Hi, All I have done some work to test the performance of LUN scanning, use "iscsiadm" with "--rescan" like what Nova dose. In my test, a host connected with a lot of LUNs , more than 1000 LUNs. Because "--rescan" will cause kernel to scan all of the LUNs connected to the host, it costs several minutes to complete the scanning.
According to "connect_volume" at line 284 in nova.virt.libvirt.volume.py: https://github.com/openstack/nova/blob/master/nova/virt/libvirt/volume.py#L252 Nova uses "iscsiadm" with "--rescan" to detect new volume, but this command will scan all of the LUNs, including all the others which already connected to this host. So if a host has a large number of LUNs connected to it, the connect_volume will be very slow. I think connect_volume needn't scan all of the LUNs, only need scan the LUN specified by connection_info. Is it necessary to discuss a more efficient way to improve this issues. -- Best wishes ====================== Peter.W ====================== _______________________________________________ OpenStack-dev mailing list OpenStackemail@example.com http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev