On 31/05/2007, at 3:38 AM, Chris McKay wrote:

Hi all,

I have been told by IBM that fibre LTO2 drives are no longer
available. We
wish to expand the number of drives in our 3584 library from 2 to
5. The
current 2 drives are fibre LTO2 drives, would it pose a problem by
adding
an additional 3 LTO3 drives to that logical library? Is it possible
under
Windows??  I realize I will need to continue to use LTO2 media, as the
existing LTO2 drives would not be compatable with LTO3 media. Our TSM
server is running on Windows 2003.

Compatibility with LTO media is straightforward: one generation back
for write; two generations back for read. So an LTO3 drive is a
perfectly reasonable way to extend your LTO2 capabilities, as well as
giving you the ability to migrate to LTO3 down the road.

At Monash, we're running one silo on LTO3, one on LTO2. We're looking
at upgrading the LTO2 silo to LTO4, and have checked the
compatibility; our information is that TSM is smart enough to mount
LTO media only in drives appropriate to the operation (so LTO2 media
will only mount in an LTO4 drive if it's being read, not written;
LTO4 media will never be mounted in an LTO2 drive; etc.) So if you
were to add LTO3 media to that library down the road, TSM would
access it only through the LTO3 drives (and if all the LTO3 drives
were being used with LTO2 media while an LTO2 drive sits idle, too
bad.) You may want to double check this, though, if it's a concern
for you down the road.

I can't speak for how far this advice extends into Windows - we're
running TSM on Solaris - but it's a starting point. My expectation
would be that there would be no problem as long as the LTO3 drive is
compatible with the drivers on the Windows system.