HP-UX HBA Queue depth settings?

[Adam Garsha]

In the EVA 4/6/8000 best practice docs I find this quote:

"Pay particular attention to queue depth management for HP-UX. For HP-UX, the default queue depth is eight I/Os per LUN. This is insufficient for typical configurations that use only a few LUNs. You can find additional information on this subject in publications within the HP-UX community."

Where can I find out about recommended settings for HP-UX and how-to?

Thanks.

[Uwe Zessin · Accepted solution]

"within the HP-UX community."... ah, yes. Very helpful.

Looks like the competition has made their homework:
http://publib.boulder.ibm.com/infocenter/dsichelp/ds8000ic/index.jsp?topic=/com.ibm.storage.ssic.help.doc/f2c_aghpfqudep_laxtvw.html

[sajeer_2]

Hi Adam,

To set the SCSI queue depth,you have to use scsictl command.
To see the the current queue depth,
scsictl -a -m ir /dev/rdsk/cXtXdX
cXtXdX is your LUN device file name.

Queue depth value can be 1 to 255.All the disk devices will not support the maximum value settled by this command.This depends on disk device also (see man scsictl)

To change the queue depth,for example,

scsictl -m queue_depth=21 /dev/rdsk/cxtxdx
Will set queue depth to 21.

About the recommended settings,I have read in one of the product document as
queue depth = 256 ÷ maximum number of LUNs

hope this helps

sajeer

[Peter Mattei]

I wrote a short summary regarding this question.
Find it attached

Cheers
Peter

[Adam Garsha]

One last question:

Is it ok/do-able to change the queue depth while the disk is online and active?

I am looking through docs now, haven't seen mention yet.

[Peter Mattei]

Yes this can perfectly be done online and starting with 11i will persist across reboots, opens and closes

Cheers
Peter

[Alzhy]

A client of mine who has an EVA5000 and who set up their LUNS at 500Gb (VRAID1 - single volume raw/filesystem)and used for Oracle OLTP (Oracle 9i) has found and settled qdepth @ 64 to be the most optimal... They're using dual 2GB paths to the EVA SAN.