Re: I/O errors after migration - why?

[Tomasz Chmielewski <mangoo@wpkg.org>]

Tomasz Chmielewski schrieb:
> I'm trying to perform live migration by following the instructions on 
> http://www.linux-kvm.org/page/Migration.
> Unfortunately, it doesn't work very well - guest is migrated, but looses 
> access to its disk.
> 
> On the destination host, I'm starting the guest with exactly the same 
> options as on the source host, with "-incoming tcp:0:4444".
> On the source host, I start the migration with "migrate -d tcp:B:4444".
> 
> Both hosts use the same iSCSI device and can access it.
> 
> Looks like the destination host can't really access the iSCSI device 
> after all? No - after I reboot the guest (echo b > /proc/sysrq-trigger), 
> it boots just fine from its disk. Also lsof on the host shows that the 
> kvm process accesses the correct /dev/sdX device.

Similar symptoms with virtio_blk (i.e., when guest is booted off a live 
CD and tries to access the disk after migration).

The only difference between SCSI and virtio_blk is that SCSI signals 
errors and aborts, and virtio_blk waits forever and doesn't give a clue.


-- 
Tomasz Chmielewski
http://wpkg.org