Limit of 8 LUNs per SCSI bus

[tlemons]

Hi

I'm an HP-UX newbie. We have a v11.11 system. I've connected (via Fibre Channel) a tape library with 10 tape drives to this system, but (even after an 'ioscan -fnC tape') HP-UX only sees the first 7 tape drives.

Is than well-understood o/s limitation, or something uncommon?

Thanks!
tl

 

[Chacalinc]

do you have the SCSI/LUN ID provided for all the tapes? may be some tapes have the same LUN ID... take a look to the library configuration... HPUX should support the 20 tapes.

FC supports up to 256 devices, SCSI supports up to 16 (0-F, including HBA) SCSI ID and 8 LUN ID (0-7).

 

[Martin999]

SCSI does go up to 16 devices (incl. controller), but not all .. would need wide SCSI.

In nutshell

Fast Narrow / Differencial - uses SCSI ids 0-7, with 7 (normally being controller, therefore 7 devices 0-6).

Stand SCSI - same

Fast/Wide Scsi - 15 devices

Martin

 

[leplatpa]

Hi,
I have the same problem with a HP9000 L2000 HP-UX 11.00. Can somebody tell me how to increase the number of LUN in the system ?

 

[yai]

if the tapes are not connected directly to a san switch, the tape library has to do the scsi-ip mapping. e.g. if the scsi tapes are connected to the san via a crossroads bridge, the bridge maps the scsi-ids of its internal scsi busses to fibre channel bus/target/lun. example (from an old adic library using crossroads bridges):
device FC LUN Bus Target LUN
Tape 1 0x00 0 1 0
Tape 2 0x01 0 2 0
Tape 3 0x02 1 3 0
Tape 4 0x03 1 4 0

 

[Chacalinc]

By the way, do you lnow the scsi id of the 10 tapes? if you are jumping 1 address, there is a posibility that HP stop scanning the bus if one ID is not used, example:

IDs: 0, 1, 2, 3, 4, 8, 9, 10

Note I jump from 4 to 8... In older hp-ux, the OS will scan the bus up to the 4, because as 5 does not exist in the bus, hp will stop scanning the bus and continue with another HBA or SCSI card.

I suggest to see the SCSI ID of all tapes, and let them ordered in continuos IDs.

Cheers.