High CPU load on SUP2 while broadcasting, could this make problems?

[patoberli]

Hello

I'm seeing >95% CPU load on our SUP2 in a 6500 chassis while broadcasting.

Could this lead to any problems?

The 6500 is also doing the routing between our ~30 Vlans and the FWSM.

Is there anything I could do to lower the priority of the Broadcast task so other traffic will not be impacted, or is this anyway the case?

We're running the latest IOS on the SUP2 and also on the FWSM.

Thanks,

pato

[ankbhasi]

Hi Pato,

Yes if the CPU is too high it can degrade the performance at that particular time.

You can think of implementing broadcast supression or traffic strom control. Have a look at this link

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/swconfig/bcastsup.htm#wp1027685

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/swconfig/storm.htm

HTH

Ankur

*Pls rate all helpfull post

[patoberli]

Thanks, very interesting read (am not yet throught completely).

I forgot to mention that we use Broadcast to image our computers (with Symantec Ghost) which we do every few weeks (school).

This means that we need a high transfer rate for broadcast.

The main problem is this bug here: CSCei56437

Luckily the broadcast is usually finished within 15-20 minutes :)

But yeah, we're not absolutely happy.

Will read further now that document.

Thanks,

pato

[patoberli]

Completed the read and just found out that I made a mistake in the title :/

I wrote broadcast but actually meant multicast!

Any ideas how this would look with multicast?

[ankbhasi]

Hi Pat,

In the same traffic strom control link you can find an option for multicast strom control also to set a multicast strom control level.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/swconfig/storm.htm#wp1021340

HTH

Ankur

[patoberli]

Hi Ankur

Thanks for the link.

Sounds good, but what will happen if it starts to drop the packets?

Will that be detected by the Ghost server or will all my "to be imaged" computers then not work?

[ankbhasi]

Hi Pat,

I believe because its a multicast packet and I beleive your multicast stream will be on UDP so I do not think that if the packets get dropped because of multicast strom control ghost server will not be able to detect so I believe computers then not work.

But as you said it does not happen for very long time? and also for how many times a day this multicast streams are sent? If it is once and for short time you can let it work as it is.

HTH

Ankur

*Pls rate all helpfull post

[glen.grant]

Is broadcasting or multicasting ? Multicasting will bury the cpu if not done right . We had a person mutlicasting ghost on a Sup 720 and everytime he did this it would bury the cpu at 95-100% and we could not even get into the box when that happens . Probably have to set it up to handle mutlicasting .

[patoberli]

It's multicasting.

I still can access the Sup2, but all the commands are slowed down.

I allready limited the multicasting to the only few VLANs needed.

Is maybe something with QoS possible?

The good thing is, it's only for around 20 minutes every few weeks.

The bad thing is, my manager doesn't like the possibility that it could have an impact on the network.

We're usually multicasting around 20 - 30 systems.