From: Sunil Mushran <sunil.mushran@oracle.com>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [PATCH 1/2] ocfs2: Flush drive's caches on fdatasync
Date: Thu, 29 Jul 2010 19:12:24 -0700 [thread overview]
Message-ID: <4C523508.80802@oracle.com> (raw)
In-Reply-To: <4C5233CB.5000600@oracle.com>
On 07/29/2010 07:07 PM, Tao Ma wrote:
> Hi Jan,
>
> On 07/29/2010 08:00 PM, Jan Kara wrote:
>> We have to issue a cache flush during fdatasync even if inode doesn't
>> have
>> I_DIRTY_DATASYNC set because we still have to get written *data* to
>> disk to
>> observe fdatasync() guarantees.
> I am fine with the patch from the code's perspective.
>
> But I just noticed the discussion in fsdevel with the subject "relaxed
> barrier semantics", so with barrier there will be a massive slowdowns
> according to Christoph. And as ocfs2 is mainly used with some SAN, I
> guess in most cases the storage will have a battery backed cache, so
> we may not need this?
>
> Sunil, Joel and Mark, Did you have any user data that most of the
> ocfs2 system is used on or can we start a survey in ocfs2-users?
A SAN with a battery backed cache is a safe assumption. That's
why we don't enable barrier by default.
next prev parent reply other threads:[~2010-07-30 2:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-29 12:00 [Ocfs2-devel] [PATCH 1/2] ocfs2: Flush drive's caches on fdatasync Jan Kara
2010-07-29 12:00 ` [Ocfs2-devel] [PATCH 2/2] ocfs2: Remove ocfs2_sync_inode() Jan Kara
2010-07-30 2:07 ` [Ocfs2-devel] [PATCH 1/2] ocfs2: Flush drive's caches on fdatasync Tao Ma
2010-07-30 2:12 ` Sunil Mushran [this message]
2010-07-30 14:47 ` Jan Kara
2010-08-02 5:47 ` Tao Ma
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