John Zlatko is right. Since only TSM1 knows what is on the virtual volume, only TSM1 can perform reclamation of the virtual volume.
The TSM designers then had a design choice about how this is acomplished. The obvious way is for reclamation of the virtual volume to be accomplished by mounting the virtual volume to be reclaimed on TSM1 as input, along with a scratch virtual volume for the output. This involves two physical tape mounts on TSM2, but crucially the data would have to pass over the network from TSM2 to TSM1 when it was read and then from TSM1 to TSM2 when it was written. The way it is actually implemented avoids this duplication. TSM uses the fact that the virtual volume is a copy storage pool volume and therefore all the data containted within it will also typically be located on a primary storage pool volume held locally on TSM1. By using this data instead of the data held on the virtual volume, only the writing of the data is performed over the network. So the process has actually been optimised to reduce network utilisation. However, it should be remembered that reclamation of the virtual volume alone is useless without also separately performing reclamtion of the physical volumes on TSM2 in the way that you describe. Going slightly off-topic, it is debatable whether using the primary storage pool volumes as source for the reclamation is optimal in most real-world scenarios. Since the primary storage pool (physical) volumes will typically be co-located and the copy storage pool (virtual) volumes typically won't be, the 50% reduction in network utilisation is more than negated by the increased number of physical tape mounts required. That is to say the mount of a virtual volume as source typically requires only one physical tape mount on the destination server, whereas to mount the physical volumes required from the primary storage pool requires as many tape mounts as there are nodes whose data is contained in the virtual volume (assuming co-location at the node level). Having said that, if there are a large number of virtual volumes to be reclaimed, TSM will optimise the tape mounts from the primary storage pool to ensure each physical volume is only mounted once. With all that said, I've spent five years struggling to get my head round TSM server-to-server comms and now we're just about to rip it out in favour of SAN-based off-siting of data with library-sharing based on Gresham EDT and ACSLS! Neil Schofield Yorkshire Water Services Ltd. Visit our web site to find out about our award winning Cool Schools community campaign at http://www.yorkshirewater.com/yorkshirewater/schools.html The information in this e-mail is confidential and may also be legally privileged. The contents are intended for recipient only and are subject to the legal notice available at http://www.keldagroup.com/email.htm Yorkshire Water Services Limited Registered Office Western House Halifax Road Bradford BD6 2SZ Registered in England and Wales No 2366682