|
From: | Paul Brook |
Subject: | Re: [Qemu-devel] [PATCH v2] make windows notice media change |
Date: | Wed, 29 Jul 2009 20:52:35 +0100 |
User-agent: | KMail/1.11.4 (Linux/2.6.29-2-amd64; KDE/4.2.4; x86_64; ; ) |
> >>> Why shouldn't we support loading version 2 snapshots? Afterall that's > >>> why we had the versioning in the first place. > >> > >> No it's not. Versioning was introduced to *prevent* loading old > >> snapshots and crashing or ending up with inconsistent guest state. I'm > >> still unconvinced that anything other than very short term backward > >> compatibility is worthwhile or even viable. > > > > I see it as a way to migrate a running guest to newer QEMU version, > > possibly even with live migration. In fact I used it quite often back in > > the day when snapshots were not part of qcow2 yet and when kqemu was > > still in its heydays. > > BTW, why would there be the version parameter in the first place if it > wasn't supposed to load older versions?! Like I already said: it's there to prevent an old version being loaded accidentally. Without this an incompatible change will result in anything from a crash to corrupt/inconsistent guest state. Versioning allows us to reject the snapshot and fail safely. Paul
[Prev in Thread] | Current Thread | [Next in Thread] |