There are additional considerations when using sp_volchanged.
(UNIX) The Backup Server sends messages to the client that initiated the dump or load request. Use the with notify = operator_console option of the dump or load command to route messages to the terminal where the Backup Server was started.
After mounting another volume, the operator executes sp_volchanged from any SAP ASE server that can communicate with the Backup Server performing the dump or load. The operator does not have to log into the SAP ASE server on which the dump or load originated.
dump database, dump transaction, load database, load transaction in Reference Manual: Commands
isql in the Utility Guide