StorageWorks Dat 72 problems

[Craig_79]

Compression is not working. Drive says compression capable = True but compression enabled = false. Problem is I can't change it, it's greyed out. Using Veritas software. Running MS SBS2003 OS. Using HP Dat 72 tapes. Why am I having this problem?

[Satish M.S.]

Craig:
One way to enable hardware compression is to run a test called the 'Compression Test' using the Library and Tape Tools Diagnostic Software that can be downloaded from
www.hp.com/support/tapetools

When you run the compression test, you will see a message that basically tells you that 'hardware compression may be disabled, would you like to enable it?' Choose 'Yes'. This is one way to do it, although it doesn't really guarantee it.

Have you also tried to stop all the backup services and restart them? Many a time this resolves the issue as well.

[Craig_79]

I ran Ltt and bytes written & bytes read are the same, meaning 1:1. So I upgraded the Dat72 firmware from v303 to v312. Reran Ltt and now looks like compression is 2.2:1. thought I would be good to go, but unfortunately A full backup revealed 1:1, and can't do full backup still.

[Marino Meloni_1]

Standard settings on DDS tape set the compression on but allow SW overwriting the setting.
this mean that if you boot your server, after a power down, the compression is enable by default. if another backup application is then started, this application can overvrite the default setting, and set compression off.
This can explain why some time you see compression enable and some time disabled.

[Craig_79]

Something very wrong with Veritas, it still says in various places the firmware is still v303. I think tomorrow I will reinstall Veritas. Shall I use HP drivers or Veritas drivers, is there any consequences/advantages to either?

[Craig_79]

Thanks Marino, Then I am correct in thinking the software (Backup Exec) is the main suspect here? I will reinstall. Which drivers should would you use, Veritas or HP drivers. I always like to go with Manufacture drivers, but unsure in this case.

[Marino Meloni_1]

I usualy use HP drivers. in case of problem, I try with the Backup application drivers.
Be sure to have a Backupexec version supporting the DAT72.

marino

[Craig_79]

It does, just checked.

[Craig_79]

No go. I un / reinstalled Veritas without their drivers. Backed up .986:1. That is not compressed, it is larger. Used hardware only compression selector in Veritas. Will try hardware then software compression tonite. What if veritas compression is off and let hardware do things itself? Ever tried that?

[Satish M.S.]

Craig:
I was on the Veritas Support Website and found a few documents of interest. A few questions to ask you though:
1. What version of Veritas are you running
2. What do you have running for an OS?

Please click on the following link(s):
http://seer.support.veritas.com/docs/258821.htm
Document #: 258821, http://support.veritas.com/docs/258821

This document basically outlines as to how to go about enabling compression whether be it software or hardware. The document outlines as to how to enable the software compression. On the contrary we will have to make sure hardware compression is enable for optimum performance/results. So, kindly try the following:-
1. In the Backup Job Properties, click General under Settings .

2.Select Hardware (if available, otherwise software) from the Compression type drop-down list.

3. Continue with configuring the rest of the backup job, and then click Run Now.

Restart Veritas BackupExec for the changes to take effect.