HP-UX, EMC, fibre performance problems

[regsniff]

Hello all:

I am working on a project where we have an HP N-class connected to an EMC frame through redundant 1Gb fibre (no load balancing across the two fibre paths). The EMC is configured using metavolumes with 24 disks per meta, so spindle speed should not be an issue.

We are seeing some very erratic performance, most notably, limitations of single threads. For example, if we perform a simple 'dd' on any file on an EMC filesystem we see no more than a max data transfer rate of 21MB/sec. If we try the same command on a a file located on an internal drive we can see 30-35MB/sec, reaching maximum spindle speed.
The best we can ever seem to achieve down a fibre channel is about 50MB/sec.

The ASP vendor cannot (or will not) recognize that 21MB/sec is low and they go so far as to state that HP and EMC say this is adequate. I am at a loss for answers.

Does anyone else have a similar configuration and if so can they see this same type of activity?
Any thoughts would be appreciated.

Regards,

 

[pmwut5]

I'll try on an L-3000. See what I get. Although I am not using meta volumes.

Where are you determining the write speed. glance/brocade switch ?

Regards

Paul

 

[skyl1nev6]

A couple of things....How are you metavolumes configured??? Are the disks mirrored, striped, or concatenated? Also how much cache is in the EMC and how much raw storage? Another area to peek as is your fibre channel patches......I am seeing around 70 per sec on our frame with roughly the same config.... Matt
Sr. Systems Administrator

 

[kojack96]

I have an N Class conneted to EMC Clarion FC4700 does this match your setup what type of DPE do you have??