File system performances

[TOMAS BERNABEU]

EVA8000 disk array with 8 ports and 56 disk 15k, conected to HP9000 server with 6 HBA.
LUN 500 GB.
Access raw mode to this LUN shows 1,2 GigaBytes/sec.
From File system veritas version 4, no more than 500 GB/sec.

Kernel ?
Tunning ?
Others ?

[Hein van den Heuvel]

First I thought scsi_max_qdepth, but that would apply to raw as well. Still, between different buffer sizes and more, or less, bursty behaviour that could make a difference.
Have you raised scsi_max_qdepth from the default 8 to 50 or 100 or so?

Anyway, somehow I think you know an awful lot more then you show in the question. Please don't let us waste time speculating:
- Is the test read, write or mix?
- Sequential, random or a mix?
- Did you try presents the storage as mutliple luns and use multiple mointpoint?
- Did you try to use LVM to create the 500 GB lun into smaller LV's?

What reasearch have you done for existing advice?
google: +hpux +filesystem +performance +site:hp.com

May we assume you read:
http://docs.hp.com/en/1435/NFSPerformanceTuninginHP-UX11.0and11iSystems.pdf

That document would be a good starting point, but there is more out there.

and then there are outside documents like:

http://oss.sgi.com/projects/xfs/papers/xfs_white/xfs_white_paper.html


Hope this helps some,
Hein van den Heuvel (at gmail dot com)
HvdH Performance Consulting

[Hein van den Heuvel]

Here is an other critically important whitepaper for those interested in file system performance and tuning

http://docs.hp.com/en/5576/JFS_Tuning.pdf


btw... I knew (from Dave Olkers references) that is should be under docs.hp.com, but I could not find it neither through simple search for "JFS Tuning and Performance"
nor by hierarchical browsing
Google found it in one:
+"JFS Tuning and Performance" +site:docs.hp.com



Hein.

[Dave Olker]

Hi Hein,

Thanks for pointing out the problem of locating Mark Ray's VxFS Tuning guide. I looked around docs.hp.com and I was only able to find it on the HP-UX 11i v1.5 and v1.6 pages under System Administration -> technical Papers. Not exactly the first place I'd think to look.

I've sent an email to Mark Ray asking him to change/add the paper to more locations on docs.hp.com to make it easier to find.

Regards,

Dave