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Re: [Qemu-devel] [PULL 08/17] block: Assert no write requests under BDRV
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-devel] [PULL 08/17] block: Assert no write requests under BDRV_O_INCOMING |
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Date: |
Fri, 19 Feb 2016 15:11:18 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 |
On 19/02/2016 14:47, Kevin Wolf wrote:
> > The problem seems coming from "snapshot=on".
> Aha. The combination of migration with snapshot=on is obvious nonsense
> (because on the destination the disk state would be reverted while the
> guest OS thinks the disk is unchanged),
Not really, on the destination the disk state will not be _further
updated_, but no reversion happens.
Migration with "snapshot=on" makes sense if you are resuming a VM from a
saved checkpoint ("-incoming exec"). You can use it to debug a
migration load, for example, because you want the resumed guest to
always start with the same disk contents. It's somewhat weird, but it
definitely has its uses. A blocker would be a pain in the ass...
Paolo