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From: Anthony Roberts <btrfs-devel@arbitraryconstant.com>
To: Chris Mason <chris.mason@oracle.com>
Cc: Dmitri Nikulin <dnikulin@gmail.com>,
	linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: btrfs and swap files on SSD's ?
Date: Tue, 20 Jan 2009 09:35:02 -0700	[thread overview]
Message-ID: <f45c907a12e473689f0061d68c4e0749@smtp.arbitraryconstant.com> (raw)
In-Reply-To: <1232461902.15042.19.camel@think.oraclecorp.com>

> The second is an implementation detail of the linux swap file code.  It
> expects filesystems don't move blocks around, and takes a mapping of the
> blocks in the FS once.
> 
> This doesn't work with btrfs because we do move blocks around all the
> time.

That's interesting. I have a few questions:

-Is creating a loopback device from the file any different, or does that
lead to the same problems?

-Would mounting a filesystem image via loopback device cause similar
problems?

-Would this be viable if using a dedicated nodatacow subvolume, or is that
still too risky because of the odd case where you do cow?

-Does online defragmentation hurt this as well?

Cheers,

-Anthony


  reply	other threads:[~2009-01-20 16:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-17  0:10 btrfs and swap files on SSD's ? Chris Samuel
2009-01-19 16:22 ` Chris Mason
2009-01-20 10:41   ` Kaspar Schleiser
2009-01-20 13:02     ` Chris Mason
2009-01-20 13:51       ` Dmitri Nikulin
2009-01-20 14:31         ` Chris Mason
2009-01-20 16:35           ` Anthony Roberts [this message]
2009-01-20 16:41             ` Chris Mason
2009-01-21  6:15         ` Andi Kleen

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