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fbackup: Why do jobs run slower on new HP-UX machine?

 
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Advisor

fbackup: Why do jobs run slower on new HP-UX machine?

Hi all,
I am running an fbackup job on a 9000/785 box with HP-UX 10.20 A to backup some files on a couple of HP-UX 10.20 machines across the network to another HP-UX server with an external tape drive.
Recently I have changed the server's hardware from a 9000/800 machine running HP-UX 11.11 and a DDS 4 tape drive to an IA64 based machine with HP-UX 11.31 using an DAT72 tape drive.
Before the change the job has run for approx. 50 minutes but now it takes 4 hours!

Any idea about the reason?
2 REPLIES 2
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Valued Contributor

Re: fbackup: Why do jobs run slower on new HP-UX machine?

Hello Frank,

the reason for this might be that the tape is faster, but the collection of data is not fast enough. So your tape drive has to do a lot of repositionings, which is not good for the media and also the tape drive.

You might check the following document:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=lpg50460

I think you need to make it somehow faster, maybe more reader processes in fbackup. Also using a remote tape might be the issue, because fbackup uses a generic tape model for this. Maybe there is a way to tell fbackup what tape drive model you use to make it more efficent, but I am not a fbackup specialist.

Ralf
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Advisor

Re: fbackup: Why do jobs run slower on new HP-UX machine?

Hi Ralf,
sorry, I've got my issue settled in the meantime by our consultant. There have been some nonsense default values for fbackup:
blocksperrecord 32
records 32
checkpointfreq 32

We have replaced them by these new values:
blocksperrecord 8192
records 64
checkpointfreq 4096
and fbackup runs like hell again.

Anyway the document that you have mentioned is very interesting! Thanks for the link.

Kind regards,
Frank