topic enabling compression from tape drive in Operating System - HP-UX

enabling compression from tape drive

Ricky_4 — Mon, 11 Apr 2005 20:38:46 GMT

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

Re: enabling compression from tape drive

A. Clay Stephenson — Mon, 11 Apr 2005 21:05:15 GMT

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.

Re: enabling compression from tape drive

Ricky_4 — Mon, 11 Apr 2005 22:07:26 GMT

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

Re: enabling compression from tape drive

A. Clay Stephenson — Mon, 11 Apr 2005 22:24:46 GMT

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

Re: enabling compression from tape drive

A. Clay Stephenson — Mon, 11 Apr 2005 22:33:35 GMT

You are using a 170m tape?

Re: enabling compression from tape drive

A. Clay Stephenson — Tue, 12 Apr 2005 10:03:45 GMT

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