Maximun I/O size?

[Jessica Chou]

what is the maximun I/O size of
HP-UX B.11.00 U 9000/800? Is it 64K or larger?
I need to know this at considering Oracle's extent size.

Thank you.
Jessica

[CHRIS_ANORUO]

Use 8K for db_block_size for 11.00 and 4k for 10.20

[Rumen Ginev]

I thing you mean the file system block size.

vxfs: 1K-8K (1K default);
hfs: 4K, 8K, 16K, 32K, 64K (4K default)

It is good idea db_block_size = "file system
block size".

Rumen

[John Palmer]

I have done some tests on a couple of L class servers (SCSI and Fibre channel disks) using dd:-
dd if=/dev/rdsk/c?t?d0 of=/dev/null bs=1024k

glance reports a typical transfer rate of 35Mb per second and 140 transfers per second.

This gives an individual I/O size of 256Kb.

[John Palmer · Accepted solution]

However if you use a VXFS filesystem under LVM by dd'ing a file, the transfer size is 64Kb.

So it looks as though the raw disk I/O limit is 256Kb and the VXFS filesystem limit is 64Kb.

Hope this helps,
John