Compression less than 1:1?

[CBT_Help_Desk]

I just saw one of my tapes had a compression ratio of 0.954:1. This isn't a major concern (right now anyway), but does anyone know how a compression of LESS than 1:1 could be achieved?

I just can't think of any reason WHY or HOW it could happen. Does Backup Exec actually DEcompress data somehow?

I haven't checked to see what is on the tape, and the backups are configured for Hardware otherwise none. But that shouldn't even matter. I should be getting a compression ratio of AT LEAST 1:1 no matter what shouldn't I?

[Thomas_Cupps]

join the club. do a search on compression & you'll see that this is a common problem with be10. What OS & SP are you on? What kind of tapes? Tape drive? What kind of data? Remote selections?

[CBT_Help_Desk]

I've been keeping an eye on them. That's what made me take a look to see what kind of compression I was getting.

I'm using win2k3 server BE 10 5520 SP1. Sony LIB-162 sixteen tape library with two Sony SDX-700C tape drives utilizing 100/250 GB Sony AIT-3 tapes. I have 3 server/library setup's that are identical and a couple other Sony external drives through my organization.

I'm really suprised at the fact I get less than 1:1 compression. I should just go back to the good old days of DOS and XCOPY everything. I'd have more space left over at the end of the day. :)

[ray_littlefie1]

Yes there are some issues with BE10 with certain tape drives (IBM LTO's for sure) not actually enabling hardware compression- and hopefully this will be corrected soon.

But to answer you question in a generic fashion- It is possble to get less than 1:1 compression if the tape has many bad blocks (review read/write statistics), or if the data being backed up is already compressed (zip files, jpg's etc). These conditions would be fairly easy to isolate and identify.

[CBT_Help_Desk]

I understand. It's possibel that there are some compressed files that are being backed up. I think the tapes are good though.

For the most part I get pretty good compression. Only on occasion do I get lower than 1:1.

Thank you for answering my question. :)