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ME4 Series storage automatically assigns LUN IDs when the LUN is mapped to the Linux host. Assigning specific LUN IDs to volumes is possible but requires un-mapping and re-mapping the volumes manually. In the Map Volume wizard, administrators can explicitly override the LUN IDs.
After scanning and adding the volumes on a Linux host, the volumes can be identified by either their LUN IDs or their SCSI IDs.
The LUN ID information can be found in ME Storage Manager in the Volumes topic. Select the desired volume and click the Maps tab. The LUN column reflects the assigned ID. If the volume belongs to a Volume Group, right-click the group and select View Map Details. See Figure 4.
The LUN ID information in the Map Details window is shown in Figure 5.
On the Linux host, run the lsscsi command to show the volume LUN IDs. The highlighted digits in red correspond to the LUN IDs of the volumes.
[root@r730xd-1 me4_fs]# lsscsi -is|grep ME4
[18:0:4:0] disk DellEMC ME4 G275 /dev/sdl 3600c0ff0003c589f1e4b6b5b01000000 214GB
[18:0:4:1] disk DellEMC ME4 G275 /dev/sdk 3600c0ff0003c589f97596b5b01000000 161GB
[18:0:4:2] disk DellEMC ME4 G275 /dev/sdm 3600c0ff0003c589f98596b5b01000000 161GB
[18:0:5:0] disk DellEMC ME4 G275 /dev/sdd 3600c0ff0003c589f1e4b6b5b01000000 214GB
[18:0:5:1] disk DellEMC ME4 G275 /dev/sdn 3600c0ff0003c589f97596b5b01000000 161GB
[18:0:5:2] disk DellEMC ME4 G275 /dev/sdo 3600c0ff0003c589f98596b5b01000000 161GB
[19:0:4:0] disk DellEMC ME4 G275 /dev/sdi 3600c0ff0003c589f1e4b6b5b01000000 214GB
[19:0:4:1] disk DellEMC ME4 G275 /dev/sdp 3600c0ff0003c589f97596b5b01000000 161GB
[19:0:4:2] disk DellEMC ME4 G275 /dev/sdq 3600c0ff0003c589f98596b5b01000000 161GB
[19:0:5:0] disk DellEMC ME4 G275 /dev/sdj 3600c0ff0003c589f1e4b6b5b01000000 214GB
[19:0:5:1] disk DellEMC ME4 G275 /dev/sdr 3600c0ff0003c589f97596b5b01000000 161GB
[19:0:5:2] disk DellEMC ME4 G275 /dev/sds 3600c0ff0003c589f98596b5b01000000 161GB
Alternatively, using SCSI IDs to identify the volumes is more precise because SCSI IDs are unique on the storage system and on the host, and they will not change. This method reduces the chance of confusion if the LUN IDs are changed unintentionally. It is common to set up persistent device mapping to set the device file names, file ownership, and permission. This can be achieved by creating udev rules that search for specific SCSI IDs, rename device files, and make ownership and permission changes.
To view SCSI IDs, one option is to run the lsscsi command. See the prior example in the section Identify volumes by LUN ids which shows the SCSI IDs highlighted in blue.
Additional options to show SCSI IDs include using the multipath command (if device multipath is enabled), or scsi_id command. These options are detailed as follows:
Option 1: Show the SCSI ID with the multipath command.
# multipath -l mpathb
mpathb (3600c0ff0003c589f1e4b6b5b01000000) dm-6 DellEMC ,ME4
size=200G features='0' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| |- 18:0:5:0 sdd 8:48 active undef unknown
| `- 19:0:5:0 sdj 8:144 active undef unknown
`-+- policy='service-time 0' prio=0 status=enabled
|- 18:0:4:0 sdl 8:176 active undef unknown
`- 19:0:4:0 sdi 8:128 active undef unknown
Option 2: Show the SCSI ID with the scsi_id command.
# ls -1 /dev/sd[a-z] /dev/dm*|while read path
do
(echo $path:; /usr/lib/udev/scsi_id --page=0x83 --whitelisted --device=$path)|xargs -n 2
done
/dev/dm-6: 3600c0ff0003c589f1e4b6b5b01000000
/dev/dm-7: 3600c0ff0003c589f97596b5b01000000
/dev/dm-8: 3600c0ff0003c589f98596b5b01000000
/dev/sdi: 3600c0ff0003c589f1e4b6b5b01000000
/dev/sdj: 3600c0ff0003c589f1e4b6b5b01000000
/dev/sdk: 3600c0ff0003c589f97596b5b01000000
/dev/sdl: 3600c0ff0003c589f1e4b6b5b01000000
/dev/sdm: 3600c0ff0003c589f98596b5b01000000
/dev/sdn: 3600c0ff0003c589f97596b5b01000000
/dev/sdo: 3600c0ff0003c589f98596b5b01000000
/dev/sdp: 3600c0ff0003c589f97596b5b01000000
/dev/sdq: 3600c0ff0003c589f98596b5b01000000
/dev/sdr: 3600c0ff0003c589f97596b5b01000000
/dev/sds: 3600c0ff0003c589f98596b5b01000000
The SCSI IDs of ME4 Series volumes can be retrieved using one of the two following ways:
Option 1: Export the volume information in ME Storage Manager.
In ME Storage Manager in the Volumes topic, select the desired volume or volumes and click the Export to CSV button. Select the data and format in the Export Data to CSV dialog. After the CSV file is created and downloaded to your computer, open the file with a word processor or spreadsheet application. The volume SCSI IDs are listed in the CSV file in the WWN column. See the following figures.
Option 2: Use the following interactive CLI command to identify ME4 Series volume SCSI IDs.
# ssh manage@IP-address
# show volumes details type base pattern r730xd-1-*
Pool Name Total Size Alloc Size Class Serial Number WR Policy Cache Opt Read Ahead Type Tier Affinity Snap-Pool Desc WWN
Large Virtual Extents Role Health Reason Action
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
A r730xd-1-vol0001 200.0GiB 176.0MiB Virtual 00c0ff3c589f00001e4b6b5b01000000 write-back standard Adaptive base No Affinity medium 600C0FF0003C589F1E4B6B5B01000000
Disabled OK
A r730xd-1-vol0002 150.0GiB 124.0MiB Virtual 00c0ff3c589f000097596b5b01000000 write-back standard Adaptive base No Affinity medium 600C0FF0003C589F97596B5B01000000
Disabled OK
A r730xd-1-vol0003 150.0GiB 52.0MiB Virtual 00c0ff3c589f000098596b5b01000000 write-back standard Adaptive base No Affinity medium 600C0FF0003C589F98596B5B01000000
Disabled OK