svn commit: r216406 - stable/8/sys/amd64/conf

[Julian Elischer]

On 12/13/10 12:07 PM, Robert N. M. Watson wrote:
> On 13 Dec 2010, at 18:28, Ion-Mihai Tetcu <itetcu at FreeBSD.org 
> <mailto:itetcu at FreeBSD.org>> wrote:
>
>> I see. Thanks for the time you took to explain things, I'm very new to
>> XEN.
>> Do we have any docs somewhere (well, except the sources) about our XEN
>> support and various options / optimizations? I only know about
>> AdrianChadd's wiki pags and http://wiki.freebsd.org/FreeBSD/Xen (which
>> are nice, if you happen to know about XEN already and especially if you
>> want to work towards a FreebSD as XEN host).
>> I guess there are more interested people taht want just to run FreeBSD
>> as guest OS (my case).
>
> The current state of our Xen documentation is ... minimalist. Having 
> basically come to it for the first time last week, when we decided 
> we needed to deploy FreeBSD on one of our Xen server pools, it's 
> proven pretty hard-going. I have some more technical problems to 
> resolve but high on my todo list for the next couple of days is 
> documenting what has worked for me on the Wiki (with the intent of 
> migrating that to the Handbook once I've confirmed my instructions 
> are reproducible!). I also want to drop in at least some stub man 
> pages for our PV drivers.
>
> However, more fundamentally, we appear to have some serious 
> functional gaps:
>
> - No ability to use PV drivers under HVM on i386.
> - No ability to use a full PV kernel for amd64 (I don't consider 
> this a problem for my use though -- HVM on amd64 appears to work well).
> - No (obvious) port of Xen guest command line tools to steer 
> ballooning, etc.
> - Likely under-testing in certain PV drivers, such as the balloon 
> driver.
> - A possible issue with VM migration on PV i386 (we saw panics in 
> local testing, but now wonder I it was an unrelated issue relating 
> to different CPU types -- more investigation due).
> - No event mechanism for blkfront to propagate block device 
> expansion up the geom stack, in support of live file system 
> resizing. Right now a destructive orphan/retaste is required.
> - No live file system resizing support in UFS (does work in ZFS).
> - No reference "appliance" images for VM starting points (really 
> requires live file system resizing to be useful). This was a top 
> request o our admin folks.
>
> All this said, and after quite a lot of head-scratching, 
> FreeBSD/amd64 seems to work well on Xen here a Cambridge, both with 
> and without Xen PV drivers compiled in. We need a lot of sanding and 
> polishing but the foundations have been usefully laid. And I would 
> agree that documentation is key.
>
> Robert
you should talk to the people at rootBSD.com
they use Xen to deploy their BSD VPS systems and no doubt have stories 
to tell and suggestions
as to where we could get the best bang for our buck.