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Tape drives limitation on Hp-ux v3

shabash
Frequent Advisor

Tape drives limitation on Hp-ux v3

i have VLS9000 configured with 11 drives.Also One MSL2024 with 1 tape drive.

But Os only show 8 drives.Not able to see rest of tapes.

On Backup application i.e DP i am able to c all tapes.

Is there any parameter which need to change in order to c all rest of tapes.

Anyone??
4 REPLIES
shabash
Frequent Advisor

Re: Tape drives limitation on Hp-ux v3

0/7/1/0/4/0.1.10.255.0.0.0 tape HP Ultrium 3-SCSI
0/7/1/0/4/0.1.10.255.0.0.1 autoch HP MSL G3 Series
0/7/1/0/4/0.1.13.255.0 ext_bus FCP Device Interface
0/7/1/0/4/0.1.13.255.0.0 target
0/7/1/0/4/0.1.13.255.0.0.0 autoch HP ESL E-Series
0/7/1/0/4/0.1.13.255.0.0.1 tape HP Ultrium 3-SCSI
0/7/1/0/4/0.1.13.255.0.0.2 tape HP Ultrium 3-SCSI
0/7/1/0/4/0.1.13.255.0.0.3 tape HP Ultrium 3-SCSI
0/7/1/0/4/0.1.13.255.0.0.4 tape HP Ultrium 3-SCSI
0/7/1/0/4/0.1.13.255.0.0.5 autoch HP Ultrium 3-SCSI
0/7/1/0/4/0.1.13.255.0.0.6 tape HP Ultrium 3-SCSI
0/7/1/0/4/0.1.13.255.0.0.7 tape HP Ultrium 3-SCSI
Ganz
Trusted Contributor

Re: Tape drives limitation on Hp-ux v3

Hello Shabash,

Cannot create legacy DSFs for LUN IDs above 7; use persistent device special files instead .

Reasoning behind the 8 LUN limit : HP-UX 11i v3 introduces a new agile addressing scheme for mass storage devices, with opaque minor numbers, persistent device special files (DSFs), and new hardware path types and formats. The addressing scheme used in previous HP-UX releases, will co-exist with this new scheme to ensure backward compatibility and is referred to as legacy addressing. The legacy addressing will be deprecated in a future HP-UX release. In the legacy addressing scheme, each device path is represented by a minor number, a legacy DSF and a legacy hardware path. The minor number directly encodes SCSI-2 addressing information (SCSI bus, target address and logical unit number), and device options (disk partition number, tape density, etc.). The legacy DSF name also embeds SCSI-2 addressing information. This has the following limitations:

A device with multiple paths is represented by several legacy device special files. Applications and upper layer modules (File system, volume manager, etc.) have to use independent methods such as writing meta data on the device to be able to determine that different legacy DSFs correspond to the same device.

Limited scalability: legacy limits of 256 SCSI bus instances, 16 target identifiers per bus instance and 8 logical unit numbers per target identifier. The use of 15 bits to encode the minor number limits the overall number of lunpaths to 32768.



Workaround :: Upgrade to 11.31 and then change the value of the parameter mentioned below :: (Increase the number of LUNs per bus on the HP-UX server by entering:)

# scsimgr set_attr -a max_lunid=32

OR

Limit the the number of devices presented to the hostport to 8 per port.
shabash
Frequent Advisor

Re: Tape drives limitation on Hp-ux v3

The OS version is Hpux v3.

Will changing the paramter solve the problem??

drives presented to all host using switch zoning.
Ganz
Trusted Contributor

Re: Tape drives limitation on Hp-ux v3

Hi Shabash,

Changing the parameter should help you enable HPUX see more luns than the default 8 luns.