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Hardware Compression turned off

Alan Sauerbrei
Occasional Visitor

Hardware Compression turned off

I have read some of the postings relating to hardware compression on tape backups. My situation is similar to some of the postings, but I'm not sure that I ever saw a solution.
Drive: Compaq DDS4 20/40 DAT
Server: Proliant ML370 G2
OS: Small Business Server 2003
Backup software: Veritas BE 9.1
Dip switch settings 7 & 8 ON (compression, do not allow host update)

When I reboot the server the drive settings show Compression capable:TRUE Compression Enabled: True

After I run a Backup from BE the settings go to Compression capable:TRUE Compression Enabled: FALSE

From that point compression no longer occurs.

1:1 even if I backup a test Text document that has many rows of the same characters.

If Backup Exec is shutting off compression when it finishes, What will turn it back on?





P.S. This thread has been moved from General  to Tape Libraries and Drives. - Hp forum Moderator

Michael Schulte zur Sur
Honored Contributor

Re: Hardware Compression turned off


could you give us your exact tape model, please?


Alan Sauerbrei
Occasional Visitor

Re: Hardware Compression turned off

The Drive is an internal SDT-10000
The tape media is TDK DC4-150
Microsoft Driver 5.2.3790.0 10/01/02

If there is a more specific model number I don't know where to find it.
Khee Chan

Re: Hardware Compression turned off

I am going by my experience with BE 8.6 on WinNT ...

I understand that you are using the default Microsoft driver for your SDT-10000. Are you aware that Veritas have their own set of tape drive drivers? The latest version for BE 9.1 can be downloaded from .

There should be a check box in the tape drive properties under BE to enable compression. If you don't see it or if it made no difference then you should consider installing the Veritas drivers for Sony 4mm tape drives. On WinNT they have one set for all other 4mm drives and another set just for Sony 4mm drives.

As for the compression settings on the tape drive itself, I would recommend you use the Sony default (7=ON, 8=OFF) - "compression enabled at power on, host allowed to control compression". Docs on the SDT-1000 are available at .

Hope this helps.
Alan Sauerbrei
Occasional Visitor

Re: Hardware Compression turned off

Thanks for the tip on the Veritas driver. I was already seeing the compression check box with the Microsoft driver, but I updated to the latest veritas drivers and set the DIP switches to 7 on 8 off just to make sure that the driver was not the problem. Last night's backup still showed 1:1 . Backup parameters are set to use hardware compression if it is available.

I am looking at a NAS device for future growth. Any recommendations?
Khee Chan

Re: Hardware Compression turned off

Does Win2003 come with NTBACKUP? If it does, try NTBACKUP with hardware compression. The option can be selected in the GUI - "Backup" > "Start Backup" button > "Advanced" > "If possible, compress data ..."

Or from the command line (see NTBACKUP /?). I prefer the command line option because I see the log messages right away.

As a last resort, try the SDT-1000 on another system to see if it there's not a fault in its firmware or the drive itself.