How to prevent a XenU domain from being saved

Question

Xen (like other) virtual machines allows VMs to be saved and resumed. Xen on Debian Lenny, for instance, is configured to save and resume virtual machines on Dom0 restarts.

Is it possible to have this behavior enabled, but prevent certain VMs from being saved? Reason behind this is that I have some VMs with client data that are using cryptsetup-luks to store the data encrypted and I'd rather not have the encryption key being paged out to the memory save file.

Or is encrypting the storage area of the memory save files the only way around this situation?

Answer 1

You can disable the saving of all domains by editing /etc/default/xendomains and emptying XENDOMAINS_SAVE. From a look at the init script, there doesn't appear to be a simple way of giving a list of domains you'd like to shutdown, while saving others.

I don't like to save domains on shutdown, as it makes dom0 shutdown take significantly longer (prolonging, not shortening, any outage due to dom0 reboot), and quite honestly I don't really see the huge benefit in doing so. A machine that can't be rebooted cleanly is in a severely damaged state (a crash of either the dom0 or domU is going to take you down, regardless, and needs to be a recoverable condition).