topic DLT 8000 in Automated Backup

DLT 8000

CA879156 — Fri, 29 Nov 2002 04:30:51 GMT

DEAR All,
I use the ARCServerIT 6.5 with the HP DLT8000, but the software can't perform the compression, it ask me that it is impossible to do the compression because the Hardware compress is enable,

May I know that is it possible to disable the hardware compress.

Re: DLT 8000

BR19682 — Fri, 29 Nov 2002 06:17:09 GMT

Hi there.
Use the hardware compression. This will take a lot of load off your cpu.
Rgds
Alexander M. Ermes

Re: DLT 8000

Eugeny Brychkov — Fri, 29 Nov 2002 07:39:34 GMT

Alexander is absolutely right. You can check drive, its compression state with HP Library and Tape Tools at http://www.hp.com/cposupport/information_storage/support_doc/lpg50128.html
Eugeny

Re: DLT 8000

CA704979 — Fri, 04 Apr 2003 15:54:53 GMT

The previous replies are both entirely correct. Hardware compression does the buffering and compression of the data in the cpu and internals of the tape drive. It is optimized for the particular type of media and drive type. Using software compression not only impacts the CPU on the server being backed up and/or the CPU of the backup server, it also will slow down the backups because the server must compress the data before it is sent to the drive. This will keep the tape drive from getting a constant data stream. The result is that the DLT drive stops the tape movement when not enough data is present. Then it must rewind, reposition, and then start writing again. This decreases head life for the drive very rapidly and will cause a drive failure.

Using the built-in compression will greatly aid your backups under windows. It also will allow the drive to modify write speeds so that it will not do the "shoe shining" of the drive.