Hello,
 I'm trying to test checkpointing, but this stopped me in my tracks:

"Can not suspend VPS: Device or resource busy
SYSV msgqueues are not supported, found 2
Checkpointing failed"

 I tried to look through mailing lists for info on checkpointing, but
all I found is conversations that goes like this
"
 (a) - yeah, openvz is ok, live migration doesn't work though.
 (b) - you're lying, it works for me
 (c) - live migration never worked for me either
 (b) - what are you talking about, I'm migrating things left and right like 
 all the time
"

 wiki says things like "That feature makes possible scenarios such as
upgrading your server without any need to reboot it", and it is all very 
heartwarming, but I can't seem to find list of pre-requisits for
checkpointing to work... any pointers?

 Are there any plans for migrating non-tcp ipc?

Without SYSV dreams of non-vmware live migration quickly fade away, most 
webservers, databases, every non-trivial app that you would like to run
inside VE would make the VE non-migratable, if I understand this correctly

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sorry to reply to myself, but I have just found[1] first moves towards sysv
ipc checkpointing in 2.6.22, so I guess it's wait and see game for me now.

 And to modify my orginal question - are there any additional limits on
checkpointing? Until now I have found that you can't use SYSV IPC and you
can't run stuff via 'vzctl exec' or 'vzctl enter'.

1. http://www.mail-archive.com/devel@openvz.org/msg02797.html
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