iSCSI Multipath

• Openstack Nova provides the ability to use iSCSI Multipath. To enable Multipath you need to add following line into nova.conf in the [libvirt] section:

[libvirt]
iscsi_use_multipath = True

For this change to take place you need to restart nova-compute service: $ sudo service restart nova-compute

• Recommended settings for Linux multipath, configuration file /etc/multipath.conf:

devices {
    device {
        vendor "NEXENTA"
        product "COMSTAR"
        path_grouping_policy group_by_serial
        getuid_callout "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
        path_selector "queue-length 0"
        path_checker tur 
        checker tur
        features "0"
        hardware_handler "0"
        prio const
        no_path_retry queue
        rr_min_io 128
    }
}