How to en-disable hardware compression on MSL lib's.

[BR734478]

Does anyone know how to enable or disable the hardware compression on the MSL5030 library ?

Logically I would think it was accomplished through the front touch display, but that doesn't seem to be the case.

Or is it done through the backup software (Arcserve running on a Windows 2000 platform) ?

Help is appreciated.

Regards
Christian

[Lewis Finch]

Christian, there is no way to do it through the front panel and by default hardware compression is enabled because it is faster than software compression.

[BR734478]

Thanks Lewis,
I have come to the same conclusion, however if a customer doesn't want to use any kind of compression neither hardware nor software, due to the fact, that it's the only way he can keep his drives streaming.
(When using compression the feed speed needs to be higher, 2-3 times higher than native speed, to keep the drives streaming, otherwise the drives will go into start-stop mode)

Is there no way of disabling the hw compression on the Windows platform with the MSL lib's?

[Lewis Finch]

Hi Christian,

Compressed data should give you better performance not worse. You'll find a lot of information on this here.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=lpg50460

[Christian Jonsson]

I have a similar problem with a MSL5030 library using Veritas Backup Exec 9.0. When I view the Drive Status Summary in the webadministration interface to the library, it says that compression is off. I can however navigate to the drive configuration. There I have the option to change Data compression from off to on. When I submit the changes it says "Drive configuration update was successfully completed". Back at the Drive Status Summary it still says it's off. I can also view from the touchscreen display that compression is off. How do I enable the hardware compression?

The current compression rate is 1,451:1 and in the software I've selected to use hardware compression if available otherwise none.

Please advice

Best regards
Christian

[CA989818]

If you don't already have it, download Library and Tape Tools from HP. Move a tape into each one of your drives. Stop all backup services, start L&TT's click on a drive and go to test, check the box, and choose compression test, If compression isn't enabled you will get a prompt asking if you want to enable it.

[Christian Jonsson]

Good job. That little trick is not in any instructionbooks. The program confirmed that I had the compression on and when I tried to stuff a tape with more than 97Gb (tapestorage without compression) it increased the compression rate automatically. I guess I have nothing to be worried about. Thanks a million for the information.

[meloni]

you have to know that all the high level backup software have the ability to set or reset the Hardware compression.
The setting is a flag on a scsi page in the tape, send via a scsi command. this flag can be set or reset.
By default the majority of the tape drive have compression on with possibility of Software overvrite, that mean that the default is Compression on, but a scsi command could change the status.

marino