Re: Does "xm save" and "xm migrate" work with NetBSD 5.0 domU?

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

Martti Kuparinen wrote:
> Hi,
>
> I have two 64-bit CentOS 5.2 dom0s and two NetBSD 5.0_RC2 domUs (32-bit 
> and 64-bit -- both on iSCSI target). I can start/stop both domUs without 
> any problems but I can't save or migrate them.
>
> Since I'm no expert in this area, do "xm save" and "xm migrate" commands 
> need support in the domU?

Yes, in the pmap(9) and the xen drivers (xencons, xbd, xennet, ...)

> Does NetBSD 5.0 have it?

Not for the domU.

Support in dom0 was fixed in 5.0 (== means that you should be able to 
save/restore/migrate Linux or Solaris domUs from a NetBSD-5 dom0).

> Here's my question on the xen list:
>
> http://lists.xensource.com/archives/html/xen-users/2009-03/msg00137.html

save/restore/migrate of the domU will be included in NetBSD-6. Not 
likely to appear in 5.x, except if we accept major overhaul in the xen 
driver parts.

FYI, the branch for this work is jym-xensuspend, it will be updated in 
the next few days.

[from your message on xen-users]
> What is that "ERROR Internal error: read extended-info signature failed" message? 

xentools tries to read information from the p2m tables, which are arrays 
containing all PFN to MFN translations (this is required by the way x86 
architecture works - PFN are pseudo physical frame numbers, and MFN are 
the real machine ones - those that are used by MMUs and TLBs).

In your case, one entry was invalid during the save (see the error about 
p2m_frame_list[0] for example), which ended up badly when writing the 
core image. Restore failed consequently; migrate is a special case where 
save and restore operations are done in one fast succession.

Cheers,

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost