Hello, System has the following Config. 2x E5620 98GB Memory What would you suggest the best value for dom0_mem= would be for this type of system? Set it to 4GB of memory now on each one. Just before the server would freeze and the IPMI returned a back screen, so not completely sure. _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 9 May 2012 10:43, CobraHost <cobrahost@hotmail.co.uk> wrote:> Hello, > > System has the following Config. > > 2x E5620 > 98GB Memory > > What would you suggest the best value for dom0_mem= would be for this type > of system? > Set it to 4GB of memory now on each one.Hi! I think it should be a good value, considering you have 98GB of RAM, but let me make you a question please: once you''ve booted the system, do you see all the 98GB available if you do ''cat /proc/meminfo'' or ''free''? Regards, -- Flavio
On 9 May 2012 10:54, CobraHost <cobrahost@hotmail.co.uk> wrote:> cat /proc/meminfo > MemTotal: 4194304 kBThis doesn't seem to be the total amount of RAM you have on your system, which is actually 98GB. Please remember to Cc the list. -- Flavio _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 9 May 2012 10:58, CobraHost <cobrahost@hotmail.co.uk> wrote:> Hello, > > Appended the grub line with domo_mem=4096mYes, I did understand. I was talking about this issue: http://lists.xen.org/archives/html/xen-users/2011-12/msg00069.html -- Flavio
On 9 May 2012 11:08, CobraHost <cobrahost@hotmail.co.uk> wrote:> Hello,Could you Cc the list please?> > when you modify the grub.conf with dom0_mem=4096m it won''t show the total > memory amount.Yes, I know but if I put dom0_mem=1024M, I see the dom0 has 1GB of RAM, and free (or cat /proc/meminfo) gives me only 300MB of free RAM and it should give me 3GB of free RAM since I have a total amount of 4GB on my system. For this reason I was asking this. -- Flavio
On 9 May 2012 11:47, CobraHost <cobrahost@hotmail.co.uk> wrote:> Hello, > > I''m guessing this has something to do with the kernel we are using since it > is majorly outdated. and we are running RHEL 5.8Yes, and as far as I know this problem is still not fixed. No more news from the dev team. PS: I don''t know if you reply to the list including the list address in the Bcc field, but I would ask you to always include the list address in the Cc field, because I see every reply from you only directed to me. Thank you. -- Flavio
On 09/05/12 10:43, Flavio wrote:> On 9 May 2012 11:08, CobraHost<cobrahost@hotmail.co.uk> wrote: >> Hello, > Could you Cc the list please? > >> >> when you modify the grub.conf with dom0_mem=4096m it won''t show the total >> memory amount. > Yes, I know but if I put dom0_mem=1024M, I see the dom0 has 1GB of RAM, and > free (or cat /proc/meminfo) gives me only 300MB of free RAM and it > should give me > 3GB of free RAM since I have a total amount of 4GB on my system. >Surely, since you''ve given dom0 only 1024M, it''s correct for /proc/meminfo to return 1GB. What does ''xm info'' say? That should tell you how much memory Xen thinks it has to work with. Matthew -- Scanned by iCritical. _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 9 May 2012 13:32, Matthew Wild <Matthew.Wild@stfc.ac.uk> wrote:> Surely, since you''ve given dom0 only 1024M, it''s correct for /proc/meminfo > to return 1GB.No, it doesn''t return 1GB. It returns about 300MegaBytes and such value may vary. -- Flavio
On 09/05/12 12:38, Flavio wrote:> On 9 May 2012 13:32, Matthew Wild<Matthew.Wild@stfc.ac.uk> wrote: >> Surely, since you''ve given dom0 only 1024M, it''s correct for /proc/meminfo >> to return 1GB. > No, it doesn''t return 1GB. It returns about 300MegaBytes and such value > may vary. >MemTotal: or MemFree:? What does ''xm info'' say? Matthew -- Scanned by iCritical. _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 9 May 2012 13:49, Matthew Wild <Matthew.Wild@stfc.ac.uk> wrote:> MemTotal: or MemFree:?I''ve set dom0_mem=1024M If I try to start XEN on my laptop, which has 8GB of RAM, I get: MemTotal: 819316 kB <---- which is approximately 0.78GByte !!! MemFree: 662416 kB <------ o.0 ??? ==================================same as above # free total used free Mem: 819316 157260 662056 ================================== And this is OK: # xl list Name ID Mem Domain-0 0 1023 ==================================> > > What does ''xm info'' say?# xl info total_memory : 8107 free_memory : 6968 As you can see, my 8GB of RAM have disappeared. What can you say about that? -- Flavio
On Wed, 2012-05-09 at 17:52 +0200, Flavio wrote:> > What does ''xm info'' say? > # xl info > total_memory : 8107 > free_memory : 6968 >So, 8GB of RAM is what Xen knows, ~7 of them being free... What''s the problem?> As you can see, my 8GB of RAM have disappeared. > What can you say about that? >Uh? :-O Ok, this might be a bit too technical, but perhaps still of help: http://blog.xen.org/index.php/2012/04/30/do%EF%BB%BFm0-memory-where-it-has-not-gone/ I''m also sure this has been mentioned in this or another thread related to this "issue": http://wiki.xen.org/wiki/Xen_Best_Practices http://wiki.xen.org/wiki/Xen_Best_Practices#Why_should_I_dedicate_fixed_amount_of_memory_for_Xen_dom0.3F Also trying to quickly summarize what''s happening, no, your memory _has_not_ disappeared. Actually, it is right there for your VMs to use it (and xl invocation above shows right that). With dom0_mem=1G you told Xen that one of your VM (the one that it will automatically call ''Domain0'' and that it will automatically create on boot) will use 1G of your 8G of RAM. If you now try to create another VM (say ''VM_1'') with 2G of RAM, it will just do that, and you''ll have 1G +2G=3G out of 8G of your RAM dedicated to these two VMs, while the other 5G are still free. Have you tried that? If you do, try running `xl info'' on Dom0 again after that. Try also SSH-ing in ''VM_1'' and asking (e.g., via `free -m'') how many total and free memory it has. As one should expect, it will say it has 2GB of RAM in total... Does this make sense? So, again, the reason why you''re not seeing 7GB of RAM in Dom0 is because they''re not there! Dom0 is a virtual machine to which you''ve given 1GB of RAM via the cmdline... Having only 1GB of RAM is just doing right what you asked for! I can understand that it might look a bit tricky, but what you seem to be missing here is you should consider Dom0 pretty much like any other VM that Xen is managing as the hypervisor. Hope of being of some help. Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 10 May 2012 12:38, Dario Faggioli <raistlin@linux.it> wrote:> On Wed, 2012-05-09 at 17:52 +0200, Flavio wrote: >> > What does 'xm info' say? >> # xl info >> total_memory : 8107 >> free_memory : 6968 >> > So, 8GB of RAM is what Xen knows, ~7 of them being free... What's the > problem?Yes, but as far as I can see, even if xl info gives me such values, the real amount of free RAM is very less than it declares. I've reported also the free and the cat /proc/meminfo output on the purpose and what I can see, practically, is that I cannot run Chromium, or other "big" applications because of this lack of free RAM. This is an issue that has been confirmed many months ago.> >> As you can see, my 8GB of RAM have disappeared. >> What can you say about that? >> > Uh? :-OIf you look at xl info, you are right when you do this face, but the practical issues that I am facing with, confirm that there is something not working properly, when the hypervisor is running.> > Ok, this might be a bit too technical, but perhaps still of help: > http://blog.xen.org/index.php/2012/04/30/do%EF%BB%BFm0-memory-where-it-has-not-gone/Thanks, but this didn't help me to fix the problem.> > I'm also sure this has been mentioned in this or another thread related > to this "issue": > http://wiki.xen.org/wiki/Xen_Best_Practices > http://wiki.xen.org/wiki/Xen_Best_Practices#Why_should_I_dedicate_fixed_amount_of_memory_for_Xen_dom0.3FAlready seen that a lot of times.> > Also trying to quickly summarize what's happening, no, your memory > _has_not_ disappeared. Actually, it is right there for your VMs to use > it (and xl invocation above shows right that).OK, I was just only wandering why I was experiencing system slow downs, as reported above. I don't know what would happen if several VMs would be running at the same time.> > With dom0_mem=1G you told Xen that one of your VM (the one that it will > automatically call 'Domain0' and that it will automatically create on > boot) will use 1G of your 8G of RAM. If you now try to create another VM > (say 'VM_1') with 2G of RAM, it will just do that, and you'll have 1G > +2G=3G out of 8G of your RAM dedicated to these two VMs, while the other > 5G are still free.Great. This is perfectly clear now. But you would certainly understand my perplexity when I see only 662416 kB of free memory in cat /proc/meminfo. That is smaller than 5GB you mentioned above.> > Have you tried that? If you do, try running `xl info' on Dom0 again > after that. Try also SSH-ing in 'VM_1' and asking (e.g., via `free -m') > how many total and free memory it has. As one should expect, it will say > it has 2GB of RAM in total... Does this make sense?Sure it has. I don't have anything to say about that actually. If my domUs have the right amount of RAM I decided to assign to each one, this is certainly perfect, but I was worried about what is happening on the dom0, not allowing me to see all the free RAM I should see.> > So, again, the reason why you're not seeing 7GB of RAM in Dom0 is > because they're not there! Dom0 is a virtual machine to which you've > given 1GB of RAM via the cmdline... Having only 1GB of RAM is just doing > right what you asked for!Uhm, OK. So all my doubts come from the fact that, when I was using xen-sources (and not the vanilla (gentoo) sources), I've always seen all the free RAM correctly. But if you say this, I can be more pacific. ;-)> > I can understand that it might look a bit tricky, but what you seem to > be missing here is you should consider Dom0 pretty much like any other > VM that Xen is managing as the hypervisor.Yes, this is clear to me. Thank you for remarking this point anyway.> > Hope of being of some help.For sure yes! I appreciate your interest. Thank you so much. Best Regards, Flavio _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Thu, 2012-05-10 at 14:20 +0200, Flavio wrote:> On 10 May 2012 12:38, Dario Faggioli <raistlin@linux.it> wrote: > > On Wed, 2012-05-09 at 17:52 +0200, Flavio wrote: > >> > What does ''xm info'' say? > >> # xl info > >> total_memory : 8107 > >> free_memory : 6968 > >> > > So, 8GB of RAM is what Xen knows, ~7 of them being free... What''s the > > problem? > Yes, but as far as I can see, even if xl info gives me such values, > the real amount > of free RAM is very less than it declares. I''ve reported also the free and the > cat /proc/meminfo output on the purpose and what I can see, practically, is that > I cannot run Chromium, or other "big" applications because of this lack of free > RAM. This is an issue that has been confirmed many months ago. >Just to be sure we got each other properly, that is again fine, as /proc/meminfo or `free'' in Dom0 reports the amount of free memory in Dom0, which is a VM to which you''ve given 1GB of RAM. Then, if your Dom0 has issues (slowdowns, OOM killings, etc.) with that amount of RAM you either should put more memory on dom0_mem= or avoid putting the dom0_mem option at all. Of course, the wiki links tells you shouldn''t get rid of that cmdline option but, hey, one has to be free to do what he likes on his machines! :-P It''s not hard to imagine that 1GB (unfortunately) is far less what a modern Desktop needs to run properly. And about the latter point, if you install the xen packages on Fedora, it does not give you any dom0_mem option by default, so...> Uhm, OK. So all my doubts come from the fact that, when I was using > xen-sources (and not the vanilla (gentoo) sources), I''ve always seen all the > free RAM correctly. But if you say this, I can be more pacific. ;-) >That could well be true. I''m hacking on Xen from a very short while, so I''m not going to claim it has always been like it is now! :-D> > Hope of being of some help. > For sure yes! I appreciate your interest. >Glad to hear that. :-) Regards, Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 10 May 2012 19:26, Dario Faggioli <raistlin@linux.it> wrote:> Just to be sure we got each other properly, that is again fine, > as /proc/meminfo or `free'' in Dom0 reports the amount of free memory in > Dom0, which is a VM to which you''ve given 1GB of RAM. > > Then, if your Dom0 has issues (slowdowns, OOM killings, etc.) with that > amount of RAM you either should put more memory on dom0_mem= or avoid > putting the dom0_mem option at all.Well, with regard to this point, I''ve done many different tests during the last period actually, just to see how it behaves. I stated that if I give too much RAM to dom0, the system is unusable (~3-4GB, or ~7-8 for the laptop). If I avoid to set such parameter, the amount of free RAM is random! One time I can get 3 or 4 GB free (for my desktop PC with 4GB of RAM) or 300MB free, or some other random value.> Of course, the wiki links tells you > shouldn''t get rid of that cmdline option but, hey, one has to be free to > do what he likes on his machines! :-PLOL, of course! :-) Best regards, Flavio
On Wed, 2012-05-09 at 17:52 +0200, Flavio wrote:> > What does ''xm info'' say? > # xl info > total_memory : 8107 > free_memory : 6968 >So, 8GB of RAM is what Xen knows, ~7 of them being free... What''s the problem?> As you can see, my 8GB of RAM have disappeared. > What can you say about that? >Uh? :-O Ok, this might be a bit too technical, but perhaps still of help: http://blog.xen.org/index.php/2012/04/30/do%EF%BB%BFm0-memory-where-it-has-not-gone/ I''m also sure this has been mentioned in this or another thread related to this "issue": http://wiki.xen.org/wiki/Xen_Best_Practices http://wiki.xen.org/wiki/Xen_Best_Practices#Why_should_I_dedicate_fixed_amount_of_memory_for_Xen_dom0.3F Also trying to quickly summarize what''s happening, no, your memory _has_not_ disappeared. Actually, it is right there for your VMs to use it (and xl invocation above shows right that). With dom0_mem=1G you told Xen that one of your VM (the one that it will automatically call ''Domain0'' and that it will automatically create on boot) will use 1G of your 8G of RAM. If you now try to create another VM (say ''VM_1'') with 2G of RAM, it will just do that, and you''ll have 1G +2G=3G out of 8G of your RAM dedicated to these two VMs, while the other 5G are still free. Have you tried that? If you do, try running `xl info'' on Dom0 again after that. Try also SSH-ing in ''VM_1'' and asking (e.g., via `free -m'') how many total and free memory it has. As one should expect, it will say it has 2GB of RAM in total... Does this make sense? So, again, the reason why you''re not seeing 7GB of RAM in Dom0 is because they''re not there! Dom0 is a virtual machine to which you''ve given 1GB of RAM via the cmdline... Having only 1GB of RAM is just doing right what you asked for! I can understand that it might look a bit tricky, but what you seem to be missing here is you should consider Dom0 pretty much like any other VM that Xen is managing as the hypervisor. Hope of being of some help. Regards, Dario -- Those were interesting articles. I''m left with a couple questions. 1) How does one determine how much memory to allocate? 2) Is there a way to garauntee that dom0 never has to use a page file? 3) Sorry for the unrelated component - That wiki page was great. When building for the most current version of Xen, what is a good way to find all the related wiki pages? Ray
Hello, There is still a bug. For example I have 16Gb RAM, 512 dedicated to Dom0, 2 Gb dedicated to VM1 which leaves me this amount of RAM Xl info total_memory : 15869 free_memory : 13124 this is correct as 512MB is missing because it is assigned to Dom0. Now I create a new config file for VM2 and I set the RAM memory = 12288 Now this should be fine and allow me to boot the VM as I should still have a bit of memory left over. Xl create vm2 libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold failed to free memory for the domain Why it is trying to take memory from dom0?? Thanks Ian -----Original Message----- From: xen-users-bounces@lists.xen.org [mailto:xen-users-bounces@lists.xen.org] On Behalf Of ray@aarden.us Sent: 11 May 2012 00:56 To: xen-users@lists.xen.org Subject: Re: [Xen-users] Dom0 Memory? On Wed, 2012-05-09 at 17:52 +0200, Flavio wrote:> > What does ''xm info'' say? > # xl info > total_memory : 8107 > free_memory : 6968 >So, 8GB of RAM is what Xen knows, ~7 of them being free... What''s the problem?> As you can see, my 8GB of RAM have disappeared. > What can you say about that? >Uh? :-O Ok, this might be a bit too technical, but perhaps still of help: http://blog.xen.org/index.php/2012/04/30/do%EF%BB%BFm0-memory-where-it-has-not-gone/ I''m also sure this has been mentioned in this or another thread related to this "issue": http://wiki.xen.org/wiki/Xen_Best_Practices http://wiki.xen.org/wiki/Xen_Best_Practices#Why_should_I_dedicate_fixed_amount_of_memory_for_Xen_dom0.3F Also trying to quickly summarize what''s happening, no, your memory _has_not_ disappeared. Actually, it is right there for your VMs to use it (and xl invocation above shows right that). With dom0_mem=1G you told Xen that one of your VM (the one that it will automatically call ''Domain0'' and that it will automatically create on boot) will use 1G of your 8G of RAM. If you now try to create another VM (say ''VM_1'') with 2G of RAM, it will just do that, and you''ll have 1G +2G=3G out of 8G of your RAM dedicated to these two VMs, while the other 5G are still free. Have you tried that? If you do, try running `xl info'' on Dom0 again after that. Try also SSH-ing in ''VM_1'' and asking (e.g., via `free -m'') how many total and free memory it has. As one should expect, it will say it has 2GB of RAM in total... Does this make sense? So, again, the reason why you''re not seeing 7GB of RAM in Dom0 is because they''re not there! Dom0 is a virtual machine to which you''ve given 1GB of RAM via the cmdline... Having only 1GB of RAM is just doing right what you asked for! I can understand that it might look a bit tricky, but what you seem to be missing here is you should consider Dom0 pretty much like any other VM that Xen is managing as the hypervisor. Hope of being of some help. Regards, Dario -- Those were interesting articles. I''m left with a couple questions. 1) How does one determine how much memory to allocate? 2) Is there a way to garauntee that dom0 never has to use a page file? 3) Sorry for the unrelated component - That wiki page was great. When building for the most current version of Xen, what is a good way to find all the related wiki pages? Ray _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote:> Hello, > > There is still a bug. > > For example I have 16Gb RAM, 512 dedicated to Dom0, 2 Gb dedicated to VM1 which leaves me this amount of RAM > > Xl info > > total_memory : 15869 > free_memory : 13124 > > this is correct as 512MB is missing because it is assigned to Dom0. > > Now I create a new config file for VM2 and I set the RAM > > memory = 12288 > > Now this should be fine and allow me to boot the VM as I should still have a bit of memory left over. > > Xl create vm2 > > > libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold > > libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold > > libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold > > failed to free memory for the domain > > Why it is trying to take memory from dom0??You need to set "autoballoon=0" in /etc/xen/xl.conf if you don''t want xl to automatically balloon dom0 down when starting a domain -- for example if you use the dom0_mem option. Ian.
Ian, You’re a legend! This has been giving me grief for a long time, had no idea of this setting. Thanks Ian -----Original Message----- From: Ian Campbell [mailto:Ian.Campbell@citrix.com] Sent: 11 May 2012 09:27 To: Ian Tobin Cc: ray@aarden.us; xen-users@lists.xen.org Subject: Re: [Xen-users] Dom0 Memory? On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote:> Hello, > > There is still a bug. > > For example I have 16Gb RAM, 512 dedicated to Dom0, 2 Gb dedicated to > VM1 which leaves me this amount of RAM > > Xl info > > total_memory : 15869 > free_memory : 13124 > > this is correct as 512MB is missing because it is assigned to Dom0. > > Now I create a new config file for VM2 and I set the RAM > > memory = 12288 > > Now this should be fine and allow me to boot the VM as I should still have a bit of memory left over. > > Xl create vm2 > > > libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for > dom0 is below the minimum threshold > > libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for > dom0 is below the minimum threshold > > libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for > dom0 is below the minimum threshold > > failed to free memory for the domain > > Why it is trying to take memory from dom0??You need to set "autoballoon=0" in /etc/xen/xl.conf if you don't want xl to automatically balloon dom0 down when starting a domain -- for example if you use the dom0_mem option. Ian. _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote:> You’re a legend! This has been giving me grief for a long time, had no > idea of this setting.Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... Ian. _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
It was just something ive always set, but the wiki is out of date http://wiki.xensource.com/xenwiki/XenBestPractices at the top it mentions about the autoballooing but no mention of the /etc/xen/xl.conf or to that point any mention of xl at all. Thanks Ian -----Original Message----- From: Ian Campbell [mailto:Ian.Campbell@citrix.com] Sent: 11 May 2012 10:04 To: Ian Tobin Cc: ray@aarden.us; xen-users@lists.xen.org Subject: RE: [Xen-users] Dom0 Memory? On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote:> You’re a legend! This has been giving me grief for a long time, had no > idea of this setting.Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... Ian. _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Fri, 2012-05-11 at 10:07 +0100, Ian Tobin wrote:> It was just something ive always set, but the wiki is out of date > > http://wiki.xensource.com/xenwiki/XenBestPractices > > at the top it mentions about the autoballooing but no mention of the /etc/xen/xl.conf or to that point any mention of xl at all.Thanks, that's actually a static copy of the old wiki, however http://wiki.xen.org/wiki/XenBestPractices also has the same issue AFAICT so I'll update that. Cheers, Ian.> > Thanks > > Ian > > > > -----Original Message----- > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > Sent: 11 May 2012 10:04 > To: Ian Tobin > Cc: ray@aarden.us; xen-users@lists.xen.org > Subject: RE: [Xen-users] Dom0 Memory? > > On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote: > > You’re a legend! This has been giving me grief for a long time, had no > > idea of this setting. > > Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... > > Ian. > >_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Fri, May 11, 2012 at 3:27 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote:> On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote:>> Xl info >> >> total_memory : 15869 >> free_memory : 13124>> Now I create a new config file for VM2 and I set the RAM >> >> memory = 12288>> libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is below the minimum threshold >> >> failed to free memory for the domain >> >> Why it is trying to take memory from dom0?? > > You need to set "autoballoon=0" in /etc/xen/xl.conf if you don''t want xl > to automatically balloon dom0 down when starting a domain -- for example > if you use the dom0_mem option. > > Ian.Isn''t that a bug? Shouldn''t xl try to use free_memory first, and only try to baloon-down memory from dom0 if it still needs more? -- Fajar
On 11 May 2012 10:27, Ian Campbell <Ian.Campbell@citrix.com> wrote:> You need to set "autoballoon=0" in /etc/xen/xl.conf if you don''t want xl > to automatically balloon dom0 down when starting a domain -- for example > if you use the dom0_mem option.Wow! Great hint. I dindn''t know that too! Set to 0, immediately. On 11 May 2012 11:35, Fajar A. Nugraha <list@fajar.net> wrote:> > Isn''t that a bug? Shouldn''t xl try to use free_memory first, and only > try to baloon-down memory from dom0 if it still needs more?This is a very good question. What about that? -- Flavio
You may want to mention about the dom0_mem=512M,max:512M This stops the dom0 memory disappearing Thanks Ian -----Original Message----- From: Ian Campbell [mailto:Ian.Campbell@citrix.com] Sent: 11 May 2012 10:20 To: Ian Tobin Cc: ray@aarden.us; xen-users@lists.xen.org Subject: RE: [Xen-users] Dom0 Memory? On Fri, 2012-05-11 at 10:07 +0100, Ian Tobin wrote:> It was just something ive always set, but the wiki is out of date > > http://wiki.xensource.com/xenwiki/XenBestPractices > > at the top it mentions about the autoballooing but no mention of the /etc/xen/xl.conf or to that point any mention of xl at all.Thanks, that's actually a static copy of the old wiki, however http://wiki.xen.org/wiki/XenBestPractices also has the same issue AFAICT so I'll update that. Cheers, Ian.> > Thanks > > Ian > > > > -----Original Message----- > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > Sent: 11 May 2012 10:04 > To: Ian Tobin > Cc: ray@aarden.us; xen-users@lists.xen.org > Subject: RE: [Xen-users] Dom0 Memory? > > On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote: > > You’re a legend! This has been giving me grief for a long time, had > > no idea of this setting. > > Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... > > Ian. > >_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
It does seem to be a bug as it didn''t used to happen with xm Thanks Ian -----Original Message----- From: xen-users-bounces@lists.xen.org [mailto:xen-users-bounces@lists.xen.org] On Behalf Of Fajar A. Nugraha Sent: 11 May 2012 10:36 To: Ian Campbell Cc: xen-users@lists.xen.org Subject: Re: [Xen-users] Dom0 Memory? On Fri, May 11, 2012 at 3:27 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote:> On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote:>> Xl info >> >> total_memory : 15869 >> free_memory : 13124>> Now I create a new config file for VM2 and I set the RAM >> >> memory = 12288>> libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for >> dom0 is below the minimum threshold >> >> failed to free memory for the domain >> >> Why it is trying to take memory from dom0?? > > You need to set "autoballoon=0" in /etc/xen/xl.conf if you don''t want > xl to automatically balloon dom0 down when starting a domain -- for > example if you use the dom0_mem option. > > Ian.Isn''t that a bug? Shouldn''t xl try to use free_memory first, and only try to baloon-down memory from dom0 if it still needs more? -- Fajar _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Fri, 2012-05-11 at 11:26 +0100, Ian Tobin wrote:> You may want to mention about the dom0_mem=512M,max:512MThe active wiki page seems to mention that already, is it inaccurate? Please feel free to edit the wiki if so.> > This stops the dom0 memory disappearing > > Thanks > > Ian > > -----Original Message----- > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > Sent: 11 May 2012 10:20 > To: Ian Tobin > Cc: ray@aarden.us; xen-users@lists.xen.org > Subject: RE: [Xen-users] Dom0 Memory? > > On Fri, 2012-05-11 at 10:07 +0100, Ian Tobin wrote: > > It was just something ive always set, but the wiki is out of date > > > > http://wiki.xensource.com/xenwiki/XenBestPractices > > > > at the top it mentions about the autoballooing but no mention of the /etc/xen/xl.conf or to that point any mention of xl at all. > > Thanks, that's actually a static copy of the old wiki, however http://wiki.xen.org/wiki/XenBestPractices also has the same issue AFAICT so I'll update that. > > Cheers, > Ian. > > > > > Thanks > > > > Ian > > > > > > > > -----Original Message----- > > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > > Sent: 11 May 2012 10:04 > > To: Ian Tobin > > Cc: ray@aarden.us; xen-users@lists.xen.org > > Subject: RE: [Xen-users] Dom0 Memory? > > > > On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote: > > > You’re a legend! This has been giving me grief for a long time, had > > > no idea of this setting. > > > > Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... > > > > Ian. > > > > > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Fri, 2012-05-11 at 11:28 +0100, Ian Campbell wrote:> On Fri, 2012-05-11 at 11:26 +0100, Ian Tobin wrote: > > You may want to mention about the dom0_mem=512M,max:512M > > The active wiki pageby which I mean http://wiki.xen.org/wiki/XenBestPractices rather than http://wiki.xensource.com/xenwiki/XenBestPractices. IUan.> seems to mention that already, is it inaccurate? > > Please feel free to edit the wiki if so. > > > > > This stops the dom0 memory disappearing > > > > Thanks > > > > Ian > > > > -----Original Message----- > > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > > Sent: 11 May 2012 10:20 > > To: Ian Tobin > > Cc: ray@aarden.us; xen-users@lists.xen.org > > Subject: RE: [Xen-users] Dom0 Memory? > > > > On Fri, 2012-05-11 at 10:07 +0100, Ian Tobin wrote: > > > It was just something ive always set, but the wiki is out of date > > > > > > http://wiki.xensource.com/xenwiki/XenBestPractices > > > > > > at the top it mentions about the autoballooing but no mention of the /etc/xen/xl.conf or to that point any mention of xl at all. > > > > Thanks, that's actually a static copy of the old wiki, however http://wiki.xen.org/wiki/XenBestPractices also has the same issue AFAICT so I'll update that. > > > > Cheers, > > Ian. > > > > > > > > Thanks > > > > > > Ian > > > > > > > > > > > > -----Original Message----- > > > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > > > Sent: 11 May 2012 10:04 > > > To: Ian Tobin > > > Cc: ray@aarden.us; xen-users@lists.xen.org > > > Subject: RE: [Xen-users] Dom0 Memory? > > > > > > On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote: > > > > You’re a legend! This has been giving me grief for a long time, had > > > > no idea of this setting. > > > > > > Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... > > > > > > Ian. > > > > > > > > > > > > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xen.org > http://lists.xen.org/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
Sorry yes your right, didn’t see that Thanks Ian -----Original Message----- From: Ian Campbell [mailto:Ian.Campbell@citrix.com] Sent: 11 May 2012 11:34 To: Ian Tobin Cc: xen-users@lists.xen.org; ray@aarden.us Subject: Re: [Xen-users] Dom0 Memory? On Fri, 2012-05-11 at 11:28 +0100, Ian Campbell wrote:> On Fri, 2012-05-11 at 11:26 +0100, Ian Tobin wrote: > > You may want to mention about the dom0_mem=512M,max:512M > > The active wiki pageby which I mean http://wiki.xen.org/wiki/XenBestPractices rather than http://wiki.xensource.com/xenwiki/XenBestPractices. IUan.> seems to mention that already, is it inaccurate? > > Please feel free to edit the wiki if so. > > > > > This stops the dom0 memory disappearing > > > > Thanks > > > > Ian > > > > -----Original Message----- > > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > > Sent: 11 May 2012 10:20 > > To: Ian Tobin > > Cc: ray@aarden.us; xen-users@lists.xen.org > > Subject: RE: [Xen-users] Dom0 Memory? > > > > On Fri, 2012-05-11 at 10:07 +0100, Ian Tobin wrote: > > > It was just something ive always set, but the wiki is out of date > > > > > > http://wiki.xensource.com/xenwiki/XenBestPractices > > > > > > at the top it mentions about the autoballooing but no mention of the /etc/xen/xl.conf or to that point any mention of xl at all. > > > > Thanks, that's actually a static copy of the old wiki, however http://wiki.xen.org/wiki/XenBestPractices also has the same issue AFAICT so I'll update that. > > > > Cheers, > > Ian. > > > > > > > > Thanks > > > > > > Ian > > > > > > > > > > > > -----Original Message----- > > > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > > > Sent: 11 May 2012 10:04 > > > To: Ian Tobin > > > Cc: ray@aarden.us; xen-users@lists.xen.org > > > Subject: RE: [Xen-users] Dom0 Memory? > > > > > > On Fri, 2012-05-11 at 09:49 +0100, Ian Tobin wrote: > > > > You’re a legend! This has been giving me grief for a long time, > > > > had no idea of this setting. > > > > > > Out of interest where did you see the dom0_mem= recommendation without mention of the autoballoon setting? We should try and update those which we can to mention both together... > > > > > > Ian. > > > > > > > > > > > > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xen.org > http://lists.xen.org/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 11 May 2012 12:26, Ian Tobin <itobin@tidyhosts.com> wrote:> You may want to mention about the dom0_mem=512M,max:512M > > This stops the dom0 memory disappearingMmh, I guess this fix didn''t work for me. And even setting autoballoon=0 didn''t change anything on my system. Actually cat /proc/meminfo still gives me this: MemTotal: 946536 kB which is less than 1GB. And I have 8GB on my laptop. -- Flavio
It wont be exactly 1g but its fairly close Ian -----Original Message----- From: Flavio [mailto:fbcyborg@gmail.com] Sent: 11 May 2012 11:42 To: Ian Tobin Cc: Ian Campbell; xen-users@lists.xen.org; ray@aarden.us Subject: Re: [Xen-users] Dom0 Memory? On 11 May 2012 12:26, Ian Tobin <itobin@tidyhosts.com> wrote:> You may want to mention about the dom0_mem=512M,max:512M > > This stops the dom0 memory disappearingMmh, I guess this fix didn''t work for me. And even setting autoballoon=0 didn''t change anything on my system. Actually cat /proc/meminfo still gives me this: MemTotal: 946536 kB which is less than 1GB. And I have 8GB on my laptop. -- Flavio
On Fri, 2012-05-11 at 12:41 +0200, Flavio wrote:> On 11 May 2012 12:26, Ian Tobin <itobin@tidyhosts.com> wrote: > > You may want to mention about the dom0_mem=512M,max:512M > > > > This stops the dom0 memory disappearing > Mmh, I guess this fix didn''t work for me. And even setting > autoballoon=0 didn''t change anything on my system. > Actually cat /proc/meminfo still gives me this: > MemTotal: 946536 kB > which is less than 1GB. And I have 8GB on my laptop. >While still using dom0_mem=1GB or not on the Xen bootline? Or even without it? Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 11 May 2012 16:22, Dario Faggioli <raistlin@linux.it> wrote:> While still using dom0_mem=1GB or not on the Xen bootline? Or even > without it?I''ve tried only while using dom0_mem=1GB,max:1GB. I didn''t try without such option and with autoballoning=0. -- Flavio
On Fri, 2012-05-11 at 16:39 +0200, Flavio wrote:> On 11 May 2012 16:22, Dario Faggioli <raistlin@linux.it> wrote: > > While still using dom0_mem=1GB or not on the Xen bootline? Or even > > without it? > I''ve tried only while using dom0_mem=1GB,max:1GB. > I didn''t try without such option and with autoballoning=0. >Then again, autoballooning or not, /proc/meminfo on Dom0 saying 1GB is consistent with you passing dom0_mem=1GB[,max:1GB] Dario -- <<This happens because I choose it to happen!>> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On 11 May 2012 16:54, Dario Faggioli <raistlin@linux.it> wrote:> Then again, autoballooning or not, /proc/meminfo on Dom0 saying 1GB is > consistent with you passing dom0_mem=1GB[,max:1GB]OK! ;-) -- Flavio
> On Fri, May 11, 2012 at 3:27 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote: > > On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote: > > >> Xl info > >> > >> total_memory : 15869 > >> free_memory : 13124 > > > >> Now I create a new config file for VM2 and I set the RAM > >> > >> memory = 12288 > > >> libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is > below the minimum threshold > >> > >> failed to free memory for the domain > >> > >> Why it is trying to take memory from dom0?? > > > > You need to set "autoballoon=0" in /etc/xen/xl.conf if you don''t want xl > > to automatically balloon dom0 down when starting a domain -- for example > > if you use the dom0_mem option. > > > > Ian. > > Isn''t that a bug? Shouldn''t xl try to use free_memory first, and only > try to baloon-down memory from dom0 if it still needs more?Even if this is an unsupported configuration, it could actually be a bug. Could you please post the output of xenstore-ls? --8323329-70939622-1336754238=:26786 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users --8323329-70939622-1336754238=:26786--
On Fri, 11 May 2012, Stefano Stabellini wrote:> > On Fri, May 11, 2012 at 3:27 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote: > > > On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote: > > > > >> Xl info > > >> > > >> total_memory : 15869 > > >> free_memory : 13124 > > > > > > >> Now I create a new config file for VM2 and I set the RAM > > >> > > >> memory = 12288 > > > > >> libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is > > below the minimum threshold > > >> > > >> failed to free memory for the domain > > >> > > >> Why it is trying to take memory from dom0?? > > > > > > You need to set "autoballoon=0" in /etc/xen/xl.conf if you don''t want xl > > > to automatically balloon dom0 down when starting a domain -- for example > > > if you use the dom0_mem option. > > > > > > Ian. > > > > Isn''t that a bug? Shouldn''t xl try to use free_memory first, and only > > try to baloon-down memory from dom0 if it still needs more? > > Even if this is an unsupported configuration, it could actually be a > bug. > Could you please post the output of xenstore-ls?I didn''t notice that you are actually trying to create a 12G VM. The problem is that autoballoon=1 in xl.conf is fundamentally incompatible with dom0_mem on the Xen command line. The reason is that autoballoon calculates the amount of memory that should be left free on the system but measuring how much memory is free after dom0 boots, assuming that dom0 gets all the memory. So if you pass dom0_mem=512M, then at boot time the free memory is 16G-512M => 15.5G. Not so long ago xl autoballoon would have tried to keep 15.5G of memory free in the system at all times, therefore preventing you from starting any guests at all. Fortunately we have a safety net for wrong configurations like this one: the amount of memory that should be left free in the system is capped to 15% of the total memory, in this case 0.15*16G => 2.4G. So the reason why you cannot start a 12G guest is that 12G > 13124M - 2.4G. --8323329-58003784-1336754831=:26786 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users --8323329-58003784-1336754831=:26786--
Ok makes sense now, I didn't realise it wasn't compatible anymore as I'm sure many others didn't but as a default config once compiled with dom_mem being recommended as best practice it is easy to fall into the trap I guess. Thanks Ian Tidyhosts UK - Server & Web Specialists W: www.tidyhosts.com E: enquiries@tidyhosts.com T: 0871 910 6732 This email and its attachments are scanned by TidyHosts UK. All emails and attachments should also be scanned by the recipient. TidyHosts UK accept no responsibility for any damage caused by any virus attached to this email. This email is confidential and is intended only for the addressee(s). On 11 May 2012, at 17:48, "Stefano Stabellini" <stefano.stabellini@eu.citrix.com> wrote:> On Fri, 11 May 2012, Stefano Stabellini wrote: >>> On Fri, May 11, 2012 at 3:27 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote: >>>> On Fri, 2012-05-11 at 09:11 +0100, Ian Tobin wrote: >>> >>>>> Xl info >>>>> >>>>> total_memory      : 15869 >>>>> free_memory       : 13124 >>> >>> >>>>> Now I create a new config file for VM2 and I set the RAM >>>>> >>>>> memory = 12288 >>> >>>>> libxl: error: libxl.c:2150:libxl_set_memory_target new target 0 for dom0 is >>> below the minimum threshold >>>>> >>>>> failed to free memory for the domain >>>>> >>>>> Why it is trying to take memory from dom0?? >>>> >>>> You need to set "autoballoon=0" in /etc/xen/xl.conf if you don't want xl >>>> to automatically balloon dom0 down when starting a domain -- for example >>>> if you use the dom0_mem option. >>>> >>>> Ian. >>> >>> Isn't that a bug? Shouldn't xl try to use free_memory first, and only >>> try to baloon-down memory from dom0 if it still needs more? >> >> Even if this is an unsupported configuration, it could actually be a >> bug. >> Could you please post the output of xenstore-ls? > > I didn't notice that you are actually trying to create a 12G VM. > > The problem is that autoballoon=1 in xl.conf is fundamentally > incompatible with dom0_mem on the Xen command line. > > The reason is that autoballoon calculates the amount of memory that > should be left free on the system but measuring how much memory is free > after dom0 boots, assuming that dom0 gets all the memory. > So if you pass dom0_mem=512M, then at boot time the free memory is > 16G-512M => 15.5G. > Not so long ago xl autoballoon would have tried to keep 15.5G of memory > free in the system at all times, therefore preventing you from starting > any guests at all. > Fortunately we have a safety net for wrong configurations like this one: > the amount of memory that should be left free in the system is capped to > 15% of the total memory, in this case 0.15*16G => 2.4G. > > So the reason why you cannot start a 12G guest is that 12G > 13124M - 2.4G. > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xen.org > http://lists.xen.org/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users