Multipathing and persistent device names

Latest response

I was in the process of adding 4 additional luns to a system whereby I have configured 4 paths to my storage.

I rescanned the SCSI interconnect to add the disks to the system, I then ran lsblk to confirm all of the new device ids could be seen successfully:

sddi 61:0 0 10G 0 disk
sddj 61:16 0 42G 0 disk
sddk 61:32 0 30G 0 disk
sddl 61:48 0 12G 0 disk
sddm 61:64 0 10G 0 disk
sddn 61:12 0 42G 0 disk
sddo 61:96 0 30G 0 disk
sddp 61:112 0 12G 0 disk
sddq 61:128 0 10G 0 disk
sddr 61:144 0 42G 0 disk
sdds 61:130 0 30G 0 disk
sddt 61:176 0 12G 0 disk
sddu 61:192 0 10G 0 disk
sddv 61:208 0 42G 0 disk
sddw 61:224 0 30G 0 disk
sddx 61:42 0 12G 0 disk

I get 4 device entires for each indivdiual device, due to the 4 paths to each device.

I then tried to obtain the WWID of the disk devices in order to do my multipath configuration:

ls -lrt /dev/disk/by-id
scsi-360002af1111110001a003be300009b21 -> ../../sdds
scsi-360002af1111110001a003be200009b21 -> ../../sddv
wwn-0x60002af1111110001a003be300009b21 -> ../../sdds
wwn-0x60002af1111110001a003be200009b21 -> ../../sddv
scsi-360002af1111110001a003be400009b21 -> ../../sddx
wwn-0x60002af1111110001a003be400009b21 -> ../../sddx
scsi-360002af1111110001a003be000009b21 -> ../../sddu
wwn-0x60002af1111110001a003be000009b21 -> ../../sddu

Can anyone tell me why the persistant device name only references a single disk device? Does multipath change this mapping each time an alternative path to the device is used?

Many thanks,

James

ja

Responses