From: jim owens <jowens@hp.com>
To: Jamie Lokier <jamie@shareable.org>
Cc: Chris Mason <chris.mason@oracle.com>,
Theodore Tso <tytso@mit.edu>, Nick Piggin <npiggin@suse.de>,
linux-fsdevel@vger.kernel.org, Eric Sandeen <sandeen@sandeen.net>
Subject: Re: [rfc] fsync_range?
Date: Wed, 21 Jan 2009 16:23:58 -0500 [thread overview]
Message-ID: <4977926E.30703@hp.com> (raw)
In-Reply-To: <20090121204105.GA16133@shareable.org>
Jamie Lokier wrote:
>
> Does O_DIRECT on btrfs still allocate new data blocks?
> That's not very direct :-)
>
> I'm thinking if O_DIRECT is set, considering what's likely to request
> it, it may be reasonable for it to mean "overwrite in place" too
> (except for files which are actually COW-shared with others of course).
O_DIRECT for databases is to bypass the OS file data cache.
Those (oracle) who have long experience with it on unix
know that the physical storage location can change on
a filesystem.
I do not think we want to make a special case,
it should be up to the db admin to choose cow/nocow
because if they want SNAPSHOTS they need cow.
jim
next prev parent reply other threads:[~2009-01-21 21:24 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 16:47 [rfc] fsync_range? Nick Piggin
2009-01-20 18:31 ` Jamie Lokier
2009-01-20 21:25 ` Bryan Henderson
2009-01-20 22:42 ` Jamie Lokier
2009-01-21 19:43 ` Bryan Henderson
2009-01-21 21:08 ` Jamie Lokier
2009-01-21 22:44 ` Bryan Henderson
2009-01-21 23:31 ` Jamie Lokier
2009-01-21 1:36 ` Nick Piggin
2009-01-21 19:58 ` Bryan Henderson
2009-01-21 20:53 ` Jamie Lokier
2009-01-21 22:14 ` Bryan Henderson
2009-01-21 22:30 ` Jamie Lokier
2009-01-22 1:52 ` Bryan Henderson
2009-01-22 3:41 ` Jamie Lokier
2009-01-21 1:29 ` Nick Piggin
2009-01-21 3:15 ` Jamie Lokier
2009-01-21 3:48 ` Nick Piggin
2009-01-21 5:24 ` Jamie Lokier
2009-01-21 6:16 ` Nick Piggin
2009-01-21 11:18 ` Jamie Lokier
2009-01-21 11:41 ` Nick Piggin
2009-01-21 12:09 ` Jamie Lokier
2009-01-21 4:16 ` Nick Piggin
2009-01-21 4:59 ` Jamie Lokier
2009-01-21 6:23 ` Nick Piggin
2009-01-21 12:02 ` Jamie Lokier
2009-01-21 12:13 ` Theodore Tso
2009-01-21 12:37 ` Jamie Lokier
2009-01-21 14:12 ` Theodore Tso
2009-01-21 14:35 ` Chris Mason
2009-01-21 15:58 ` Eric Sandeen
2009-01-21 20:41 ` Jamie Lokier
2009-01-21 21:23 ` jim owens [this message]
2009-01-21 21:59 ` Jamie Lokier
2009-01-21 23:08 ` btrfs O_DIRECT was " jim owens
2009-01-22 0:06 ` Jamie Lokier
2009-01-22 13:50 ` jim owens
2009-01-22 21:18 ` Florian Weimer
2009-01-22 21:23 ` Florian Weimer
2009-01-21 3:25 ` Jamie Lokier
2009-01-21 3:52 ` Nick Piggin
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