Ian Brown
2006-Feb-08 15:34 UTC
[Xen-users] Is there a limit on the number of guest domains ?
Hello, Is there a limit on on the number of guest domains dom0 can create ? Or is it dependant on the abilities of the machines which runs dom0 and the memory parameter with which we create the domain? IB _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ralph Passgang
2006-Feb-08 16:32 UTC
Re: [Xen-users] Is there a limit on the number of guest domains ?
Am Mittwoch, 8. Februar 2006 16:34 schrieb Ian Brown:> Hello, > Is there a limit on on the number of guest domains dom0 can create ? > Or is it dependant on the abilities of the machines which runs dom0 > and the memory parameter with which we create the domain? > IBit''s limited by the physical resources that you have available, there should be no other hardcoded limit (or at least only a very high and more theoretical limit). If you have assigned all of your memory to guests, then you will not be able to create another new guest. Same if you run out of harddisk. CPU shouldn''t be a problem at all, even it doesn''t make sense to have hundreds of guests running on just one physical cpu. My "biggest" setup was a dual xeon server with 4gb ram and 24 domUs running (without any problems). If you have more ram available then even 50 domUs should be possible on such a server (if you have more or less just tiny domU''s at least). --Ralph _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Puthiyaparambil, Aravindh
2006-Feb-08 16:33 UTC
RE: [Xen-users] Is there a limit on the number of guest domains ?
We did a few scalability tests on x86_64 Xen and found that the upper limit on DomUs is 87. This is of course on a system that has enough system memory to support that many DomUs as Xen does not over-commit memory. In our tests each DomU had 64MB of RAM. Aravindh Unisys, Tredyffrin PA E-Mail: aravindh.puthiyaparambil@unisys.com> -----Original Message----- > From: Ian Brown [mailto:ianbrn@gmail.com] > Sent: Wednesday, February 08, 2006 10:34 AM > To: xen-users@lists.xensource.com > Subject: [Xen-users] Is there a limit on the number of guest domains ? > > Hello, > Is there a limit on on the number of guest domains dom0 can create ? > Or is it dependant on the abilities of the machines which runs dom0 > and the memory parameter with which we create the domain? > IB >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ralph Passgang
2006-Feb-08 17:02 UTC
Re: [Xen-users] Is there a limit on the number of guest domains ?
Am Mittwoch, 8. Februar 2006 17:33 schrieb Puthiyaparambil, Aravindh:> We did a few scalability tests on x86_64 Xen and found that the upper > limit on DomUs is 87. This is of course on a system that has enough > system memory to support that many DomUs as Xen does not over-commit > memory. In our tests each DomU had 64MB of RAM.interessting... but what happend after domU no. 87? what message/error do you saw then? how much memory had your x86_64 testsystem? on wich xen version have you made these tests? i would like to understand why there is such a limit... --Ralph> > Aravindh > Unisys, Tredyffrin PA > E-Mail: aravindh.puthiyaparambil@unisys.com > > > -----Original Message----- > > From: Ian Brown [mailto:ianbrn@gmail.com] > > Sent: Wednesday, February 08, 2006 10:34 AM > > To: xen-users@lists.xensource.com > > Subject: [Xen-users] Is there a limit on the number of guest domains ? > > > > Hello, > > Is there a limit on on the number of guest domains dom0 can create ? > > Or is it dependant on the abilities of the machines which runs dom0 > > and the memory parameter with which we create the domain? > > IB > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Puthiyaparambil, Aravindh
2006-Feb-08 17:12 UTC
RE: [Xen-users] Is there a limit on the number of guest domains ?
> Am Mittwoch, 8. Februar 2006 17:33 schrieb Puthiyaparambil, Aravindh: > > We did a few scalability tests on x86_64 Xen and found that theupper> > limit on DomUs is 87. This is of course on a system that has enough > > system memory to support that many DomUs as Xen does not over-commit > > memory. In our tests each DomU had 64MB of RAM. > > interessting... but what happend after domU no. 87? what message/errordo> you > saw then? how much memory had your x86_64 testsystem? on wich xenversion> have you made these tests?The test was done on a 32x ES7000 with 8GB memory. We started 87 SLES9 "minimum" DomUs with 64MB of RAM. Xentop reported 6 GB used, but we got an "out of memory error" when we tried to start the 88th. This happened even when more memory was given to Dom0.> > i would like to understand why there is such a limit... >It has something to do with the way heap allocation is done in Xen. If the heap allocation is made dynamic then this limit would go away. But from what Kier told me, it is a big change and we should hold off on this for the moment. Aravindh _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users