----- Original Message ----- > From: "Andrew Cathrow" <acath...@redhat.com> > To: "Sander Grendelman" <san...@grendelman.com> > Cc: users@ovirt.org > Sent: Monday, December 16, 2013 2:05:00 PM > Subject: Re: [Users] hot add ram to a vm > > > > ----- Original Message ----- > > From: "Sander Grendelman" <san...@grendelman.com> > > To: "Michal Skrivanek" <michal.skriva...@redhat.com> > > Cc: users@ovirt.org > > Sent: Friday, December 13, 2013 8:52:42 AM > > Subject: Re: [Users] hot add ram to a vm > > > > On Fri, Dec 13, 2013 at 1:42 PM, Michal Skrivanek > > <michal.skriva...@redhat.com> wrote: > > > Too bad QEMU doesn't support it. So it's still a long way. > > > > qemu/libvirt "kind of" supports it (at least in F19). > > > > In virt-manager you can define "current" and "maximum" memory > > allocation. > > > > The VM only sees the current allocation and you can hot add memory up > > to the maximum allocation. > > > It isn't really hot-plug. > This allows you to statically set the physical ram but then use the balloon > device to "borrow" some ram from the guest. > If max memory was 4gb and we set current memory to 2gb the VM would still see > 4gb of physical memory but the balloon driver would be taking up 2gb of > memory in the guest, this memory would be returned to the host for other VMs > to use. > >
Right, currentMemory is how you manipulate the balloon: http://libvirt.org/formatdomain.html#elementsMemoryAllocation Note that is requires an agent, a driver and cooperation from the guest. > > > > Example from the xml definition: > > > > <memory unit='KiB'>3145728</memory> > > <currentMemory unit='KiB'>1048576</currentMemory> > > > > After booting: > > > > [root@grkvm201 ~]# uname -a > > Linux grkvm201.plusine.intern 2.6.32-358.23.2.el6.x86_64 #1 SMP Wed > > Oct 16 18:37:12 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux > > [root@grkvm201 ~]# free -lm > > total used free shared buffers > > cached > > Mem: 837 296 540 0 8 > > 84 > > Low: 837 296 540 > > High: 0 0 0 > > -/+ buffers/cache: 203 634 > > Swap: 511 0 511 > > [root@grkvm201 ~]# > > > > memory increased to 2GB through virt-manager: > > > > [root@grkvm201 ~]# free -lm > > total used free shared buffers > > cached > > Mem: 1861 295 1565 0 8 > > 84 > > Low: 1861 295 1565 > > High: 0 0 0 > > -/+ buffers/cache: 202 1659 > > Swap: 511 0 511 > > [root@grkvm201 ~]# cat /proc/meminfo > > MemTotal: 1906176 kB > > MemFree: 1603456 kB > > Buffers: 9140 kB > > Cached: 86860 kB > > SwapCached: 0 kB > > Active: 92564 kB > > Inactive: 68064 kB > > Active(anon): 68692 kB > > Inactive(anon): 12 kB > > Active(file): 23872 kB > > Inactive(file): 68052 kB > > Unevictable: 21600 kB > > Mlocked: 11380 kB > > SwapTotal: 524280 kB > > SwapFree: 524280 kB > > Dirty: 12 kB > > Writeback: 0 kB > > AnonPages: 86232 kB > > Mapped: 20436 kB > > Shmem: 288 kB > > Slab: 75132 kB > > SReclaimable: 14576 kB > > SUnreclaim: 60556 kB > > KernelStack: 1464 kB > > PageTables: 4224 kB > > NFS_Unstable: 0 kB > > Bounce: 0 kB > > WritebackTmp: 0 kB > > CommitLimit: 1477368 kB > > Committed_AS: 547624 kB > > VmallocTotal: 34359738367 kB > > VmallocUsed: 20040 kB > > VmallocChunk: 34359688500 kB > > HardwareCorrupted: 0 kB > > AnonHugePages: 18432 kB > > HugePages_Total: 0 > > HugePages_Free: 0 > > HugePages_Rsvd: 0 > > > > Memory decreased to 1,5GB through virt-manager: > > [root@grkvm201 ~]# free -lm > > total used free shared buffers > > cached > > Mem: 1349 295 1054 0 8 > > 84 > > Low: 1349 295 1054 > > High: 0 0 0 > > -/+ buffers/cache: 201 1147 > > Swap: 511 0 511 > > [root@grkvm201 ~]# > > _______________________________________________ > > Users mailing list > > Users@ovirt.org > > http://lists.ovirt.org/mailman/listinfo/users > > > > > > > _______________________________________________ > Users mailing list > Users@ovirt.org > http://lists.ovirt.org/mailman/listinfo/users > _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users