Re: Issues with KVM

[Victor Stinner <victor.stinner@haypocalc.com>]

Hi,

Le 22/07/2011 21:59, C Anthony Risinger a =C3=A9crit :
> ) is the host FS btrfs?
The host (Fedora) FS is btrfs, the VM (Debian) uses ext4 (or maybe ext3=
,=20
I will have to check).
> ) are virtio modules in the initramfs (or kernel probably)?
> ) are you sure virtio is being used (eg. are the disks called vdX vs =
sdX)?
> ) is the disk bus set to virtio (virtmanager)?
I'm not sure. I will have to check.
> ) is the disk's cache mode set to none [or maybe writeback] (virtmana=
ger)?
I don't remember, I will check.

What is the effect of this option? (What is the effect on the host FS=20
(btrfs)?)
> ) is the disk's storage format set to "raw", should be (virtmanager)?
Yes, the image type is "raw".
> ) is caching enabled on the image? ()
What do you mean? Is it possible to enable or disable the cache on a=20
specific file on the host (Fedora, btrfs)? Or you mean set cache to non=
e=20
in the configuration of the VM?
> probably need to change the cache mode on the disk, or if the host is
> btrfs you need to flag the image with whetever is needed to prevent
> continuous COWing.
Can nodatacow option of btrfs have an effect on this issue? Is it=20
possible to set this option for a specific file or directory?

Victor

PS: I have subscribed to the mailing list.

PS2: I'm not at home this week-end, I will check monday.
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