Re: [Qemu-devel] [PATCH] Make guest OS bootable when hardware failure happens in log disk

[Paolo Bonzini]

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