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How to enable/disable drive compression on HP LTOx drives.

In this Document

Goal

Solution

References

Created from <SR 3-7388159091>

Applies to:

Goal

Certain user applications (specifically HP Data Protector) specify that compression should be switched off at the drive level.  By default the drive has compression switched "on" although the drive will detect whether the data incoming is compressed or not and if it is, it will not compress further.

To quote HP....

"The data compression hardware in HP Ultrium drives can detect whether incoming data is already compressed and will not attempt to compress it again. The drive can switch dynamically and automatically between compressing and non-compressing modes, thereby optimizing both compression ratio performance and data rate. As this mode of behavior is embedded in the Ultrium format, there is no need for host application software to switch the drive’s data compression on and off and HP strongly recommends to leave data compression at its default of 1 (on)."

Solution

To change the setting for compression:

1. Download and run LT&T DIagnostic utility.  (See doc 1388614.1)

2. Select the GUI.

3. Select the device to test (the 'By Product' or 'ByConnection' tab)

4. Click 'Test'

5. Click the box next to the device. The 'Test Group' menu displays all of the tests available.

6. Select the 'Device Configuration' test.

7. Select 'Options'  and set 'Enable/Disable Compression' to Disable.

8. Click 'Start'

Refer to IBM/HP LTO - How to Check the State of Hardware Data Compression [ID 1516647.1] to verify compression settings.

References

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