Very slow restores from Fiber attached MOSLEMS LTO tape drive using HP-XX 11.31

[Mark Smithers]

This all started with a brand new installation of HP-UX 11.31 March updates and DP 6.20.  I had horrible backup speeds (< 1.5MB/sec) and HP provided me some patches to fix the situation.  My backup speeds are now acceptable but restore speeds are still < 1MB/sec.

I have updated the firmware to 5.50 for the library and H68W for the drive.  I also patched DP with the latest patches.  Still the same though - OK backups very slow restores.

I used tar to perform a backup of a 39GB directory and that wrote out to tape in a similar time as DP.  Now trying to restore a file from the TAR archive is giving me a speed of < 0.5MB/sec.

The only other detail I have seen is that looking at CV MSL while the drive is being used shows up a lot of "seeking" going on but I'm not sure if this is symptom of the fault (i.e.. Is the drive seeing a lot of errors)

Has anyone else seen this or maybe even a resolution to the problem?

The hardware is a BL860 fiber attached via switches (not VC) to a MSL2024 with a single LTO4 drive.

Many thanks for any help you maybe able to give.

Mark

[butti]

Hi,
Try this.
Set Parameter hires_timeout_enable=1 with Kctune.
Best regstes,
Butti

[Mark Smithers]

Butti,

Thanks for this suggestion which I can try on Monday.  I have not heard of this parameter before. 

May I ask why you think / know that changing this will help?

Regards

Mark

[Dennis Handly]

>Fiber attached MOSLEMS LTO tape drive

(You need to be careful with spell check.  You can edit your subject.  :-)

[Bob_Vance]

Did you ever resolve this?

I have the same problem w 11.31, MSL6000, and DP 6.1, but still with the DP 6.1 *backup*.

What patches did you apply to resolve your backup times?

bv