[pve-devel] Default cache mode for VM hard drives

[Stanislav German-Evtushenko]

On Tue, Nov 18, 2014 at 8:17 PM, Alexandre DERUMIER <aderumier at odiso.com>
wrote:

> >>What is your vm guest os ? kernel version ?
> >>
> >>Guest OS can be Windows (any) and Linux (any version).
>
> I ask the question because old windows virtio driver don't send flush
> correctly,
>
> and some linux kernel too (it's really safe since 2.6.32 - 2.6.33 if I
> remember, depend of filesystem, virtio driver -lvm-mdadm-dm version ..)
> http://monolight.cc/2011/06/barriers-caches-filesystems/
>
> >>2. It is often happen to Linux VM swap space.
> mmm,good point, I don't known how flush is working with swap


graylog2 was installed on Ubuntu 14.04 (virtio as I remember, not checked
with ide)

However:
1) moving to IDE didn't help for Windows
2) moving to IDE can't help for swap
3) I don't remember if I tried ext4 in combination with ide because ext4
didn't produce any issues before I installed graylog2 recently. However
there were many issues with ext3 (no barriers by default)

Stanislav
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