TSM will always keep minimum 1 full TSM DB Backup.
You can never delete that volume from Volhist until you have done a new full 
successful backup.

But it is not recommended to only keep 1 full backup, and you can verify that 
you have a DB Backup by run "q volhist"

Best Regards
Christian Svensson

Cell: +46-70-325 1577
E-mail: Christian.Svensson AT cristie DOT se
Skype: cristie.christian.svensson
Supported Platform for CPU2TSM:: 
http://www.cristie.se/cpu2tsm-supported-platforms

________________________________________
Från: Mehdi Salehi [ezzobad AT GOOGLEMAIL DOT COM]
Skickat: den 28 mars 2010 11:44
Till: ADSM-L AT VM.MARIST DOT EDU
Ämne: delete volhist

Hi,
- A TSM server has weekly full and daily incremental database backups.
- All volume history information are accidentally deleted by "delete volhist
type=all todate=today"
- Can TSM admin restore database backups?

Thanks