From: Ryan Harper <ryanh@us.ibm.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Kevin Wolf <kwolf@redhat.com>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
Juan Quintela <quintela@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] Storage requirements for live migration
Date: Fri, 11 Nov 2011 16:43:18 -0600 [thread overview]
Message-ID: <20111111224318.GC6036@us.ibm.com> (raw)
In-Reply-To: <4EBC683C.7090700@codemonkey.ws>
> == Image Formats ==
>
> Image formats are not safe to use with live migration. The reason is that
> QEMU caches data for image formats and does not have a mechanism to flush
> those caches. The following attempts to describe the issues with the
> various formats
>
> === QCOW2 ===
>
> QCOW2 caches two forms of data, cluster metadata (L1/L2 data, refcount
> table, etc) and mutable header information (file size, snapshot entries,
> etc).
>
> This data needs to be discarded before after migration starts.
before after?
pick one =)
--
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
ryanh@us.ibm.com
next prev parent reply other threads:[~2011-11-11 22:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-11 0:11 [Qemu-devel] Storage requirements for live migration Anthony Liguori
2011-11-11 6:27 ` Mark Wu
2011-11-11 9:15 ` Kevin Wolf
2011-11-11 9:38 ` Kevin Wolf
2011-11-11 9:55 ` Daniel P. Berrange
2011-11-11 10:01 ` Kevin Wolf
2011-11-11 14:08 ` Anthony Liguori
2011-11-11 14:05 ` Anthony Liguori
2011-11-11 22:43 ` Ryan Harper [this message]
2011-11-11 23:23 ` Anthony Liguori
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