It seems that Xen VMs are subject to file system corruption under certain conditions. I find that often when I reboot or shutdown a VM the filesystem is corrupted after that and the VM no longer usable. The xm create then fails with some Python errors and an eventual
Runtime Error: unable to read filesystem No handlers could be found for logger "xend". Error: boot loader didn't return any data.
and I have to throw it away as there doesn't seem a way to fix that (or is there?). I use files for storing the VMs. There is enough space on the drive. The problem seems to happen when I reboot the machine from within itself, not each time, but almost each time. When I shut it down with CTRL+ALT+DEL or with the Shutdown button it doesn't seem to happen. I also find that sometimes a good VM will start up and crash early with a kernel panic, but start up just fine when I try a second or third time. Most often this happened after a new installation on the first reboot.
Anyone else seen this or known how to fix that?
Kai
On 10/12/07, Kai Schaetzl maillists@conactive.com wrote:
It seems that Xen VMs are subject to file system corruption under certain conditions. I find that often when I reboot or shutdown a VM the filesystem is corrupted after that and the VM no longer usable. The xm create then fails with some Python errors and an eventual
Runtime Error: unable to read filesystem No handlers could be found for logger "xend". Error: boot loader didn't return any data.
and I have to throw it away as there doesn't seem a way to fix that (or is there?). I use files for storing the VMs. There is enough space on the drive. The problem seems to happen when I reboot the machine from within itself, not each time, but almost each time. When I shut it down with CTRL+ALT+DEL or with the Shutdown button it doesn't seem to happen. I also find that sometimes a good VM will start up and crash early with a kernel panic, but start up just fine when I try a second or third time. Most often this happened after a new installation on the first reboot.
Anyone else seen this or known how to fix that?
I have not seen this... and my setup seems similar to yours. I have been building and rebuilding xen boxes, rebooting and running them quite a bit. I would first suspect dodgy hardware.
Stephen John Smoogen wrote on Fri, 12 Oct 2007 13:37:51 -0600:
I have not seen this... and my setup seems similar to yours. I have been building and rebuilding xen boxes, rebooting and running them quite a bit. I would first suspect dodgy hardware.
Definitely not. It's only the VMs that have a problem, not the main system and when it happens the whole VM filesystem file is just gone (well, it is there, but only 24 KB or so). It seems that Xen sometimes doesn't write the filesystem file when the system shuts itself down or reboots. Or it doesn't really create the filesystem at installation time, so there is nothing to reboot to. When you use files for storing the VM, do you *un*check the "Allocate entire virtual disk now" option? I do as I'm currently setting up quite a few for testing and rolling out all the space would restrict me in the number of test files I can have. But I always make sure that there is enough disk space in case the VM needs the full capacity. I think sparse files are used for that, maybe there lies the problem? Obviously, the possibility I can loose a complete VM doesn't make it very reliable :-( Apart from this problem the VMs work for me just nicely.
Kai
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Kai Schaetzl -
Stephen John Smoogen