We just added an IBM 3580 LTO4 drive to our old 810 (V5R4) expecting to get a weekend's worth of backups unattended. It didn't - when I did a DSPTAP to a spoolfile, copied it to a DB file and used SQL to total the KB stored (isn't there a better way?!!) it came to 768 million KB, or 732GB - which isn't even the native capacity. We're using the default setting for compression / compaction to *DEV which was recommended in what small amount of info I could find on the subject. This translates to compaction = yes, compression = no. I found some info this morning that corrected my understanding of compaction, and it looks like what I really need is to use both compaction and compression to venture into the land of more than 800GB on a tape. But I can't find any specific info as to whether our 400 supports hardware compression on this tape drive. Software compression would probably be hopeless.
So long story short - can I specify hardware compression and compaction, and if so, how?