MSL2024 FC drive ports using

[Rafael-Antonio]

Hi,

Please your help, we have a MSL2024 with one drive LTO-5 FC, the drive have two ports A and B, the question is:

Can we use both ports? or we need some kind of license, for example Port A connect to SAN 1 and Port B to SAN 2, both SAN are independently.

Additional, we have the following note in this link:

https://support.hpe.com/hpesc/public/docDisplay?docId=emr_na-c01512219

NOTE: HP recommends that user cable Port A only and that user configure Port B for Auto Detect on Fibre Speed and Port Type.

What is the meaning of this NOTE?

Thank you and regards.

Rafael

[Curtis_Ballard · Accepted solution]

No license is required to use both ports on a Fibre Channel tape drive for an HPE MSL tape library.

There is some software that doesn't understand multiple paths to a tape drive and thinks that two tape drives are connected.  When the software sees two paths and thinks that it has two tape drives then there are lots of conflicts.  The statement about "should only cable port A" was put into the manual due because of customer support calls due to their software presenting more drives than actually existed.

It would be better for the statement to say "If your software supports multiple paths to tape drives then both port A and port B should be connected and they should be connected to different SANs for maximum availability.  If your software does not support multiple paths to tape drives then only port A should be connected."

If you have software that works with multi-path tape drives then go right ahead and attach both FC cables.

Just having two FC cables isn't going to provide full path failover.  If a path fails during operation the backup job will probably fail but the application can reconnect using another path and may have recovery capability.

If you want true path failover where the operations are automatically moved to the second path if the first fails then there is a license required and a special driver for path failover for tape drives.