Hi, I struggle to setup multipath devices by dmsetup, multipath-tools and multipathd to get a pure failover path (no traffic sharing). I followed the description at http://christophe.varoqui.free.fr/multipath.html and refered to all I could find on the web, but some questions remain. Maybe you could give some advices? This is the hardware: Host: FSC RX300 (IA32) HBA: 2 x Emulex LightPulse LP9802 Switch: 2 x Brocade 3800 Storage: S80, 2 x Mylex (only failover, no dual write allowed) First, how to get a WWID? I have 4 devices with 2 paths each. `scsidev -s` should provide it but doesn't: # scsidev -s Serial number of /dev/scsi/sgh1-1c0i0l3: "0003cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh1-0c0i0l3: "0003cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh1-1c0i0l2: "0002cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh1-0c0i0l2: "0002cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh1-1c0i0l1: "0001cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh1-0c0i0l1: "0001cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh1-1c0i0l0: "0000cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh1-0c0i0l0: "0000cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh0-0c0i0l3: "0003cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh0-0c0i0l3: "0003cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh0-0c0i0l2: "0002cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh0-0c0i0l2: "0002cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh0-0c0i0l1: "0001cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh0-0c0i0l1: "0001cc7420000080e512cc740000000000000000" HSV OS Id: 0 Serial number of /dev/scsi/sgh0-0c0i0l0: "0000cc7420000080e512cc740000000000000000" Serial number of /dev/scsi/sdh0-0c0i0l0: "0000cc7420000080e512cc740000000000000000" HSV OS Id: 0 So do I need to provide WWIDs for /etc/multipath.conf ? How to identify the devices if for XXX=[a-h]: # /sbin/scsi_id -g -p 0x83 -s /block/sdXXX 220000003390011d3 I.e. all IDs are equal (but configured right, i.e. a=e,b=f,c=g,c=h). Is it wise to take the unique path as ID? : # ls -l /sys/block/sdb/device /sys/block/sdb/device -> ../../devices/pci0000:04/0000:04:08.0/host0/0:0:0:1 The hardware is not listed in setup_default_hwtable and I wonder whether I can define it by multipath.conf at all since sysfs does provide the vendor but NOT the "product": # ls /sys/block/sdb/device/ . .. block delete detach_state device_blocked generic model online power queue_depth rescan rev scsi_level timeout type vendor Instead I could use 'model "FC2502 "' - but that's not implemented. I tried a direct approach by dmsetup, but didn't get a device: # echo "0 274968576 multipath 10 2 1 round-robin 1 0 \ /dev/sdb 1 round-robin 1 0 /dev/sdf" | dmsetup create /dev/dm-0 k_set_name: Device /dev/dm-0 not found Command failed Maybe I am not too familiar with hotplug and udev. I already did add a udev rule: # grep dm /etc/udev/udev.rules KERNEL="dm-[0-9]*", PROGRAM="/sbin/devmap_name %M %m", NAME="%k", SYMLINK="%c" but # /sbin/devmap_name 8 16 No devices found Although the devices exist: brw-rw---- 1 root disk 8, 0 Jun 30 21:04 /dev/sda brw-rw---- 1 root disk 8, 16 Jun 30 21:04 /dev/sdb brw-rw---- 1 root disk 8, 32 Jun 30 21:04 /dev/sdc brw-rw---- 1 root disk 8, 48 Jun 30 21:04 /dev/sdd brw-rw---- 1 root disk 8, 64 Jun 30 21:04 /dev/sde brw-rw---- 1 root disk 8, 80 Jun 30 21:04 /dev/sdf brw-rw---- 1 root disk 8, 96 Jun 30 21:04 /dev/sdg brw-rw---- 1 root disk 8, 112 Jun 30 21:04 /dev/sdh Does this look like some older bugs or do I overlook something important here? Last but not least, I use kernel-smp-2.6.5-7.111 udev-021-36.32 multipath-tools-0.2.1-1.5 from SLES9 and also played around with multipath-tools-0.3.7 from source. So if you have some hints for me that would be great. I would give some feedback and test results and in case of success a small documentation as refund :-) Thanks and kind regards, Andreas