Appendix A Using virtual volumes on a single TSM server

Virtual volumes are perfect for backupsets, because they are created with just the size of the data put into them and they are stored together on physical tapes, so no tape space is wasted. Virtual volumes are normally used with 2 servers, one source and the other the target server, but we have been testing it with one server and it seems to work OK except for a small snag.

The simple setup is as follows:

Define a node of type server under which to store the virtual volumes:
reg no virtnode virtnode t=s maxnummp=6

Define a remote server which in reality is the same server:
def server virtserv hla=127.0.0.1 nodename=virtnode password=virtnode

Define a device class using this server:
def devc virtclas devt=server servername=virtserv mountlimit=6

Now you are ready to generate backupsets that store data in device class virtclas. With this setup, the data is stored in the storagepool pointed to by the default archive copy group of the domain in which virtnode resides.

If you want to direct the data to a special pool not used for archiving you must do it like this:

def dom virtual
def pol virtual virtual
def mg virtual virtual virtual
assign defmg virtual virtual virtual
def co virtual virtual virtual t=a dest=specialpool
act pol virtual virtual
reg no virtnode virtnode t=s maxnummp=6 dom=virtual
def server virtserv hla=127.0.0.1 nodename=virtnode password=virtnode
def devc virtclas devt=server servername=virtserv mountlimit=6

The snags we ran into are that if you do a "delete backupset xxx yyy", the administrator session is hung. This is because there is a session open for virtnode. If you cancel the session for virtnode, then the administrative session is freed and the backupset is actually deleted.

Another snag is that when running multiple backupset generations in parallel, the communication sometimes gets locked up and only a "cancel session" of one of the server to server sessions will make it continue. As it is now, it cannot be recommended for production use, but if Tivoli could fix the hangs, then it would be a superb way of handling backupsets on one server.