on SATA drives that it > finds on SAS controllers, but this is specific to this driver > and it happens unknown to the da driver. Ok, so it depends on the driver that the disk attached to. Thanks for clarifying. Regards, Rong-En Fan > > Scott >
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