Hi Allen,

> I think you are not considering what a 'tape library manager' does in
> the TSM world.  The behavior you discuss is not likely to be useful in
> the case the Original Poster was describing.
>
> The key advantage to IRMM is that it presents varying resources in a
> seamless manner.  In the dual-data-center configuration the OP
> described, I think it would not be useful or desirable to access the
> 'local' and 'remote' drives interchangably.  In his place, I'd want
> that separation clear and clean

TSM Library Manager meets the tape management and tape sharing requirements
of most TSM customers. However, in some situations additional software like
IRMM can help to fulfil and automate advanced requirements.

Regarding the dual data center I agree that you want to have clear control
in which data center your data is written to store the data of primary
storage pool and backup storage pool in different locations. TSM Library
Manager as well as IRMM can enforce this requirement.

However, what are the requirements during an outage where one library or a
whole data center is not available? Some customers just stop to create
copies or increase the TSM disk storage pool. Other customers prefer to
redirect the data to tape in the "wrong" data center and move it afterwards
to the desired location: It is better to have the data temporarily in the
wrong location than having no copy at all. For some customers it is OK to
reconfigure TSM to redirect incoming data; other customers prefer to
automate the redirection with a tool like IRMM. One of my customers has two
tape libraries in each data center to have both, control about the location
of data and high available tape resources. I understand that this is
overkill for other customers.

IRMM has a lot of other advantages which can be considered as "key
advantage". In the context of dual data centers I would like to mention
that IRMM eliminates the need for defining tape paths in TSM. Consider a
scenario with one TSM Library Manager in each data center, each providing
forty drives to several TSM servers and TSM storage agents: IRMM reduces
the amount of TSM tape paths to zero, detects all tape hardware changes
automatically, provisions tape device handles and scratch volumes during
mount processing to TSM, and provides policy-based fail-over as described
above. This significantly reduces the complexity of tape management for
clustered TSM servers which are protected by HACMP, MSCS, TSA or any other
cluster software.


> Furthermore, I don't anticipate it would be worth learning Z-series
> hardware and software in order to get access to multiple tape
> libraries from one system.  TSM can do that already.
>
> And TSM V6 doesn't run on Z-series.

Both TSM V6 and IRMM are available for Linux on System z. And both can
manage tape resources for Linux, AIX, Solaris, HP-UX and Windows. Depending
on the preferences you can go with TSM Library Manager or with IRMM.

Best regards,
Ulf.

--
Consulting IT Specialist
Author "Storage Networks Explained"

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