About fragment size in a HFS file system

[fly_fisher]

Hi all,

Is 4k a good fragment size in a HFS Filesystem which block size is 32k ?

This filesystem is going to be used as Data Wharehouse(oracle).

Thank you very much for your help.
Regards.

[John Palmer · Accepted solution]

Data warehousing = big database files.

Why are you concerned about fragsize in a filesystem that's only likely to contain a few large database files?

I would recommend that you use a VXFS filesystem rather than HFS. As it's extent based, you don't really have to worry about the blocksize. It's much faster to recover in the event of a crash and doesn't require the 10% minfree space overhead.

Regards,
John

[John Bolene]

Only use HFS if you have to, VXFS is a much better solution.

And yes 4K is a good fragment size to use in a 32K block. It is usually 8-1 or 10-1.

[Wodisch]

Hello Rafael,

I guess the reason for you posting stems from the Database admins?

Have a look at the discussions over there:

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x6dc0c8ecad09d6118ff40090279cd0f9,00.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x85b479bffde7d4118fef0090279cd0f9,00.html
http://www.docs.hp.com//hpux/onlinedocs/os/11.0/tuningwp.html#diskperf

HTH,
Wodisch