Hi, i''m passing dom0_mem=128M to the xen-hypervisor. Then i''m starting two domUs with 435MB each. Now i''m compiling something on my dom0. The dom0 is swapping, and swapping, and swapping. The gcc-process is about 300megabytes. That doesn''t fit into the 128MB. So is there some feature, with a minimum of performenace penalty, that xen manages memory so that memory can be assigned, moved, and so on? I could stop a domU to gain more memory for my dom0. Maybe it''s even possible to tell the domU to free 100MB and assign them to my dom0 temporarly etc. But at the moment, my dom0 has 128MB statically. That''s it. So is there some more flexible way, like i''m imagining? (well, without rebooting?) Thanks, Sven _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi, On Fri, Feb 09, 2007 at 12:55:54AM +0100, Sven Köhler wrote:> So is there some more flexible way, like i''m imagining?You can set the amount of memory per DomU like this: xm mem-set test 256 This sets the amount of memory the DomU "test" can use to 256MB while it''s running. No need to restart the DomU (or Dom0). I don''t know whether there are more advanced (dynamic, automatic) algorithms inplemented right now... Uwe. -- http://www.hermann-uwe.de | http://www.holsham-traders.de http://www.crazy-hacks.org | http://www.unmaintained-free-software.org _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Um, remove dom0_mem=128M or set it higher. The memory allocation is dynamic and grows down as the DomU''s need it. So set it to something like 512mb and let Xen reduce it as it needs to. Also, if you want to compile on the Dom0 then stop the DomU''s so you have the resources available to do the compile. Can you compile the code elsewhere (like in a DomU or on another machine).> -----Original Message----- > From: xen-users-bounces@lists.xensource.com [mailto:xen-users- > bounces@lists.xensource.com] On Behalf Of Sven Köhler > Sent: Thursday, February 08, 2007 3:56 PM > To: xen-users@lists.xensource.com > Subject: [Xen-users] flexible memory management? > > Hi, > > i''m passing dom0_mem=128M to the xen-hypervisor. > Then i''m starting two domUs with 435MB each. > > Now i''m compiling something on my dom0. The dom0 is swapping, and > swapping, and swapping. The gcc-process is about 300megabytes. That > doesn''t fit into the 128MB. > > So is there some feature, with a minimum of performenace penalty, that > xen manages memory so that memory can be assigned, moved, and so on? > > I could stop a domU to gain more memory for my dom0. Maybe it''s even > possible to tell the domU to free 100MB and assign them to my dom0 > temporarly etc. > > But at the moment, my dom0 has 128MB statically. That''s it. > > So is there some more flexible way, like i''m imagining? > (well, without rebooting?) > > > Thanks, > Sven_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> Um, remove dom0_mem=128M or set it higher. The memory allocation is dynamic and grows down as the DomU''s need it. So set it to something like 512mb and let Xen reduce it as it needs to.I am amazed once again! Why do i read dom0_mem=XYZ everywhere? Anyway, I''m testing things right now. Looking forward, to see Xen in action. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> I am amazed once again! > > Why do i read dom0_mem=XYZ everywhere? > > Anyway, I''m testing things right now. Looking forward, to see Xen in > action.Not sure. A post I received to a question I asked which stated " This is an on-going problem confronting Xen users. Quite a bit of blogging and wiki-authoring went into 2.0.7 and early versions of 3. Search engines picked these up quickly and the blog/wiki authors never updated the content." I found that on my 4GB+ machine it helps to reduce some error log messages but it still works fine. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> Um, remove dom0_mem=128M or set it higher. The memory allocation is dynamic and grows down as the DomU''s need it. So set it to something like 512mb and let Xen reduce it as it needs to.So it works! memory is transferred from dom0 to domU on demand. But as i reduce the domU''s size with "xm mem-set", the memory does not flow back to dom0 automatically. I wonder, if that''s possible too. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> So it works! memory is transferred from dom0 to domU on demand. > > But as i reduce the domU''s size with "xm mem-set", the memory does not > flow back to dom0 automatically. > > I wonder, if that''s possible too.That is correct, Dom0 doesn''t seem to grow back. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 2/8/07, Gary W. Smith <gary@primeexalia.com> wrote:> > So it works! memory is transferred from dom0 to domU on demand. > > > > But as i reduce the domU''s size with "xm mem-set", the memory does not > > flow back to dom0 automatically. > > > > I wonder, if that''s possible too. > > That is correct, Dom0 doesn''t seem to grow back.An "old-school" type, like myself, is also reassured somewhat, by allocating only what dom0 would only ever need - net services, compiling, running programs, etc. is isolated to domu''s. Then, in the event dom0 is ever compromised (though very highly unlikely), or even if I accidentally start something there, dom0 can''t take memory away - a DoS prevention, of sorts... jerry -- "Pay no attention to that man behind the curtain!" _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> An "old-school" type, like myself, is also reassured somewhat, by > allocating only what dom0 would only ever need - net services, > compiling, running programs, etc. is isolated to domu''s. Then, in the > event dom0 is ever compromised (though very highly unlikely), or even > if I accidentally start something there, dom0 can''t take memory away - > a DoS prevention, of sorts... >With all honesty, I can''t see why would anyone want to put development tools on the Dom0 in the first place. Actually, why would you run any services (besides maybe SSH) there? I run my Dom0''s as minimal as possible. If there is a need to compile anything I do it on a separate machine or in a DomU configured specifically for development. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 2/8/07, Gary W. Smith <gary@primeexalia.com> wrote:> With all honesty, I can''t see why would anyone want to put development > tools on the Dom0 in the first place. Actually, why would you run any > services (besides maybe SSH) there? > > I run my Dom0''s as minimal as possible. If there is a need to compile > anything I do it on a separate machine or in a DomU configured > specifically for development.Exactly. My new favorite pastime recently has been to parse the package names in the Core group from comps.xml and pass the result to yum --installroot root to create an image. Sigh, oh fun... jerry -- "Pay no attention to that man behind the curtain!" _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 2/8/07, Jerry Amundson <jamundso@gmail.com> wrote:> On 2/8/07, Gary W. Smith <gary@primeexalia.com> wrote: > > I run my Dom0''s as minimal as possible. If there is a need to compile > > anything I do it on a separate machine or in a DomU configured > > specifically for development. > > Exactly. My new favorite pastime recently has been to parse the > package names in the Core group from comps.xml and pass the result to > yum --installroot root to create an image. Sigh, oh fun...Sorry, digressed way off there - domU''s not dom0, but that remind me to test same principle at dom0 install time. Should be able to with a kickstart.cfg, which I''m way overdue to implement anyway... next task for my test server. jerry -- "Pay no attention to that man behind the curtain!" _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Jerry Amundson wrote:> On 2/8/07, Gary W. Smith <gary@primeexalia.com> wrote: >> >> I run my Dom0''s as minimal as possible. If there is a need to compile >> anything I do it on a separate machine or in a DomU configured >> specifically for development. > > Exactly. My new favorite pastime recently has been to parse the > package names in the Core group from comps.xml and pass the result to > yum --installroot root to create an image. Sigh, oh fun... >Why would you need to parse comps.xml? I believe Core still contains stuff like bluez-utils, which you won''t need in a server. If you REALLY want a minimal Redhat-based system I think a simple yum --installroot=/path/to/new/root yum openssh-server would do the trick. If it''s for dom0, then you can add what you need (bridge-utils, vconfig) later Regards, Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 2/8/07, Fajar A. Nugraha <fajar@telkom.net.id> wrote:> Jerry Amundson wrote: > > Exactly. My new favorite pastime recently has been to parse the > > package names in the Core group from comps.xml and pass the result to > > yum --installroot root to create an image. Sigh, oh fun... > > > Why would you need to parse comps.xml? I believe Core still contains > stuff like bluez-utils, which you won''t need in a server. > If you REALLY want a minimal Redhat-based system I think a simple > > yum --installroot=/path/to/new/root yum openssh-server > > would do the trick. If it''s for dom0, then you can add what you need > (bridge-utils, vconfig) later[embarassd grin] Absolutely! Too simple... there I go making things complex for myself. thanks... :-) jerry -- "Pay no attention to that man behind the curtain!" _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On 9 Feb 2007 at 2:12, Sven Köhler wrote:> > Um, remove dom0_mem=128M or set it higher. The memory allocation is dynamic and grows down as the DomU''s need it. So set it to something like 512mb and let Xen reduce it as it needs to. > > I am amazed once again! > > Why do i read dom0_mem=XYZ everywhere?Because Linux tried to avoud unused memory? In my case I was unable to start DomUs after Dom0 was working for a while, even though enough "free" memory should have been present in Dom0 (The machine has 16GB RAM).> > Anyway, I''m testing things right now. Looking forward, to see Xen in action. > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Friday 09 February 2007 04:33, Gary W. Smith wrote:> With all honesty, I can''t see why would anyone want to put development > tools on the Dom0 in the first place. Actually, why would you run any > services (besides maybe SSH) there?gentoo came with it. you have to compile everything (besides binary own-created packages).> I run my Dom0''s as minimal as possible. If there is a need to compile > anything I do it on a separate machine or in a DomU configured > specifically for development.mine too. and i have gentoo. and ssh is the only service (well, i have clvm and children of gfs too, but all "server stuff"). bye d. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
>> I run my Dom0''s as minimal as possible. If there is a need to compile >> anything I do it on a separate machine or in a DomU configured >> specifically for development. > > mine too. > and i have gentoo. > and ssh is the only service (well, i have clvm and children of gfs too, but > all "server stuff").same here, and compiling gcc was not good with 128MB-RAM on dom0 ;-) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users