XP12000 CV CLI -- Cannot "create lun" with LUN No. greater than 255 (FF)

[Alzhy]

Has anyone seen this problem yet? I used to be able to prior to our CommandView 2.0 getting re-installed.



CV_CLI 30015 (R/W)> create lun 3b:4b,fhp007b,3f1,0,31

Sending Request to CV server ...


30015 : The server has latest data.

Error: 3f1 The specified LUN id is invalid

CV_CLI 30015 (R/W)> create lun 3b:4b,fhp007b,f1,0,31
Sending Request to CV server …
30015 : The server has latest data.
Create LUN operation is successful.

[ESC Team]

Hello Nelson,

The Commandview XP V2.0 CLI Reference Manual says that the LUN ID parameter of the "create lun" command has a valid value range of 0-255 and must be specified in hex (ie: x'00' to x'FF').

What has led you to believe that LUN values greater than x'FF' are allowed? Commandview XP 1.8 has the same valid value range for this parameter.

Regards, Maurice Clark.

[Alzhy]

Hmm.. I must have been done it via the GUI then. Who knows?

Anyways - if I am going to do presentations with LUN numbers greater than 255 - I have no other option then but to do the GUI? I am sure we will not be alone to have this need but will this ever be fixed/enhanced?

[ESC Team]

Hello Nelson,

I'm not sure...good question though, let me
see if I can find out.

Maurice Clark.

[Vincent Fleming]

Last I saw, the FC/SCSI protocol specification allows only a single byte for LUN number; hence the limitation of 255 LUNs. These standards are very slow to change, because it would cause a change in the size of the data structure sent between the array and the host for every I/O operation.

It would be ugly to change the spec - every vendor would need to change their implementation - OS vendors, switch vendors, array vendors, software vendors, etc.

There are several ways you can circumvent this limitation, though, such as using more ports on the XP and/or more HBAs in your server - you can put 2 HBAs from the same server on the same port (as far as the XP is concerned, diffferent WWN's on the cards make them different - just put them in different host groups.)

So, if you had 4 HBAs in your server, 2 per fabric, you could have 2 HBAs get different sets of LUNs from the same XP port (ie: CL1-A), if you put the 2 HBAs in their own Host Groups.

Cheers,

Vince

[Alzhy]

Vincent.. The XP indeed allows for mapping LDEVs to have LUN numbers greater than 255.. the virtual bus is simply increased every 128 LUNs..

I am just wondering why the GUI will allow this whilst the CV CLI is only restricted to no more than 255.

[Vincent Fleming]

I guess my age is starting to show... ;-)

I found in the docs that the XP itself will present LUNs numbered from 0 to 1023. You are correct.

The limitation you see is no doubt a CLI limitation.

Have you opened a case with Support?