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Date: Fri, 11 Nov 2011 17:23:42 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] Storage requirements for live migration
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To: Ryan Harper <ryanh@us.ibm.com>
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>

On 11/11/2011 04:43 PM, Ryan Harper wrote:
>> == 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 =)

Er, the sentence is intelligible with either word.  I've updated the wiki with 
something that actually makes sense :-)

Regards,

Anthony Liguori

>
>