what backup are you doing? image or data or??
if you do for data, and you cannot wait so long, then do real time replication to another hdd then only move to tape later..it also depends a lot on read write speed so many factors need to be considered
REGISTER or login:
DSPLOG PERIOD((*AVAIL *CURRENT) (*AVAIL *CURRENT)) +
OUTPUT(*PRINT) MSGID(CPC3701 CPF3771) /* +
Libary save and not saved messages */