From: Tomasz Chmielewski <mangoo@wpkg.org>
To: Chris Mason <chris.mason@oracle.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: LVM vs btrfs as a "volume manager" for SANs
Date: Fri, 24 Apr 2009 01:34:02 +0200 [thread overview]
Message-ID: <49F0FAEA.2020904@wpkg.org> (raw)
In-Reply-To: <1240512313.28015.14.camel@think.oraclecorp.com>
Chris Mason schrieb:
>> However, with btrfs, I'm not sure about:
>>
>> - what happens if SAN machine crashes while the iSCSI file images were
>> being written to; with LVM and its block devices, I'm somehow more
>> confident it wouldn't make more data loss than necessary
>
> If iscsi is writing with O_DIRECT|O_SYNC it should work.
What if it doesn't?
> But, tuning
> for this config is something we have to concentrate more on.
>
>> - taking snapshots of individual files (file images on SAN) is not
>> possible with btrfs? Probably they would have to be placed in separate
>> directories first to make snapshots - some minor manageability issue
>
> Btrfs can't snapshot a single dir, but it can snapshot a single file.
> See the bcp command included with btrfs-progs.
>
> I'd also suggest using preallocated files (via fallocate) instead of
> sparse files. I will perform better in general.
When performance is needed - sure.
--
Tomasz Chmielewski
http://wpkg.org
next prev parent reply other threads:[~2009-04-23 23:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-22 19:20 LVM vs btrfs as a "volume manager" for SANs Tomasz Chmielewski
2009-04-23 0:13 ` Dmitri Nikulin
2009-04-23 18:45 ` Chris Mason
2009-04-23 23:34 ` Tomasz Chmielewski [this message]
2009-04-24 12:38 ` Chris Mason
2009-07-02 15:22 ` Tomasz Chmielewski
2009-07-06 18:51 ` Chris Mason
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