AskDba.org Weblog

I am creating 11gR2 RAC setup for one of my client. Following Oracle documentation for storage, I opted for Oracle ASM and asked storage team for new physical devices.
Storage admin thus provided me with a set of LUNs instead of actual physical device names like /dev/sdcxxx.

Now the major task is to get the actual device name associated with LUNs.
In OEL4 this is easy to get by issuing

# iscsi-ls -l
This command will give output like:

DEVICE DETAILS:
---------------
LUN ID : 0
Vendor: DELL     Model: MD3000i          Rev: 0670
Type:   Direct-Access                    ANSI SCSI revision: 05
page83 type3: 6001e4f0003fa9970000083c48573c94
page80: 383438303045500a
Device: /dev/sdh
LUN ID : 1
Vendor: DELL     Model: MD3000i          Rev: 0670
Type:   Direct-Access                    ANSI SCSI revision: 05
page83 type3: 6001e4f0003fbc5b000008dd486dae67
page80: 383438303045500a
Device: /dev/sdl
LUN ID : 2
Vendor: DELL     Model: MD3000i          Rev: 0670
Type:   Direct-Access                    ANSI SCSI revision: 05
page83 type3: 6001e4f0003fbc5b0000082048574033
page80: 383438303045500a
Device: /dev/sdp

But this command is obsolete in OEL5. The replacement for iscsi-ls in OEL5 is iscsiadm.

In OEL5, there are two ways to get the device name associated with LUN:

1. Use iscsiadm -m host -P 4

# iscsiadm -m host -P 4

It will show the output as:

************************
Attached SCSI devices:
************************
scsi6 Channel 00 Id 0 Lun: 0
Attached scsi disk sdk          State: running
scsi6 Channel 00 Id 0 Lun: 1
Attached scsi disk sdm          State: running
scsi6 Channel 00 Id 0 Lun: 10
Attached scsi disk sdah         State: running
scsi6 Channel 00 Id 0 Lun: 11
Attached scsi disk sdai         State: running
scsi6 Channel 00 Id 0 Lun: 13
Attached scsi disk sdap         State: running
scsi6 Channel 00 Id 0 Lun: 14
Attached scsi disk sdaq         State: running

2. Install the OEL5 package: lsscsi-0.17-3.el5 (or similar version).

# lsscsi -l

It will show the output as:

[6:0:0:22]   disk    DELL     MD3000i          0670  /dev/sdbp
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=60
[6:0:0:24]   disk    DELL     MD3000i          0670  /dev/sdbq
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=30
[6:0:0:31]   disk    DELL     Universal Xport  0670  /dev/sdbx
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=60
[6:0:0:32]   disk    DELL     MD3000i          0670  /dev/sdby
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=30
[6:0:0:33]   disk    DELL     MD3000i          0670  /dev/sdcg
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=60
[6:0:0:71]   disk    DELL     MD3000i          0670  /dev/sdch
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=60
[6:0:0:72]   disk    DELL     MD3000i          0670  /dev/sdci
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=30
[6:0:0:73]   disk    DELL     MD3000i          0670  /dev/sdck
state=running queue_depth=32 scsi_level=6 type=0 device_blocked=0 timeout=60

Here we can see the LUN numbers in begning:

[6:0:0:73] i.e 73 is the LUN number here.

[6:0:0:72] i.e 72 is the LUN number here.

Finally I created the disks with correct device names.

Cheers!!!

Saurabh Sood

Written by Saurabh Sood

Visit Saurabh Sood's Website