----- Original Message -----
From: "Andrew Cathrow" <acathrow@redhat.com> To: "Sander Grendelman" <sander@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" <sander@grendelman.com> To: "Michal Skrivanek" <michal.skrivanek@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.skrivanek@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
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