Rachid Abdoun
2006-Jun-16 09:44 UTC
[Xen-users] How can we increase de maximum memory for a domU
Hi, On a virtual network project, we are using xen. We haven''t any information in xen documentation on the parameter MAXMEM. Are the ram of domU static or can it increase dynamicaly? Could someone explain how does it work? Thank you greets - Rachid _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Jonathan Ervine
2006-Jun-18 20:04 UTC
Re: [Xen-users] How can we increase de maximum memory for a domU
On Friday 16 June 2006 10:44, Rachid Abdoun wrote:> Hi, > > On a virtual network project, we are using xen. We haven''t any > information in xen documentation on the parameter MAXMEM. Are the ram > of domU static or can it increase dynamicaly? Could someone explain > how does it work? Thank you >You can change the amount of memory in a XEN DomU, however it seems the DomU does not recognise any memory assigned to it above the amount specified in the DomU config file. However I can reduce it dynamically and increase it back up to that maximum value. For example, I can specify 1024MB as the initial amount, then reduce the amount of memory to 64MB, then increase back 768MB, however I cannot go to 1536MB as that is greater than my starting 1024MB. The command for adjusting domain memory is xm mem-set <domID> <mem> Particularly for hardware assisted fully virtualised operating systems stability seems to improve by reducing Dom0 memory as much as possible. Hope this helps, Jon _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Rachid Abdoun
2006-Jun-21 10:51 UTC
Re: [Xen-users] How can we increase de maximum memory for a domU
But when you execute xentop (xen 3.0.2) you can see a column named "MAXMEM" and this value is greate than the value fixed in the conf file... What does mean this option (if there is enough memory and a domU need more memory, that''s mean the domU can use more memory that the memory assigned by the conf file??? ) ? How can we adjuste it? Le 18 juin 06 à 22:04, Jonathan Ervine a écrit :> On Friday 16 June 2006 10:44, Rachid Abdoun wrote: >> Hi, >> >> On a virtual network project, we are using xen. We haven''t any >> information in xen documentation on the parameter MAXMEM. Are the ram >> of domU static or can it increase dynamicaly? Could someone explain >> how does it work? Thank you >> > You can change the amount of memory in a XEN DomU, however it seems > the DomU > does not recognise any memory assigned to it above the amount > specified in > the DomU config file. However I can reduce it dynamically and > increase it > back up to that maximum value. For example, I can specify 1024MB as > the > initial amount, then reduce the amount of memory to 64MB, then > increase back > 768MB, however I cannot go to 1536MB as that is greater than my > starting > 1024MB. > > The command for adjusting domain memory is xm mem-set <domID> <mem> > > Particularly for hardware assisted fully virtualised operating systems > stability seems to improve by reducing Dom0 memory as much as > possible. > > Hope this helps, > Jon > > _______________________________________________ > 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
Jonathan Ervine
2006-Jun-22 12:49 UTC
Re: [Xen-users] How can we increase de maximum memory for a domU
On Wednesday 21 June 2006 11:51, Rachid Abdoun wrote:> But when you execute xentop (xen 3.0.2) you can see a column named > "MAXMEM" and this value is greate than the value fixed in the conf > file... > > What does mean this option (if there is enough memory and a domU need > more memory, that''s mean the domU can use more memory that the memory > assigned by the conf file??? ) ? How can we adjuste it? >You can certainly assign more memory dynamically to a running Xen DomU, however from my tests so far the OS running in the DomU hasn''t recognised the additional memory available to it. So far it looks like the maximum memory recognised by the DomU is the amount assigned in the conf file. Jon _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Timo Benk
2006-Jun-22 13:25 UTC
Re: [Xen-users] How can we increase de maximum memory for a domU
On Thu, 22 Jun 2006 13:49:23 +0100, Jonathan Ervine <jervine@novell.com> wrote:> On Wednesday 21 June 2006 11:51, Rachid Abdoun wrote: >> But when you execute xentop (xen 3.0.2) you can see a column named >> "MAXMEM" and this value is greate than the value fixed in the conf >> file... >> >> What does mean this option (if there is enough memory and a domU need >> more memory, that''s mean the domU can use more memory that the memory >> assigned by the conf file??? ) ? How can we adjuste it? >> > You can certainly assign more memory dynamically to a running Xen DomU, > however from my tests so far the OS running in the DomU hasn''t recognised > the > additional memory available to it. So far it looks like the maximum memory > recognised by the DomU is the amount assigned in the conf file.I am quite sure that this is wrong. Looking at /proc/xen/balloon, which is a xen specific and not os specific thingy, you can see that a hard limit is reached. The Hard Limit appears when you try to increase the memory amount above the value set in the config file. And the hard limit is just a little below this initally set value. Greetings, -timo -- Timo Benk - Jabber ID: fry@jabber.org - ICQ ID: #241877854 PGP Public Key: http://m28s01.vlinux.de/timo_benk_gpg_key.asc _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users