UUID

 
krsukuma
Frequent Advisor

UUID

Hi,

I can understand UUID is Universally Unique Identifier. Before expanding a new lun we need to get the UUID for the disk.
how to get the disk UUID from windows server and Unix server.
5 REPLIES 5
Sivakumar MJ._1
Respected Contributor

Re: UUID

For Disk expansion you require the WWNID.

For HPUNIX..

# evainfo
usage: evainfo [-a|-d ] [-l] [-f fmt][-u KB|MB|GB][-w [-W][-g
]
-a : Display information for all EVA Luns presented to this host.
-d : Display information for the specified EVA Lun.
-l : Display information in long/full format.
-v : Display EVAInfo tool version details.
-f : Specify output format. The supported values for are:
tab (default)
csv
-u : Specify output format for Capacity {KB|MB|GB}, default is MB.
-W : Collate output based on WWN of Luns.
-w : Display information for the specified Lun WWN.
-g : Use SCSI generic (sg) interface on Linux.
-h : Help


Example output from evainfo -a
Devicefile Array WWNN Capacity Controller/Port/Mode
/dev/rdsk/c4t0d2 5000-1FE1-5007-30F0 6005-08B4-0010-6B67-0000-4000-0083-0000 36864MB Ctl-A/FP-2/NonOptimized
/dev/rdsk/c6t0d1 5000-1FE1-5007-30F0 6005-08B4-0010-6B67-0000-4000-007E-0000 36864MB Ctl-B/FP-2/NonOptimized
/dev/rdsk/c4t0d3 5000-1FE1-5007-30F0 6005-08B4-0010-6B67-0000-4000-008C-0000 36864MB Ctl-A/FP-2/Optimized
/dev/rdsk/c4t0d4 5000-1FE1-5007-30F0 6005-08B4-0010-6B67-0000-4000-0092-0000 36864MB Ctl-A/FP-2/Optimized


For Windows you donot have evainfo..

In Windows based on the Size of Disk and LUN Number you can find which drive to expand.
Sivakumar MJ._1
Respected Contributor

Re: UUID

FYI...

All OS communicates to the SCSI LUN 'number' to a virtual disk, because this is the only addressable entity.

A 64-bit WWN is a characteristic of a Fibre Channel port as a 128-bit LUN-WWN is a characteristic of a virtual disk's LUN mapping, but they cannot be used as direct addresses.

The N_Port ID (Fibre Channel address) is 24 bits and is something different than a 64-/128-bit WWN. It is used to access physical ports in a Fibre Channel fabric and works (a bit) like an IP-address while a 64-bit WWN works (a bit) like a MAC address. A SCSI target address is mapped to an N_Port ID by the operating system device driver.


A UUID is used to persistently identify an object (disk drive, controller, host, vdisk, ...) _within_ an EVA and does not change.

NOTE: By default, the LUN WWN has the same value as the UUID, but it can be changed it if the VDisk is not presented to a host.
Sivakumar MJ._1
Respected Contributor

Re: UUID

Are you using MPIO DSM for HP EVA's in your windows..

What version you use MPIO DSM....
Uwe Zessin
Honored Contributor

Re: UUID

... and here is (one of?) the original thread(s) that Sivakumar MJ. seems to have cut&paste from:

http://forums.itrc.hp.com/service/forums/questionanswer.do?&threadId=1239552
.
Sivakumar MJ._1
Respected Contributor

Re: UUID

Yes, most of the details are available in the forum...