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Hardware comression to 80GB on DLT 4000D

Frequent Advisor

Hardware comression to 80GB on DLT 4000D


We have a DLT4000D tape Drive backup and our database exceeding 40Gb. We would like to perform Hardware compression.
1.How can we perform Hardware compression on this drive?
2.What do density override, 2.6, 6.0, 10.0 and 20.0 Indicators mean?

With Best Regards,
harry d brown jr
Honored Contributor

Re: Hardware comression to 80GB on DLT 4000D


What operating system are you using?

A note on tape densities: if a drive is rated at 40GB, that does NOT mean it can hold 40GB worth of data - it means it can ONLY HOLD 20GB. The 40GB rating means that if you have data that can be compressed to at least a 50%, which is 20GB, then you will only use one tape. This IS WITH HARDWARE compression. Unfortunately, some databases do NOT compress well, especially not at 50%. Things like ascii text files will compress well, sometimes at over 70%. Binary files, like programs, will ACTUALLY TAKE UP MORE ROOM on tape, sometimes at 105% or more.

What you need is an 80GB DLT, or live with the fact that you need to use more than one tape for backups!

live free or die
Live Free or Die
Vincent Farrugia
Honored Contributor

Re: Hardware comression to 80GB on DLT 4000D


Unfortunately it is very difficult for a DLT4000 to hold 80Gb worth of data. As Harry said, that drive can hold 20Gb of uncompressed data, 40Gb compressed. This, of course, assuming a 2:1 compression ratio, which you won't get with many types of databases.

You can to buy a DLT8000 drive in order to do that. This holds 40Gb uncompressed, 80Gb compressed if we assume 2:1 compression. Seeing you have slightly more data than 40Gb, this is a good deal.

Tape Drives RULE!!!