From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Gionatan Danti <g.danti@assyoma.it>, linux-xfs@vger.kernel.org
Subject: Re: Disabling barriers on NVC-backed HDD
Date: Wed, 15 Nov 2017 11:47:00 -0800 [thread overview]
Message-ID: <20171115194700.GA6228@infradead.org> (raw)
In-Reply-To: <20171115173100.GD5119@magnolia>
On Wed, Nov 15, 2017 at 09:31:00AM -0800, Darrick J. Wong wrote:
> I would evaluate these drives to find out if you really /can/ yank the
> power without losing anything.
>
> That said, if the manufacturers aren't willing to tell you how that
> feature works, I'd just as soon pretend the feature didn't exist and
> continue sending flushes to the drive.
>
> FWIW if the drive really /does/ have a non-volatile WC then a flush
> should have nearly zero overhead. (Or so you'd think...)
And in that case it will report WCE=0 and Linux won't even flush.
As is the case for typical enterprise disks.
next prev parent reply other threads:[~2017-11-15 19:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-15 17:01 Disabling barriers on NVC-backed HDD Gionatan Danti
2017-11-15 17:31 ` Darrick J. Wong
2017-11-15 18:53 ` Gionatan Danti
2017-11-15 19:47 ` Christoph Hellwig [this message]
2017-11-15 20:17 ` Gionatan Danti
2017-11-15 20:18 ` Gionatan Danti
2017-11-15 20:27 ` Gionatan Danti
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