Re: [Qemu-devel] [PATCH] bdrv_flush error handling

[Jamie Lokier <jamie@shareable.org>]

Ian Jackson wrote:
> Paul Brook writes ("Re: [Qemu-devel] [PATCH] bdrv_flush error handling"):
> > Disk full is a fundamentally unfriendly situation to be in. There is no good 
> > answer. Reporting errors back to the host has its own set of problems. Many 
> > guest OS effectively just lock up when this occurs.
> 
> I think that's fine, surely ?  A locked up guest isn't very nice but
> it's better than a guest shot dead.

Well, a guest which receives an IDE write error might do things like
mark parts of the device bad, to avoiding writing to those parts.  If
the guest is running software RAID, for example, it will radically
change its behaviour in response to those errors.

Sometimes that's what you want, but sometimes it is really unwanted.
If the host runs out of disk space, ideally you might want to suspend
the guest until you can free up host disk space (or move to another
host), then resume the guest, perhaps manually.

Is savevm-upon-disk-full a realistic prospect?

-- Jamie