Linux multipath-tools with EMC CX3-40

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Howto use EMC CX3-40 with Linux multipath-tools #
Running Ubuntu 6.06.1 LTS on an EMC Clariion CX3-40 is actually quite simple. Why EMC Powerpath, if there are also the multipath-tools (*is of course not supported). Here are the necessary configs:
Configuration /etc/multipath.conf #
The blacklist lists all device names that must not be used by multipath, e.g. the internal system discs (/dev/sda … /dev/sdf):
blacklist {
devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
devnode "^hd[a-z][[0-9]*]"
devnode "^sd[a-g][[0-9]*]"
devnode "^hda[0-9]*"
devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
devnode "sd[a-f]$" // internal disks
}
The CX3-40 reports under the name “DGC”:
devices {
device {
vendor "DGC"
product "RAID 5"
path_grouping_policy group_by_prio
prio_callout "/sbin/mpath_prio_emc /dev/%n"
getuid_callout "/lib/udev/scsi_id -g -s /block/%n"
path_checker emc_clariion
features "1 queue_if_no_path"
no_path_retry 300
hardware_handler "1 emc"
failback immediate
product_blacklist "LUNZ"
}
}
multipaths {
# Storage 1, LUN 21
multipath {
wwid 3600601642d93190004d1fe31xxxxxxxxx
alias rr1-lun21
path_grouping_policy failover
failback immediate
}
# Storage 3, LUN 22
multipath {
wwid 3600601642b9319004da05984xxxxxxxx
alias rr3-lun22
path_grouping_policy failover
failback immediate
}
}