Re: [Qemu-devel] Storage requirements for live migration

[Ryan Harper]

> == 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
address@hidden