From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stefan Hajnoczi <stefanha@gmail.com>
Subject: Re: How to get the real device in guest os after attached a disk?
Date: Tue, 17 Jul 2012 12:56:15 +0100
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References: <1936723074.42171.1342496460585.JavaMail.hzwangpan@corp.netease.com>
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Cc: kvm <kvm@vger.kernel.org>, Ryan Harper <ryanh@linux.vnet.ibm.com>,
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To: Wangpan <hzwangpan@corp.netease.com>
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On Tue, Jul 17, 2012 at 4:40 AM, Wangpan <hzwangpan@corp.netease.com> wrote:
> I have a question as the subject above, the reason I want to know this is that, if I attach some disks on the guest,
> for example, I specified /dev/vdc&/dev/vdd(target device) at the cmd line by using 'virsh attach-disk', but they may be /dev/vdb&/dev/vdc in the guest os,
> so if the guest user want to detach the /dev/vdb(guest device), he\she will be confused with the two target devices /dev/vdb&/dev/vdc,
> because he\she doesn't know the corresponding relation of the guest device and target device,
> he\she may detach an error device /dev/vdd(target device) which corresponding to /dev/vdc(guest device).
>
> Could anyone give me some idea?

You can use the virtio-blk serial or file system/volume labels to
distinguish them.

For libvirt disk <serial> information, see the Domain XML documentation:
http://libvirt.org/formatdomain.html#elementsDisks

Stefan