Hi Dimitris, Thanks for the proposals. Here are my 0.02€ on it:
On Fri, Feb 28, 2014 at 1:41 PM, Dimitris Aragiorgis <[email protected]>wrote: > Hello team, > > I want to add two more features related to KVM; one related to > migration capabilities and one for online disk resize. I would > like to discuss some implementation details before sending any > patch. > > migration caps > -------------- > > KVM supports multiple migration capabilities. The are enforsed > via `migrate_set_capability` monitor command which takes capability and > on/off as arguments. Currently (1.7) kvm has 4 caps: > > MIGRATION_CAPABILITY_X_RDMA_PIN_ALL > MIGRATION_CAPABILITY_AUTO_CONVERGE > MIGRATION_CAPABILITY_ZERO_BLOCKS > MIGRATION_CAPABILITY_XBZRLE > > We have been using xbzrle and auto-converge for a while now. Both > improve migration speed a lot. Still on some cases (Windows 2008r2 + > drbd + xbzrle) cause BSOD on the windows VM. > > So I want to include migration caps in hvparams. The dilema is the > following: > > 1) Introduce *one* hypervisor parameter named `migration_caps` and include > a "something" separated list of enabled caps. For example: > > HT_MIGRATION_CAPS = "xbzrle:-auto-converge" > HT_MIGRATION_CAPS_DELIM = ":-" > I'd go for this solution, but naming the parameter something with KVM, like HV_KVM_MIGRATION_CAPS. > > just like HV_KVM_SPICE_TLS_CIPHERS or > > 2) Introduce multiple hypervisor parameters named: > > migration_cap_auto_converge > migration_cap_auto_xbzrle > .... > > that can take on/off values? > > Ofcourse the best would be to defines a dict as an hvparam which is > currenlty not supported (nor it would be I guess). > > > online disk resize > ------------------ > > On a debian wheezy VM I have tried the following: > > gnt-instance grow-disk debian 0 10G > > and then: > > echo block_resize hotdisk-a37058ee-pci-4 35G | socat - > unix:/var/run/ganeti/kvm-hypervisor/ctrl/debian.monitor > > and inside the VM fdisk -l shows a 35G disk (I think a 3.2 kernel is > needed). > > Hotplug support introduced NIC/Disk identifiers for KVM. So now we are able > to use such a command. > > By the way if you do the resize you cannot shrink it. Plus giving a size > larger than the physical disk results to an error. > > Currently HotplugDevice() regarding disk modifications is not implemented > on > the hypervisor side. We could either use the existing code and extend > HotModDevice() or we could create new RPC/backend/hypervisor methods. > > So, what do you think? > Sounds cool! Thanks, Thomas > > Thanks in advance, > dimara > > > PS: Currently grow-disks takes only disk index as identifier. We should > support name and uuid as well. I will fix that in the online disk resize > patch set. > -- Thomas Thrainer | Software Engineer | [email protected] | Google Germany GmbH Dienerstr. 12 80331 München Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Geschäftsführer: Graham Law, Christine Elizabeth Flores
