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Date: Mon, 12 May 2008 23:57:51 +0800
From: "Rong-en Fan" <grafan@gmail.com>
To: "Scott Long" <scottl@samsco.org>
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Cc: freebsd-scsi@freebsd.org
Subject: Re: default setting of WCE
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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
>