Messages in this thread | | | Date | Thu, 16 Jun 2011 09:21:03 +0300 | Subject | Re: [ANNOUNCE] Native Linux KVM tool v2 | From | Pekka Enberg <> |
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On Thu, Jun 16, 2011 at 1:44 AM, Anthony Liguori <anthony@codemonkey.ws> wrote: >>> That's probably why it's fast, it doesn't preserve data integrity :( >> >> Actually, I misread the code. It does unstable writes but it does do >> fsync() on FLUSH.
On Thu, Jun 16, 2011 at 8:41 AM, Pekka Enberg <penberg@kernel.org> wrote: > Yes. That's fine, right? Or did we misread how virtio block devices > are supposed to work?
And btw, we use sync_file_range() to make sure the metadata part of a QCOW2 image is never corrupted. The rational here is that if the guest doesn't do VIRTIO_BLK_T_FLUSH, you can corrupt your _guest filesystem_ but the _image_ will still work just fine and you can do fsck on it.
Also, Prasad ran xfstests and did over-night stress tests to iron out corruption issues. Now we obviously can't promise that we'll never eat your data but I can assure you that we've done as much as we've been able to with the resources we have at the moment.
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