As TSM server is only used as a container, and has no view on what RMAN backup, no versionning is used (retention managed by RMAN) as soon as a file is deleted, it must be removed from TSM

verexist    1
verdeleted  0
retextra    0
retonly     0

http://books.google.lu/books?id=HokwaoWt3-EC&pg=RA1-PA174&lpg=RA1-PA174&dq=policy+tdp+tsm&source=bl&ots=BJEqMB_zvq&sig=OoYDtOV8xXpNLIBM3of2en5-Pvk&hl=en&ei=P8uwSq6GBuSa4gagsoWtCg&sa=X&oi=book_result&ct=result&resnum=2#v=onepage&q=&f=false

When creating management classes for either Exchange legacy backups or VSS backups to TSM, use a timed retention period, rather than number of versions(RETEXTRA/RETONLY options, not VEREXISTS/VERDELETED) to allow the backups to expire based on time.

• Set VEREXISTS and VERDELETED to unlimited so that you will keep as many backups as are created during the required retention period. To keep each backup of this type for at least 30 days, create the management class with these parameters:

– VEREXISTS nolimit
– VERDELETED nolimit
– RETEXTRA 30
– RETONLY 30

• When creating a management class for VSS backups to LOCAL, use the version options in Tivoli Storage Manager (VEREXISTS/VERDELETED), because the number of versions you will keep depends on how much disk you have available for shadow target copy sets.

To keep four versions, (inactive for at least seven days) use these parameters:

– VEREXISTS 4
– VERDELETED 4
– RETEXTRA 7
– RETONLY 7

Note: We have not mentioned the INCREMENTAL, DIFFERENTIAL or DBCOPY backup types, because you should not mix backup types (VSS and legacy) that truncate logs. These options are possible to use but be very careful how you plan this type of backup strategy, as they could interrupt each other’s backup scheme if mixed.

Ref: http://www.redbooks.ibm.com/ sg247373 - Using IBM Tivoli Storage Manager to Back Up Microsoft Exchange with VSS.pdf

For VMware backup, to keep 7 versions of a backup VM, only verexists and retextra are used.
Now using TDP for VE v7, will use verdeleted and retonly when you want to remove a backup VM using command:

dsmc expire <vmname> -objtype= vm

Create for example the management class with these parameters:

– VEREXISTS 7
– VERDELETED 1
– RETEXTRA 30
– RETONLY 30