From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: bugzilla-daemon@bugzilla.kernel.org
Cc: linux-scsi@vger.kernel.org
Subject: Re: [Bug 13499] Write cache: disabled, read cache: enabled, supports DPO and FUA? it's bug???
Date: Wed, 10 Jun 2009 14:14:07 +0000 [thread overview]
Message-ID: <1244643247.4109.9.camel@mulgrave.site> (raw)
In-Reply-To: <200906101400.n5AE0rtK002962@demeter.kernel.org>
On Wed, 2009-06-10 at 14:00 +0000, bugzilla-daemon@bugzilla.kernel.org
wrote:
> why Write cache: disabled??
The SCSI mid layer is merely reporting what your array is telling it.
For arrays without a battery backed cache, write through configuration
(i.e. read cache enabled, write cache disabled) is the usual safe
default.
You can alter your write cache settings using Doug Gilbert's
sg3-utils ... but be warned, enabling the write cache without battery
backing in an array is a dangerous thing to do since most arrays have
huge caches, they either ignore SYNCHRONIZE CACHE (which would leave you
vulnerable to data loss on power failure) or take such a long time, it
would kill performance.
James
next prev parent reply other threads:[~2009-06-10 14:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-10 13:59 [Bug 13499] New: Write cache: disabled, read cache: enabled, supports DPO and FUA? it's bug??? bugzilla-daemon
2009-06-10 14:00 ` [Bug 13499] " bugzilla-daemon
2009-06-10 14:14 ` James Bottomley [this message]
2009-06-10 14:14 ` bugzilla-daemon
2009-06-10 17:04 ` bugzilla-daemon
[not found] <bug-13499-11613@https.bugzilla.kernel.org/>
2012-06-08 11:47 ` bugzilla-daemon
2012-06-08 11:47 ` bugzilla-daemon
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