I have a xen server setup that I want to install a lot of vms on if possible. The vms will have no utilization for the most part; and brief utilization when active. The server has 2GB of RAM. We were running into a problem were the dom0 would not let us add anymore vms because we were out of physical memory. I have started to read about memory ballooning and hoping someone could point me in the right direction. If my understanding is correct, ballooning will increase the vm memory if needed up to a maxmem setting. And can decrease memory if requested by the dom0. Is this an automatic process, or do I have to manually issue a command to increase/decrease the domU memory? The command I know about is: > xm mem-set <Domain> <Mem> Thanks, Chris.... _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Jul 17, 2008, at 16:35 , Chris Hane wrote:> I have a xen server setup that I want to install a lot of vms on if > possible. The vms will have no utilization for the most part; and > brief utilization when active. The server has 2GB of RAM. > > We were running into a problem were the dom0 would not let us add > anymore vms because we were out of physical memory. > > I have started to read about memory ballooning and hoping someone > could point me in the right direction. If my understanding is > correct, ballooning will increase the vm memory if needed up to a > maxmem setting. And can decrease memory if requested by the dom0. > > Is this an automatic process, or do I have to manually issue a > command to increase/decrease the domU memory? The command I know > about is: > > xm mem-set <Domain> <Mem>There is no automatic process for increasing guest memory, yet. As Mark mentioned yesterday there are some patches floating around to do this if someone wants to try it out. cheers, robert _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Robert Read wrote:> > On Jul 17, 2008, at 16:35 , Chris Hane wrote: > >> I have a xen server setup that I want to install a lot of vms on if >> possible. The vms will have no utilization for the most part; and >> brief utilization when active. The server has 2GB of RAM. >> >> We were running into a problem were the dom0 would not let us add >> anymore vms because we were out of physical memory. >> >> I have started to read about memory ballooning and hoping someone >> could point me in the right direction. If my understanding is >> correct, ballooning will increase the vm memory if needed up to a >> maxmem setting. And can decrease memory if requested by the dom0. >> >> Is this an automatic process, or do I have to manually issue a >> command to increase/decrease the domU memory? The command I know >> about is: >> > xm mem-set <Domain> <Mem> > > There is no automatic process for increasing guest memory, yet. As > Mark mentioned yesterday there are some patches floating around to do > this if someone wants to try it out.xenballoond was committed to xen-unstable for the next release. It was designed for pretty much this exact reason. Details: http://wiki.xensource.com/xenwiki/Open_Topics_For_Discussion?action=AttachFile&do=get&target=Memory+Overcommit.pdf Thanks, Matt _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Matt Ayres wrote:> Robert Read wrote: >> >> On Jul 17, 2008, at 16:35 , Chris Hane wrote: >> >>> I have a xen server setup that I want to install a lot of vms on if >>> possible. The vms will have no utilization for the most part; and >>> brief utilization when active. The server has 2GB of RAM. >>> >>> We were running into a problem were the dom0 would not let us add >>> anymore vms because we were out of physical memory. >>> >>> I have started to read about memory ballooning and hoping someone >>> could point me in the right direction. If my understanding is >>> correct, ballooning will increase the vm memory if needed up to a >>> maxmem setting. And can decrease memory if requested by the dom0. >>> >>> Is this an automatic process, or do I have to manually issue a >>> command to increase/decrease the domU memory? The command I know >>> about is: >>> > xm mem-set <Domain> <Mem> >> >> There is no automatic process for increasing guest memory, yet. As >> Mark mentioned yesterday there are some patches floating around to do >> this if someone wants to try it out. > xenballoond was committed to xen-unstable for the next release. It was > designed for pretty much this exact reason. > > Details: > http://wiki.xensource.com/xenwiki/Open_Topics_For_Discussion?action=AttachFile&do=get&target=Memory+Overcommit.pdf >Thanks for the information. This could be why I couldn''t find any information about automatic ballooning :) Chris.... _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Friday 18 July 2008, Chris Hane wrote:> I have a xen server setup that I want to install a lot of vms on if > possible. The vms will have no utilization for the most part; and brief > utilization when active. The server has 2GB of RAM. > > We were running into a problem were the dom0 would not let us add anymore > vms because we were out of physical memory. > > I have started to read about memory ballooning and hoping someone could > point me in the right direction. If my understanding is correct, > ballooning will increase the vm memory if needed up to a maxmem setting. > And can decrease memory if requested by the dom0. > > Is this an automatic process, or do I have to manually issue a command to > > increase/decrease the domU memory? The command I know about is: > > xm mem-set <Domain> <Mem>Normally you can''t grow a Linux guest beyond its initial allocation because it won''t have sized its internal datastructures to fit the extra memory. You can either start the guest at the largest you''ll ever want it, then shrink it if required, or you can pass "mem=<something>" on the kernel command line to tell it the largest memory it should prepare to cope with (e.g. mem=4G). mem-max is just a "safety catch" that prevents the domain from resizing itself and stealing lots of memory. It doesn''t change what the domain is capable of handling. Cheers, Mark -- Push Me Pull You - Distributed SCM tool (http://www.cl.cam.ac.uk/~maw48/pmpu/) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Matt Ayres wrote:> Robert Read wrote: >> >> On Jul 17, 2008, at 16:35 , Chris Hane wrote: >> >>> I have a xen server setup that I want to install a lot of vms on if >>> possible. The vms will have no utilization for the most part; and >>> brief utilization when active. The server has 2GB of RAM. >>> >>> We were running into a problem were the dom0 would not let us add >>> anymore vms because we were out of physical memory. >>> >>> I have started to read about memory ballooning and hoping someone >>> could point me in the right direction. If my understanding is >>> correct, ballooning will increase the vm memory if needed up to a >>> maxmem setting. And can decrease memory if requested by the dom0. >>> >>> Is this an automatic process, or do I have to manually issue a >>> command to increase/decrease the domU memory? The command I know >>> about is: >>> > xm mem-set <Domain> <Mem> >> >> There is no automatic process for increasing guest memory, yet. As >> Mark mentioned yesterday there are some patches floating around to do >> this if someone wants to try it out. > xenballoond was committed to xen-unstable for the next release. It was > designed for pretty much this exact reason. > > Details: > http://wiki.xensource.com/xenwiki/Open_Topics_For_Discussion?action=AttachFile&do=get&target=Memory+Overcommit.pdf > > > Thanks, > Matt >I have read the pdf you linked to and am excited to try out the scripts. One question, do you know if the scripts rely on functionality/interfaces in xen-unstable or could the potentially work on xen 3.x (I am running 3.1.4)? Thanks for pointing me to this. Chris.... _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users