configure multipath

[satish]

Dear Erman,

Listing SCSI identifiers

for i in `cat /proc/partitions | awk {'print $4'} |grep sd`; do echo "### $i: `scsi_id -g -u -s /block/$i`"; done
...
### sdh: 360060e80045b2b0000005b2b0000163c
### sdh1:
### sdi: 360060e80045b2b0000005b2b0000163c
### sdi1:
...
### sdk: 360060e80045b2b0000005b2b00001679
### sdk1:
...
### sdm: 360060e80045b2b0000005b2b000006c4
### sdm1:
### sdn: 360060e80045b2b0000005b2b000006d8
### sdn1:
### sdo: 360060e80045b2b0000005b2b00001007
### sd01:
...
### sdz: 360060e80045b2b0000005b2b00001679
### sdz1:



To get WWID of disks

 ll /dev/disk/by-id/
lrwxrwxrwx 1 root root 9 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e -> ../../sda
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part1 -> ../../sda1
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part2 -> ../../sda2
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part3 -> ../../sda3
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part4 -> ../../sda4
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part5 -> ../../sda5
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part6 -> ../../sda6
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-3600508e000000000158d6d2169801c0e-part7 -> ../../sda7
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-360060e80045b2b0000005b2b000006b0 -> ../../sdaa
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-360060e80045b2b0000005b2b000006b0-part1 -> ../../sdl1
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-360060e80045b2b0000005b2b000006c4 -> ../../sdab
lrwxrwxrwx 1 root root 11 Jun 27 07:17 scsi-360060e80045b2b0000005b2b000006c4-part1 -> ../../sdab1
lrwxrwxrwx 1 root root 9 Jun 27 07:17 scsi-360060e80045b2b0000005b2b000006d8 -> ../../sdn
lrwxrwxrwx 1 root root 10 Jun 27 07:17 scsi-360060e80045b2b0000005b2b000006d8-part1 -> ../../sdn1

could you please let us know what will the difference between scscid and wwid.We are confused which one of the above whether scsci id's or wwid's to configure in multipath.conf

Thank you

[ErmanArslansOracleBlog]

The Id that is returned from scsi_id is the SCSI device WWID. It is unique..

The files (links) that are present in /dev/disk/by_id is created by UDEV.. Again unique.. It is a product of persisting naming methods in Linux.

Linux Native Multipathing (MPIO) uses the SCSI device WWID.

So if you are building a multipath conf, then you ll proceed with the SCSI WWID.