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. 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 sharedbuffers cached Mem: 837296540 0 8 84 Low: 837296540 High:0 0 0 -/+ buffers/cache:203634 Swap: 511 0511 [root@grkvm201 ~]# memory increased to 2GB through virt-manager: [root@grkvm201 ~]# free -lm total used free sharedbuffers cached Mem: 1861295 1565 0 8 84 Low: 1861295 1565 High:0 0 0 -/+ buffers/cache:202 1659 Swap: 511 0511 [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 sharedbuffers cached Mem: 1349295 1054 0 8 84 Low: 1349295 1054 High:0 0 0 -/+ buffers/cache:201 1147 Swap: 511 0511 [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
Re: [Users] hot add ram to a vm
- 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 sharedbuffers cached Mem: 837296540 0 8 84 Low: 837296540 High:0 0 0 -/+ buffers/cache:203634 Swap: 511 0511 [root@grkvm201 ~]# memory increased to 2GB through virt-manager: [root@grkvm201 ~]# free -lm total used free sharedbuffers cached Mem: 1861295 1565 0 8 84 Low: 1861295 1565 High:0 0 0 -/+ buffers/cache:202 1659 Swap: 511 0511 [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 sharedbuffers cached Mem: 1349295 1054 0 8 84 Low: 1349295 1054 High:0 0 0 -/+ buffers/cache:201 1147 Swap: 511 0511 [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
Re: [Users] hot add ram to a vm
Too bad QEMU doesn't support it. So it's still a long way. Balloon should be able to cover most of the use cases. You have overcommit and can reserve only a part of RAM, then change the reserved amount which adds more RAM resources. OS still sees the same (maximum) size, but effectively it allows similar usage as hot add ram Thanks, michal On Dec 12, 2013, at 23:38 , Sigbjorn Lie sigbj...@nixtra.com wrote: +1 for this feature On 10/12/13 10:00, Sven Kieske wrote: Hi, just want to say that we are also interested in this feature. ___ 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
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. 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 sharedbuffers cached Mem: 837296540 0 8 84 Low: 837296540 High:0 0 0 -/+ buffers/cache:203634 Swap: 511 0511 [root@grkvm201 ~]# memory increased to 2GB through virt-manager: [root@grkvm201 ~]# free -lm total used free sharedbuffers cached Mem: 1861295 1565 0 8 84 Low: 1861295 1565 High:0 0 0 -/+ buffers/cache:202 1659 Swap: 511 0511 [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 sharedbuffers cached Mem: 1349295 1054 0 8 84 Low: 1349295 1054 High:0 0 0 -/+ buffers/cache:201 1147 Swap: 511 0511 [root@grkvm201 ~]# ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
[Users] hot add ram to a vm
Hello, Is hot add ram to a vm is supported by ovirt, or is it planned to be? -- Nathanaël Blanchet Supervision réseau Pôle exploitation et maintenance Département des systèmes d'information 227 avenue Professeur-Jean-Louis-Viala 34193 MONTPELLIER CEDEX 5 Tél. 33 (0)4 67 54 84 55 Fax 33 (0)4 67 54 84 14 blanc...@abes.fr ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [Users] hot add ram to a vm
On Mon, Dec 09, 2013 at 05:27:16PM +0100, Nathanaël Blanchet wrote: Hello, Is hot add ram to a vm is supported by ovirt, or is it planned to be? Not at the moment, I'm afraid. For some use cases, the recomended approach is to start a VM with way-too-much ram, but inflate a big balloon in it. When more memory is required on the VM, set a higher guaranteed level of RAM. Dan. ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [Users] hot add ram to a vm
On 12/09/2013 06:51 PM, Dan Kenigsberg wrote: On Mon, Dec 09, 2013 at 05:27:16PM +0100, Nathanaël Blanchet wrote: Hello, Is hot add ram to a vm is supported by ovirt, or is it planned to be? Not at the moment, I'm afraid. For some use cases, the recomended approach is to start a VM with way-too-much ram, but inflate a big balloon in it. When more memory is required on the VM, set a higher guaranteed level of RAM. Dan. ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users we're working on hot add cpu now. then we'll start looking into hot add ram. may i ask which guest OS are you looking at and the use case you are trying to solve? thanks, Itamar ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Re: [Users] hot add ram to a vm
Le 09/12/2013 19:32, Itamar Heim a écrit : On 12/09/2013 06:51 PM, Dan Kenigsberg wrote: On Mon, Dec 09, 2013 at 05:27:16PM +0100, Nathanaël Blanchet wrote: Hello, Is hot add ram to a vm is supported by ovirt, or is it planned to be? Not at the moment, I'm afraid. For some use cases, the recomended approach is to start a VM with way-too-much ram, but inflate a big balloon in it. When more memory is required on the VM, set a higher guaranteed level of RAM. Dan. ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users we're working on hot add cpu now. then we'll start looking into hot add ram. may i ask which guest OS are you looking at and the use case you are trying to solve? thanks, Itamar We run many centos guests with ton of tomcats on it, and they are in production. Downtime is forbidden but we need more and more RAM because we often add new applications. -- Nathanaël Blanchet Supervision réseau Pôle exploitation et maintenance Département des systèmes d'information 227 avenue Professeur-Jean-Louis-Viala 34193 MONTPELLIER CEDEX 5 Tél. 33 (0)4 67 54 84 55 Fax 33 (0)4 67 54 84 14 blanc...@abes.fr ___ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
