topic Re: ESL9000 tape drive problem in Operating System - OpenVMS

ESL9000 tape drive problem

James Viswasam — Tue, 16 Sep 2008 03:34:05 GMT

We are using 16 SDLT320 drives attached through NSR. We use MDMS and ABS for managing backup.
During the backup , the drives seemingly go offline due path disconnects and have to abort the batch job that runs the backup and restart.

1. The batch job issues a mount request for second volume
2. I mount a free volume through MDMS and reply to the request with mounted
3. Job keeps repeating the request
4. Log file says "medium is offline " When I check the drive, it shows disconnected paths
Questions :
What am I doing wrong ?
Is it possible to set the path and not use multipath

We are on VMS 8.3 on GS1280.

Please see the attached text file.

Re: ESL9000 tape drive problem

Wim Van den Wyngaert — Tue, 16 Sep 2008 05:44:54 GMT

I know nothing but found this in the 8.2 notes. Is your tape drive mscp served ?

failover between direct and MSCP-served paths is not supported for tape devices (unlike multipath failover between direct and MSCP-served paths for SCSI and Fibre Channel disks introduced in this release).

fwiw

Wim

Re: ESL9000 tape drive problem

Wim Van den Wyngaert — Tue, 16 Sep 2008 10:06:53 GMT

Ignore that post. You don't have mscp.

http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00775232/c00775232.pdf
says that ETLA drives don't support mult-path failover (search for etla). That's in contrast with all docs saying that VMS can handle it starting from 7.3-1.

Confusing

Wim

Re: ESL9000 tape drive problem

James Viswasam — Tue, 23 Sep 2008 18:36:24 GMT

I am thinking of forcing the tape drive to use only one path by issuing the following command
set device/noenable/path=xyz device:

Would this work for tape device ? Are there any other issues that may crop up. Perhaps I can set this before starting the backup and then enable it after the backup is completed.

( from VMS help )
SET

DEVICE

/ENABLE

/ENABLE
/NOENABLE

Enables or disables a path to a multipath device; the affected
path is the one named in the /PATH qualifier. All paths are
initially enabled; the current path cannot be disabled.

Re: ESL9000 tape drive problem

Rob Leadbeater — Tue, 23 Sep 2008 19:10:04 GMT

Hi James,

Is it possible that there are other hosts on the SAN that are accessing the library, which could be causing VMS to confused ??

Cheers,

Rob