Re: [Engine-devel] [vdsm] RFC: Writeup on VDSM-libstoragemgmt integration

On 2012-6-23 20:40, Itamar Heim wrote: > On 06/23/2012 03:09 AM, Andy Grover wrote: >> On 06/22/2012 04:46 PM, Itamar Heim wrote: >>> On 06/23/2012 02:31 AM, Andy Grover wrote: >>>> On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: >>>>> Also, there is no mention on credentials in any part of the process. >>>>> How does VDSM or the host get access to actually modify the storage >>>>> array? Who holds the creds for that and how? How does the user set >>>>> this up? >>>> >>>> It seems to me more natural to have the oVirt-engine use >>>> libstoragemgmt >>>> directly to allocate and export a volume on the storage array, and >>>> then >>>> pass this info to the vdsm on the node creating the vm. This answers >>>> Saggi's question about creds -- vdsm never needs array modification >>>> creds, it only gets handed the params needed to connect and use the >>>> new >>>> block device (ip, iqn, chap, lun). >>>> >>>> Is this usage model made difficult or impossible by the current >>>> software >>>> architecture? >>> >>> what about live snapshots? >> >> I'm not a virt guy, so extreme handwaving: >> >> vm X uses luns 1& 2 >> >> engine -> vdsm "pause vm X" > > that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM.