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Date: Fri, 29 Mar 2013 00:45:08 +0100
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Subject: Re: [Qemu-devel] [PATCH] Make guest OS bootable when hardware
 failure happens in log disk
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To: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: "kwolf@redhat.com" <kwolf@redhat.com>, "peter.maydell@linaro.org" <peter.maydell@linaro.org>, "aliguori@us.ibm.com" <aliguori@us.ibm.com>, "mst@redhat.com" <mst@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "dle-develop@lists.sourceforge.net" <dle-develop@lists.sourceforge.net>, "hdegoede@redhat.com" <hdegoede@redhat.com>, "kraxel@redhat.com" <kraxel@redhat.com>, Tomoki Sekiyama <tomoki.sekiyama@hds.com>, "afaerber@suse.de" <afaerber@suse.de>

Il 28/03/2013 20:43, Seiji Aguchi ha scritto:
> [Problem]
> Currently, guest OS's messages can be logged to a local disk of host OS by creating chadevs with options below.
>   -chardev file,id=charserial0,path=<log file's path> -device isa-serial,chardev=chardevserial0,id=serial0
> 
> When a hardware failure happens in the disk, qemu-kvm can't create the chardevs.
> In this case, guest OS doesn't boot up.
> 
> Actually, there are users who don't desire that guest OS goes down due to a hardware failure of a log disk only.
> Therefore, qemu should offer some way to boot guest OS up even if the log disk is broken.
> 
> [Solution]
> This patch skips error checks in case where opening a log file and creating chardev fail.

This kind of policy does not belong in QEMU.  QEMU should always fail if
it sees a problem.

Your management tool should just open the file outside QEMU, and then
use either /dev/fd/NN or /dev/null as the destination.

Paolo