MSL4048 Can't use both drives at same time

[jacksbox]

Hello,

I'm having an issue with our MSL4048 where I'm unable to write to both HP Ultrium LTO3 drives at the same time.

This is verified with HP Library and Tape Tools when I load media into each drive, go to the Test area, select both drives and perform a Read/Write Test.
The first drive will begin writing tape (whichever drive starts first), but when the second drive starts writing the first one will stop and only the second one will continue writing.

This happens both ways, whether 'Drive 1' or 'Drive 2' starts first, it is the second drive to begin writing that will be successful.

Any ideas out there?

Thank you!

[thomasr]

L&TT may be single-threaded when running tape tests; I don't know for certain.

Tell me a bit more about your environment: Are your drives Fibre Channel, SCSI, or SAS-connect? What backup application and version are you running? Are both drives connected to the same server, or are they connected to different servers? What OS and version are you running under? How do you have your backup job(s) configured? What version of firmware is running on the library?

I know, for instance, that Data Protector can easily do this, either in two separate jobs, or one job with both drives as targets and two backup sources identified. But what you can do depends to a large part on the backup application.

[jacksbox]

Thanks for the reply thomasr.

To answer your questions, the drives are SAS, connected to the same server (HP DL380) running Windows 2003 SP2.
The library is running firmware 6.80 (latest), and the drives are running C24W (latest).

We are using a backup solution called i365 EVault, which uses the RSM (Removable Storage) API in Windows for tape backups.
It is primarily a disk-to-disk solution, but we use the tape backup functions (unfortunately based on RSM) as a secondary backup measure.

[thomasr]

I trust that you will not be overly shocked if I tell you that I am not at all familiar with EVault?

If you have recovered and are sitting down now, we can proceed.

I don't know how to make it work in EVault. I would suggest you consult with their support organization to see if the application can work with libraries, and if the MSL is on the supported list. Some low-end applications do not have the code necessary to support multi-drive targets like a 2-drive MSL.

If EVault support does not have a solution, or the MSL is just not supported, I think you're probably still in luck with a workaround.

In the GUI of the MSL library, you can partition it in to two libraries. Each will have one tape drive and one magazine (the mail slot, if enabled, can be used by either partition). Each partition will show up in Windows Device Mangler as a separate library.

Once the library is partitioned, re-discover it, and send half of your backup jobs to each library. Both should operate at the same time and independently of each other, with only short and rare delays when both libraries would need access to the robot at once.

Please let us know if, and how well, this works!

In the future, it is a good idea to check to make sure your application supports your backup device.

Two good resources from HP are the HP Enterprise Backup Solution Compatibility Matrix (available from www.hp.com/go/ebs ) which is a 44-page matrix of all supported versions of application, tape device, HBA, and OS, including firmware levels and OS patches (and supporting IBM and Sun servers as well). If your environment is not that complex, www.hp.com/go/connect tells the basics of compatibility and support for direct-connect devices (which HBA in which server with which devices).

[jacksbox]

Yeah, EVault's not hugely well-known. I get your reaction quite often :)
Well, maybe not your exact reaction.

The response I get from them is "if RSM supports it, we support it". Not overly helpful.
In any case, all of this was in place before my time, so I'll have to do my best to get it functional.

Thank you for the suggestion, I'll probably give it a shot either tomorrow or Wednesday (when I have some free tapes to play with).
It's a pretty interesting solution to the problem, and will hopefully bypass my problem.

I'll let you know how it goes.

[Curtis Ballard]

Your problem doesn't sound firmware related - more like drive/app conflict, but there is new firmware for that drive which has just released and is highly recommended for SAS drives since it resolves an issue that has caused some command timeouts. The following link should take you to the bundle that has C25W.

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=us&prodTypeId=12169&prodSeriesId=3936307&swItem=co-38806-26&prodNameId=3372100&swEnvOID=1060&swLang=13&taskId=135&mode=4&idx=0

[jacksbox]

Thank you Curtis, I'll be trying that firmware out today.

Thomas, unfortunately it looks like I'm unable to split the library into 2 logical ones.
On the Configuration -> System page, that dropdown list only has one item in it "One Logical Library".
I looked everywhere for some hints as to why this could be, and I tried playing with some settings, but I couldn't get it to offer splitting the library.

Any ideas?

Thanks again.

[Curtis Ballard]

You hit one of the sneaky partitioning behaviors. There is a hardware limitation that drives in the top half of the library control one partition and drives in the bottom half control another partition. If you have two drives but they are both half height drives in the lower half of a 4048, then it isn't possible to partition the library. You have to move one of the drives up a slot and move the blanking plate from that slot down then you can partition.

That is in the documentation but that is always the last place I look.

[jacksbox]

Thanks again Curtis.
I've just updated the library/drive firmware from the link you suggested.
Going to run some tests before proceeding with troubleshooting.

As for the drive placement affecting partitioning, I couldn't find this info in 2 different versions of the user guide that we have stored over here.
Would you happen to have a link to the document you found that in?
It might come in handy for future reference :)

[Curtis Ballard · Accepted solution]

I have discovered that I'm guilty of using a draft copy of the documentation which is not yet published to the web. Sorry about that. The section I was referring to will be in a release of the Addendum to the user guide which will publish in the next few weeks sometime.

The current version of the Addendum is incorrect and implies that two tape drives in the bottom two slots can be partitioned.