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Re: [Xen-users] Writing fast in domU crashes entire xen system

To: moncojhr <moncojhr@xxxxxxxxx>
Subject: Re: [Xen-users] Writing fast in domU crashes entire xen system
From: "Fajar A. Nugraha" <list@xxxxxxxxx>
Date: Fri, 18 Feb 2011 18:55:42 +0700
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On Fri, Feb 18, 2011 at 5:58 PM, moncojhr <moncojhr@xxxxxxxxx> wrote:
> Having a problem here where, if I write quickly in a domU, dom0
> freezes up and I cant do anything but reboot, you can still type, just
> nothing will ever do anything.
> I noticed that I am able to get much faster speeds writing in the domU
> then in dom0:
> dom0: 1073741824 bytes (1.1 GB) copied, 27.3189 s, 39.3 MB/s
> domU: 1073741824 bytes (1.1 GB) copied, 6.80832 s, 158 MB/s

That's because dom0 is buffering the writes.

> I do not get the freeze/lockup when writing in dom0, only when writing
> quickly a lot of data in domU.
> I am using file: for my vm's , using the dom0 from git.

Don't use file:.
- tap2:tapdisk:aio: (if you're using Xen >= 4.0.1)
- tap:tapdisk:aio: (if you're using Xen = 4.0.0)
- tap:aio (anything older than 4.0.0)


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