Linux Multipath

How to enable multipath between a SLES 10 SP1 and Engenio 6998

Required kernel modules are: dm_multipath, dm_rdac

Software requirement is "multipath-tools"

root@host# cat /etc/multipath.conf

# This is a template multipath-tools configuration file
# Uncomment the lines relevent to your environment
defaults {
        udev_dir                /dev
        polling_interval        10
        selector                "round-robin 0"
        path_grouping_policy    multibus
        getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
        prio_callout            /bin/true
        path_checker            readsector0
        rr_min_io               100
        rr_weight               priorities
        failback                immediate
        no_path_retry           fail
        user_friendly_names     no

# Disable multipath check on local disks
blacklist {
       device {
               vendor SEAGATE
               product ST914602SSUN146G

# Enable RDAC failover for
# ENGENIO disks
# (names taken from /proc/scsi/scsi )
# vendor => vendor
# model => product
devices {
       device {
               vendor                  "ENGENIO"
               product                 "INF-01-00"
               path_grouping_policy failover
               getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
               features "1 queue_if_no_path"
               path_checker rdac
               prio_callout "/sbin/mpath_prio_tpc /dev/%n"
               hardware_handler "1 rdac"
               failback immediate

boot.multipath and multipathd services must be started.