[David] Couple of questions around memory - as you note XenServer free doesn't have support for memory snapshots - does that increase the number of code paths for this feature? [/David]
Yes, but not much, just call different XAPIs depending on if it's a memory snapshot, either vm.snapshotAsync or vm.checkpointAsync. [David] Also - I imagine snapshotting memory is dramatically more intensive from a diskio perspective. (so a machine with 64GB of RAM now has a 64GB write job) - many moons ago, we specifically modified qemu to not do that because of the performance impact. Any idea what the impact is? [/David] Thanks for the reminder, I haven’t tested the performance, simple functional tests are based on 512M/2G memory VM. It's no good if it will impact other guest VMs on the same host. -Mice -----Original Message----- From: David Nalley [mailto:[email protected]] Sent: Saturday, December 15, 2012 1:19 AM To: [email protected] Subject: Re: [ACS41] VM Snapshot and possibility to introduce it in 4.1 On Fri, Dec 14, 2012 at 7:27 AM, Mice Xia <[email protected]> wrote: > Hi, folks, > > I’d like to discuss the possibility of introducing feature VM Snapshot in CS > version 4.1 and I need some inputs/ideas for the rest of work. > > The background/spec/design is in > https://cwiki.apache.org/confluence/display/CLOUDSTACK/VM+Snapshots. > The implementation is very straightforward (with KISS principle) , codes are > in branch vm-snapshot, based on 4.0.0. > Wow the spec looks good. Couple of questions around memory - as you note XenServer free doesn't have support for memory snapshots - does that increase the number of code paths for this feature? Also - I imagine snapshotting memory is dramatically more intensive from a diskio perspective. (so a machine with 64GB of RAM now has a 64GB write job) - many moons ago, we specifically modified qemu to not do that because of the performance impact. Any idea what the impact is? --David
