enabling compression from tape drive

[Ricky_4]

Hi All,

Through the "BEST" device file of the DAT drive, we are able to use the compression features.

But one of the server still could not use compression. Probably, have to enable compression from "72 DAT Drive" of HP.

Anyone knows how to enable compression of DIP switch from the mentioned tape drive?

Regards,

Adriatico

[A. Clay Stephenson · Accepted solution]

It would be more helpful if you could find the exact model number of the drive (72 DAT Drive is not very helpful I'm guessing that you are referring to a StorageWorks DAT 72 (DDS-5). Also, even if your drive is supposed to be able to write 72GB (or whatever) using the right medium, that assumes a 2:1 compression ratio. How much your actual data will compress determines how much can be written to tape.

[Ricky_4]

I am referring to storageworks DDS5 and media used is also DDS5 cartridge. We would like to write ascii file that is almost 50G.

[A. Clay Stephenson]

How much of your 50GB file actually gets written? If its greater than ~36GB then compression is enabled.

[A. Clay Stephenson]

You are using a 170m tape?

[A. Clay Stephenson]

There is a patch that specifically addresses compression on your drive but you didn't bother to identify your OS.

HP-UX 11.0 -> PHKL_29898

HP-UX 11.11 -> PHKL_29899