Re: [Xen-users] Re: Xen 3.1 released!

Re: [Xen-users] Re: Xen 3.1 released!

[Tomasz Chmielewski]

Petersson, Mats schrieb:

>>>  - 32-on-64 PV guest support (run PAE PV VMs on a 64-bit Xen!); and
>> I checked - indeed it works. It is possible to create a 32 
>> bit PV guest 
>> on a 64-bit Xen.
>>
>> However, migration of such hosts doesn't seem to work: 
>> whenever I try to 
>> migrate a 32-bit PV guest from a 64-bit Xen to a 32-bit Xen (or the 
>> other way around), it fails, and the guest domain is not 
>> reachable anymore.
> 
> No, I seem to remember that this is a known bug - check the Xen Devel
> mailing list archive for the last few weeks, I'm 99% sure there is a
> mention about this particular problem, and I don't think it's
> (completely) fixed in unstable yet either. 

I didn't find any posts about it - at least, not after the 3.1 release 
date (maybe it was discussed earlier).


Also, there's one more feature which doesn't work for me:

  - Preliminary save/restore/migrate support for HVM (e.g. Windows) VMs;


What does "preliminary" mean here? I tried saving/restoring HVM domains, 
but it just doesn't work.

When I try to do /etc/init.d/xendomains stop, it does something for a 
long time, and then, my SSH session is just disconnected.

When I log in again, xend doesn't work anymore:

# xm list
Error: Unable to connect to xend: Connection refused. Is xend running?


When I start xend again, and then start xendomains, there is my domain 
in a weird state:

# xm list
Name                                      ID   Mem VCPUs      State 
Time(s)
Domain-0                                   0   256     2     r-----    134.9
migrating-w2k3-001                         2  1759     1     ---s--     64.4



Similar happens when I try to save the domain manually:

# xm save w2k3-001 /srv/check-2k

And Xen server restarted.

(...)

I inspected the logs, and it was the OOM-killer. Should it ever happen 
when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB 
total), Xen guest 1.7 GB.

-- 
Tomasz Chmielewski
http://wpkg.org

RE: [Xen-users] Re: Xen 3.1 released!

[Petersson, Mats]

 

> -----Original Message-----
> From: Tomasz Chmielewski [mailto:mangoo@wpkg.org] 
> Sent: 25 May 2007 11:54
> To: Petersson, Mats
> Cc: xen-users@lists.xensource.com; xen-devel@lists.xensource.com
> Subject: Re: [Xen-users] Re: Xen 3.1 released!
> 
> Petersson, Mats schrieb:
> 
> >>>  - 32-on-64 PV guest support (run PAE PV VMs on a 64-bit 
> Xen!); and
> >> I checked - indeed it works. It is possible to create a 32 
> >> bit PV guest 
> >> on a 64-bit Xen.
> >>
> >> However, migration of such hosts doesn't seem to work: 
> >> whenever I try to 
> >> migrate a 32-bit PV guest from a 64-bit Xen to a 32-bit 
> Xen (or the 
> >> other way around), it fails, and the guest domain is not 
> >> reachable anymore.
> > 
> > No, I seem to remember that this is a known bug - check the 
> Xen Devel
> > mailing list archive for the last few weeks, I'm 99% sure there is a
> > mention about this particular problem, and I don't think it's
> > (completely) fixed in unstable yet either. 
> 
> I didn't find any posts about it - at least, not after the 
> 3.1 release 
> date (maybe it was discussed earlier).

Yes, it was before the release that someone pointed this out (someone is
most likely either Gerd Hoffman or Jan Beulich). 

> 
> 
> Also, there's one more feature which doesn't work for me:
> 
>   - Preliminary save/restore/migrate support for HVM (e.g. 
> Windows) VMs;
> 
> 
> What does "preliminary" mean here? I tried saving/restoring 
> HVM domains, 
> but it just doesn't work.

It is the first PUBLIC release of the hvm save/restore. 
> 
> When I try to do /etc/init.d/xendomains stop, it does something for a 
> long time, and then, my SSH session is just disconnected.
> 
> When I log in again, xend doesn't work anymore:
> 
> # xm list
> Error: Unable to connect to xend: Connection refused. Is xend running?
> 
> 
> When I start xend again, and then start xendomains, there is 
> my domain 
> in a weird state:
> 
> # xm list
> Name                                      ID   Mem VCPUs      State 
> Time(s)
> Domain-0                                   0   256     2     
> r-----    134.9
> migrating-w2k3-001                         2  1759     1     
> ---s--     64.4
> 
> 
> 
> Similar happens when I try to save the domain manually:
> 
> # xm save w2k3-001 /srv/check-2k
> 
> And Xen server restarted.
> 
> (...)
> 
> I inspected the logs, and it was the OOM-killer. Should it 
> ever happen 
> when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB 
> total), Xen guest 1.7 GB.

Hmm, that's probably something to do with it. Although I'm not sure. 

I've saved 0.5GB domains ona  256MB Dom0 and that works. I'll try to
blow mine up a bit further and see what happens. 

--
Mats
> 
> -- 
> Tomasz Chmielewski
> http://wpkg.org
> 
> 
> 

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Tomasz Chmielewski]

Tomasz Chmielewski schrieb:

> Also, there's one more feature which doesn't work for me:
> 
>  - Preliminary save/restore/migrate support for HVM (e.g. Windows) VMs;
> 
> 
> What does "preliminary" mean here? I tried saving/restoring HVM domains, 
> but it just doesn't work.
> 
> When I try to do /etc/init.d/xendomains stop, it does something for a 
> long time, and then, my SSH session is just disconnected.
> 
> When I log in again, xend doesn't work anymore:
> 
> # xm list
> Error: Unable to connect to xend: Connection refused. Is xend running?
> 
> 
> When I start xend again, and then start xendomains, there is my domain 
> in a weird state:
> 
> # xm list
> Name                                      ID   Mem VCPUs      State Time(s)
> Domain-0                                   0   256     2     r-----    
> 134.9
> migrating-w2k3-001                         2  1759     1     ---s--     
> 64.4
> 
> 
> 
> Similar happens when I try to save the domain manually:
> 
> # xm save w2k3-001 /srv/check-2k
> 
> And Xen server restarted.
> 
> (...)
> 
> I inspected the logs, and it was the OOM-killer. Should it ever happen 
> when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB 
> total), Xen guest 1.7 GB.

It appears that saving of HVM somains needs more memory: in this 
particular case, when I increased memory for dom0, about 350 MB RAM was 
used in total during the domain save.

After that, save/restore was fine.

So I just removed dom0_mem entry from grub; I don't think it's needed.


-- 
Tomasz Chmielewski
http://wpkg.org

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Keir Fraser]

On 25/5/07 12:14, "Tomasz Chmielewski" <mangoo@wpkg.org> wrote:

>> I inspected the logs, and it was the OOM-killer. Should it ever happen
>> when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB
>> total), Xen guest 1.7 GB.
> 
> It appears that saving of HVM somains needs more memory: in this
> particular case, when I increased memory for dom0, about 350 MB RAM was
> used in total during the domain save.

That's kind of surprising, but I guess totally plausible if you don't
configure a swap partition for dom0?

 -- Keir

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Tomasz Chmielewski]

Keir Fraser schrieb:
> 
> 
> On 25/5/07 12:14, "Tomasz Chmielewski" <mangoo@wpkg.org> wrote:
> 
>>> I inspected the logs, and it was the OOM-killer. Should it ever happen
>>> when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB
>>> total), Xen guest 1.7 GB.
>> It appears that saving of HVM somains needs more memory: in this
>> particular case, when I increased memory for dom0, about 350 MB RAM was
>> used in total during the domain save.
> 
> That's kind of surprising, but I guess totally plausible if you don't
> configure a swap partition for dom0?

No - dom0 has a 2 GB swap partition.


-- 
Tomasz Chmielewski
http://wpkg.org

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Keir Fraser]

On 25/5/07 13:57, "Tomasz Chmielewski" <mangoo@wpkg.org> wrote:

>>>> I inspected the logs, and it was the OOM-killer. Should it ever happen
>>>> when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB
>>>> total), Xen guest 1.7 GB.
>>> It appears that saving of HVM somains needs more memory: in this
>>> particular case, when I increased memory for dom0, about 350 MB RAM was
>>> used in total during the domain save.
>> 
>> That's kind of surprising, but I guess totally plausible if you don't
>> configure a swap partition for dom0?
> 
> No - dom0 has a 2 GB swap partition.

Hmmm... That's not so explicable. Obviously something in save/restore is
causing unpageable allocations to happen. Could be pagetables for mappings
of HVM guest memory, or something like that. Needs investigating further, I
think.

 -- Keir

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Tomasz Chmielewski]

Keir Fraser schrieb:
> 
> 
> On 25/5/07 13:57, "Tomasz Chmielewski" <mangoo@wpkg.org> wrote:
> 
>>>>> I inspected the logs, and it was the OOM-killer. Should it ever happen
>>>>> when saving a guest domain? Xen host has 256 MB RAM for dom0 (3 GB
>>>>> total), Xen guest 1.7 GB.
>>>> It appears that saving of HVM somains needs more memory: in this
>>>> particular case, when I increased memory for dom0, about 350 MB RAM was
>>>> used in total during the domain save.
>>> That's kind of surprising, but I guess totally plausible if you don't
>>> configure a swap partition for dom0?
>> No - dom0 has a 2 GB swap partition.
> 
> Hmmm... That's not so explicable. Obviously something in save/restore is
> causing unpageable allocations to happen. Could be pagetables for mappings
> of HVM guest memory, or something like that. Needs investigating further, I
> think.

Could be.

Now that I repeated the save/restore a couple of times, total RAM usage 
for dom0 jumps to ~700 MB sometimes during domain save (dom0 has now 
about 2.3 GB RAM, domU has 1.7 GB RAM; 4 GB RAM installed now in the 
machine).


-- 
Tomasz Chmielewski
http://wpkg.org

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Keir Fraser]

On 25/5/07 14:20, "Tomasz Chmielewski" <mangoo@wpkg.org> wrote:

>> Hmmm... That's not so explicable. Obviously something in save/restore is
>> causing unpageable allocations to happen. Could be pagetables for mappings
>> of HVM guest memory, or something like that. Needs investigating further, I
>> think.
> 
> Could be.
> 
> Now that I repeated the save/restore a couple of times, total RAM usage
> for dom0 jumps to ~700 MB sometimes during domain save (dom0 has now
> about 2.3 GB RAM, domU has 1.7 GB RAM; 4 GB RAM installed now in the
> machine).

The only thing I would expect could so dramatically inflate dom0's memory
usage would be caching of disc blocks from the saved image file. But we
added explicit cache flushing to both domain-save and domain-restore before
releasing 3.1. The flushes are only advisory though, so perhaps they are
getting ignored for some reason.

 -- Keir

Re: Re: [Xen-users] Re: Xen 3.1 released!

[Tomasz Chmielewski]

Keir Fraser schrieb:
> On 25/5/07 14:20, "Tomasz Chmielewski" <mangoo@wpkg.org> wrote:
> 
>>> Hmmm... That's not so explicable. Obviously something in save/restore is
>>> causing unpageable allocations to happen. Could be pagetables for mappings
>>> of HVM guest memory, or something like that. Needs investigating further, I
>>> think.
>> Could be.
>>
>> Now that I repeated the save/restore a couple of times, total RAM usage
>> for dom0 jumps to ~700 MB sometimes during domain save (dom0 has now
>> about 2.3 GB RAM, domU has 1.7 GB RAM; 4 GB RAM installed now in the
>> machine).
> 
> The only thing I would expect could so dramatically inflate dom0's memory
> usage would be caching of disc blocks from the saved image file. But we
> added explicit cache flushing to both domain-save and domain-restore before
> releasing 3.1. The flushes are only advisory though, so perhaps they are
> getting ignored for some reason.

For your notice, I just saw 1.3 GB RAM usage when doing a 1.7 GB HVM 
domain save :)


-- 
Tomasz Chmielewski
http://wpkg.org

RE: [Xen-users] Re: Xen 3.1 released!

[Cui, Dexuan]

You can step into the directory docs/, that is in the top directory of Xen source code, then "make" for your docs in various formats (i.e., pdf, html, ps,tex,...).
You should get be a user manual and development manual.

-- Dexuan

-----Original Message-----
From: xen-devel-bounces@lists.xensource.com [mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of Yuzhong Sun
Sent: 2007年5月22日 12:07
To: 'Tony Breeds'; 'Keir Fraser'
Cc: 'xen-devel'; xen-users@lists.xensource.com
Subject: 答复: [Xen-users] Re: [Xen-devel] Xen 3.1 released!

Xen 3.1 announces some new features. Where do I obtain its manual for Xen 3.
1? I visited Xen WIKI including the general version of Xem 3.0 manual.

-Yuzhong

-----邮件原件-----
发件人: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] 代表 Tony Breeds
发送时间: 2007年5月21日 9:27
收件人: Keir Fraser
抄送: xen-devel; xen-users@lists.xensource.com
主题: [Xen-users] Re: [Xen-devel] Xen 3.1 released!

On Fri, May 18, 2007 at 05:11:17PM +0100, Keir Fraser wrote:

> We're pleased to announce the official release of Xen 3.1!

Congratulations!
(I removed xen-announce from the CC as I figured that's not really the
place for this email [and it's probably moderated :)] )

<snip>
 
> You can get the source using mercurial from:
>   http://xenbits.xensource.com/xen-3.1-testing.hg
> 
> Source and binary tarballs, and RPMs, are available from:
>   http://www.xensource.com/download/index_oss.html

I realise that releases are relatively rare, and this one is somewhat
special (with the version numbering change), so the process has some
rough edges.

I'd like to make the following observations.
 * Many of the logos on the Xensource site still include the "3.0"
   branding eg.
   http://www.xensource.com/images/products/xen_30_r_logo.gif
 * It's be nice if there was a download tarball link from:
   http://www.xensource.com/download/index_oss.html
   Sure there iare "Mercurial Repository" and "Source Browser" links but
   they're not really the same.  Is it really a requirement to use
   Mercurial to get the code?
 * The Mercurial Repository doesn't contain a tag "3.1.0" or
   "3.1.0-final", and the Mercurial Repository is still called
   3.1-testing.  This makes it a little non-obvious and also if you're
   pointing people at a download page for the latest and greatest it
   doesn't create a sense of confidence :)

It'd be nice to add this little bit of polish if possible.

Yours Tony

  linux.conf.au        http://linux.conf.au/ || http://lca2008.linux.org.au/
  Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!


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