Hardware compression

[tim55]

I am using an external HP SCSI C7438A Dat72 drive on Windows SBS 2003 using Backup Exec 10 SBE. When installing I chose to use the Backup Exec drivers, and had not previously installed the HP drivers which came with the tape backup unit.

Everything works fine, but selecting to use hardware compression appears to be no different than selecting no compression at all and I can get no more than about 33GB on the tape. I am using standard HP Dat72 tapes.

I have loaded the latest HP LTT software, updated to the latest firmware, enabled hardware compression and the tests show that I am getting 2.2:1 compression.

What I refuse to believe is that with a wide range of system files, Exchange files and general Word and other database files being backed up, that the actual compression on a real backup can be 1:1. There has to be something which although Backup Exec appears to allow me to use hardware compression, in fact it is not.

Can anyone suggest a way forward or further tests I can carry out?

Thanks.

 

[SkreeM]

I have found that with HP drives you need to use the latest versions of the HP drivers rather than the veritas ones to get hardware compression to work. If you wish to stay using the veritas drivers enable the backup job for hardware compression if available otherwise software and it should use the software compression. On all Dat72's ive installed i use the HP drivers as they work well.

 

[tim55]

Thanks for the advice - I have heard similar ideas in other threads.

What is the best way to use the HP drivers instead? Is it just a case of using Device Manager or is there anything else I should do?

Tim

 

[tim55]

Incidently, I need to make sure I am reading the facts correctly. I am going to the device in Devices and on the right-hand side it shows the media in the drive, which is the one I have been testing with. Right-click and select Properties and up comes the Media Properties box and on the Statistics tab are the figures I have been looking at.

Having just done a test full overwrite backup, it shows Used capacity 18.1 BG, Total capacity 33.8 GB Compression ratio 1.18:1 and Bytes written 18.9 GB. How are these figures arrived at?

Thanks.