Re: [libvirt] [RFC 5/5]: Rewrite findLuns function

Daniel P. Berrange wrote: >> # cat /sys/bus/scsi/devices/3:0:0:0/model >> >> and >> >> # cat /sys/bus/scsi/devices/3:0:0:0/type >> >> from both your netapp target and your sun target? Here, at least, for our >> "control" LUN, model returns "Controller" while for the real LUNs model returns >> "VIRTUAL-DISK", so I'm hoping I can distinguish somehow based on what is in >> model, and if not that, based on type. > > Can't you distinguish based on the fact that there'll be no /dev/sdNN > node for it ? Unfortunately, no. The /sys/bus/scsi/devices/3:0:0:0/block:sda (or block/sda) link will only exist once udev has finished plugging the device in. So we have to loop waiting for that to appear. In the case of a control LUN, that will never appear, so we will wait 5 seconds (the current default) to see it appear, and then when it doesn't, we won't know how to distinguish the error case from the control LUN case. I guess we could just not throw an error if we never see a block device, but we would still delay the libvirtd daemon (and the client) unnecessarily.