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Re: [Xen-devel] Re: XenParavirtOps wiki page updates

Ferenc Wagner wrote:
Thanks for collecting this very useful bunch of information!
Here is what I still miss:

 * Features in 2.6.26:
     Balloon (contraction only)

   It isn't clear whether this contraction is reversible or not.

It is, but only up to the original size.

 * If the domain crashes very early, before any output appears on the
   console, then booting with: should provide some useful information.

   Booting with what?


 * How to achieve time sync between the dom0 and the domUs?  Lots of
   people seem to have problem with domU clock drift, me included.
   Ntp doesn't work in domU, and apparently no clocksource guarantees
   such synchronization.

Why doesn't ntp work?  As far as I know it should.

The 2.6.18-xen kernels have a mechanism to try and sync the domains to the hypervisor's time, but it doesn't fit well into the current kernel's timekeeping. I think either ntp or a lightweight daemon should be able to do this from usermode. (I was thinking of adding some /sys files to publish the hypervisor's current time, which a daemon could use to warp the domain's time to match.)

 * I couldn't find it documented anywhere that SysRq is available via
   Ctrl+O on the domU and more importantly on the dom0 serial console.

 * The idle count doubling I still experience happens with pvops
   guests only (http://lkml.org/lkml/2008/9/18/276).

That is pretty strange.

Otherwise, Debian's pvops guest kernel works very good for me, already
in production.

Good to hear.  32 or 64 bit?


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