Re: [Qemu-devel] qcow2 - safe on kill? safe on power fail?

[Jamie Lokier]

Avi Kivity wrote:
> The exposure window with qemu is not small.  It's as large as the page 
> cache of the host.

Ouch, that's a good point.  I hadn't thought of that.

With cache=off, the exposure window is as large as the I/O scheduling
and disk seek time between the multiple blocks written during sector
allocation.  Given how often sector allocation occurs, it's not small.

I think I'm going to just stop using QCOW2, bite the bullet, and use
large disks and flat images for all production VMs.

The small but looking-plausible possibility of losing a whole valuable
machine due to niggling things like a rare QEMU crash or host crash is
very uncool.

-- Jamie