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From: Jamie Lokier <jamie@shareable.org>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] qcow2 - safe on kill?  safe on power fail?
Date: Tue, 22 Jul 2008 15:32:43 +0100	[thread overview]
Message-ID: <20080722143242.GC20829@shareable.org> (raw)
In-Reply-To: <488578CA.4000402@qumranet.com>

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

  parent reply	other threads:[~2008-07-22 14:10 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-05 21:18 [Qemu-devel] Signal handling and qcow2 image corruption David Barrett
2008-03-05 21:55 ` Anthony Liguori
2008-03-05 23:48   ` David Barrett
2008-03-06  6:57   ` Avi Kivity
2008-07-21 18:10   ` [Qemu-devel] qcow2 - safe on kill? safe on power fail? Jamie Lokier
2008-07-21 19:43     ` Anthony Liguori
2008-07-21 21:26       ` Jamie Lokier
2008-07-21 22:14         ` Anthony Liguori
2008-07-21 23:47           ` Jamie Lokier
2008-07-22  6:06           ` Avi Kivity
2008-07-22 14:08             ` Anthony Liguori
2008-07-22 14:46               ` Jamie Lokier
2008-07-22 19:11               ` Avi Kivity
2008-07-22 14:32             ` Jamie Lokier [this message]
2008-07-21 22:00       ` Andreas Schwab
2008-07-21 22:15         ` Anthony Liguori
2008-07-21 22:22           ` David Barrett
2008-07-21 22:50             ` Anthony Liguori
2008-07-22  6:07           ` Avi Kivity
2008-07-22 14:11             ` Anthony Liguori
2008-07-22 14:36               ` Avi Kivity
2008-07-22 16:16                 ` Jamie Lokier
2008-07-22 19:13                   ` Avi Kivity
2008-07-22 20:04                     ` Jamie Lokier
2008-07-22 21:25                       ` Avi Kivity
2008-07-22 14:22             ` Jamie Lokier

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