Unfortunately what you are trying is not possible. You can not have one
storagepool using two difference device classes. And since two robots can
not be a member of the same deviceclass - you are at a dead-end.

This is the same with TSM.

You need to configure the 2'nd 3995 as a separate storagepool.

If you storagepools look something like this :

DISK_POOL  => 3995_POOL(old)

You might consider doing a new setup like this :

DISK_POOL => 3995_POOL(new)  => 3995_pool(old)

That way all new data will go into the new 3995 pool.

Good luck :-)

Regards,

Jesper Matthiesen
WISEhouse Denmark A/S