On 03/16/2010 10:23 AM, Daniel P. Berrange wrote:
In the context of the RHEV management application, iSCSI/SCSI Fibre are providing the raw storage, with LVM VGs on top and the carving LVs for the guests. In the common case the admin/app would monitor VG usage& LV rate of increase to ensure extra space was available in the VG ahead of it being needed. eg if the VG comes close to exhaustion then further LUNS can be obtained and added as PVs to the LVM volume group. So you can't guarentee that a VM won't stop on ENOSPC, but it is very unlikely if the system is operating correctly. As an added complication, since cluster-LVM isn't used, all LVM operations have to be performed on a dedicated/exclusive storage host and then metadata refreshed/propagated to other hosts running VMs. This last issue implies that letting QEMU resize its LV would never be possible, even if it were not for the permissions problem.
Sounds like a good argument for polling :-) Regards, Anthony Liguori
Regards, Daniel
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