Load on different I/O channels

[Karthik_2]

We have performance related in one of our servers and we have 4 fibre channel controllers connected to around 500 disks.
Currently we are looking for ways to move/distribute the load across the different controllers or if the controllers are the bottle neck will be buying new controllers.
Would like to know if there is any tool/trick to find out the load on each controller from unix .
Glance plus and measureware gives me stats about individual disks but not about the cumulative traffic through the controllers .
Any help appreciated.

Karthik...

[Steven Sim Kok Leong]

Hi,

You can monitor the I/O load at the FC switch port level since each FC card is connected by one FC-link to the FC switch port.

In my environment, I am using brocade switches for FC-communication between the servers and the disk array. I monitor the switch port load via the following metrics:
- bytes/sec
- discards/sec
- errors/sec

The Brocade silkworm switches come with a set of MIB objects which you can SNMP query to extract the above metrics for each switch port.

For a graphical presentation, you can interface the SNMP query results with MRTG or Cricket.

Let me know if you are using the Brocade silkworm switches. Will post up the OID names if needed.

Hope this helps. Regards.

Steven Sim Kok Leong
Brainbench MVP for Unix Admin
http://www.brainbench.com

[Karthik_2]

Steven,
We do not have any switch inbetween these
fc cards are directly conected to the emc
sym.Thanks for your help

Karthik...

[Kandaswamy Natarajan]

do you have glance?? if not
use sar.

sar -dM 5 100

This will tell you realtime the disk activity. translate the device files to i/o path. u will get the answer

[MANOJ SRIVASTAVA]

Hi Karthik

On the SYMGUI of the EMC please go to the FA monitors and check for the activity for each FA .It is a very GUI and can be operated with ease.This would give you the activity on each FA . Also sar -d can give you the diskactivity for disks the average but it will be quite cumbersome as you have 500 disks.

Manoj Srivastava

[John Poff]

Another option to consider is the EMC PowerPath software. It is supposed to balance the load across controllers for you.

[Bill McNAMARA_1]

vxvm with an additional licence does real load balancing.
With lvm it'll be possible end 2002 I've heard.

Later,
Bill

[Jordan Bean]

Call your SE and discuss acquiring PowerPath and Symm Optimizer. If the majority of IO is Oracle related, also ask about DBtuner and other related products from Precise. If you're looking for performance charts from the Symmetrix point of view, bring up Workload Analyzer in the discussions. I've found a decent performance monitoring package called SOS/9000 from Lund which will breakdown IO by pv, lv, vg, and channel.