CSS 11500 Series LOGs

[Marko Bursac]

Hi everyone,

I need some help about one type of CSS 11500 LOG messages:

OCT 12 07:47:03 1/1 273 WCC-6: Computing slow start parameters for newly activated service index 4

OCT 12 10:25:05 1/1 274 WCC-6: Computing slow start parameters for newly activated service index 3

OCT 12 11:19:49 1/1 275 WCC-6: Computing slow start parameters for newly activated service index 3

OCT 12 11:26:33 1/1 276 WCC-6: Computing slow start parameters for newly activated service index 3

OCT 12 12:20:37 1/1 277 WCC-6: Computing slow start parameters for newly activated service index 3

OCT 12 14:04:32 1/1 278 WCC-6: Computing slow start parameters for newly activated service index 4

OCT 12 14:04:53 1/1 279 WCC-6: Computing slow start parameters for newly activated service index 5

OCT 12 14:05:01 1/1 280 WCC-6: Computing slow start parameters for newly activated service index 4

I was trying to find some explanation about these LOGs, but I didn’t have any success.

My questions are:

1. What does this LOG type mean?

2. Does it signalize some issue on the service?

Thanks a lot for the help!

Regards,

Marko

[Kanwaljeet Singh]

Hi Marko,

Please go through the below link:

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v8.20/configuration/content_lb/guide/ContRule.html#wpmkr1150644

Just pasting some content. Read the details please.

Slowly Starting Connections on a Service

When you configure a content rule with the least connection (leastconn) load-balancing method, a service on the rule with the fewest connections receives the next request. If you activate a service on this rule, the service may become flooded with requests.

To prevent the flooding of connections on a newly activated or reactivated service, you can enable the slow-start feature on a content rule configured with the leastconn load-balancing method. Through this feature, you can configure:

•The rate that an activated service receives connections. The slow-start rate is applied globally to all leastconn content rules on the CSS. By default, the rate is enabled with a default value of 3. If you disable the rate by setting it to 0, the slow-start feature is disabled on all leastconn content rules configured on the CSS.

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Note We recommend that you do not change the slow-start rate default value.

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•The maximum time that the service remains in the slow-start process. The slow-start timer sets the number of seconds that the service on a leastconn content rule is in the slow-start process. The timer is applied to a leastconn content rule. By default, the timer is disabled. If the timer is disabled, the slow-start feature is disabled on the rule.

When you enable the slow-start feature on the CSS and a leastconn rule, a service on the rule enters the slow-start process when you:

•Add and activate a service to the rule

•Reactivate a service after suspending it on the rule

•Activate the rule

When you activate a rule, it starts to load balance the connections on its services. The service with the least number of connections is selected to enter the slow-start process.

When a rule has only two services, only one service can enter the slow-start process. When the rule has more than two services, a newly activated service can enter the slow-start process when one of the services is currently in the slow-start process and the other services are out of the slow-start process.

A service in the slow-start process slowly continues to receive connections until either the slow-start timer expires or its connections equal the number of connections on the other active services of the rule. Then, the service exits the slow-start process and starts receiving connections as it normally would.

Regards,

Kanwal

[Marko Bursac]

Hi Kanval,

Thaks for your fast reply!

I have already read this article, but If I understood correctly,

you can use the slow-start feature on the CSS switch,

only if you configure a content rule to use the least connection load-balancing method?

On my CSS switch I have configured all content rules to use only roundrobin as a load-balancing method.

My question is why do I have these LOGs when I use roundrobin method?

One thing more that confuse me is that all services on the CSS are in Alive state,

and they didn’t go up and down on 12.10.2012.

Furthermore, I had these LOGs yesterday, and today.

Do you have any idea why is this happening,

and do this LOGs signalize some issue on services?

Thank you in advance for any help you can provide!

Regards,

Marko

[Kanwaljeet Singh]

Hi Marko,

I did some research about the log; this message is in the code for informational purposes. When a service is activated, and

comes alive, this message just gives information at the service level, that a service has come alive, and is providing this info to the rule, so that if slow start is configured, to recalculate the parameters needed.

Since slow start is not configured in your CSS, nothing is done, as the rule checks to see if slow start is configured before doing anything.

From the code it appears this message will be printed every time the service goes to Alive state.

In your case services never went down as you said but this message can also be triggered by the following:

- When an active service is added to a content rule configured for slow start( in your case no content rule is configured for slow start it seems)

- When a suspended service on a slow start content rule is activated

- When a slow start content rule is activated

So you can see that a service may not be transitioning to the ALIVE state when you see this message.

Now, this message can be ignored and you can even get rid of it by reducing the logging level. But if you are worried why it came when you did nothing of the above, i would suggest opening a TAC case for detailed investigation.

Normally Existingsessions to a service are not impacted even if a service does go out-of-service or is suspended.  Only new connections will not be sent to the service until it is ACTIVE.  You can safely ignore these messages.

Regards,
Kanwal

[Marko Bursac]

Hi Kanwal,

I will do some more research on CSS switch to be sure that this LOGs don’t signalize some issue with the CSS.

Thanks for the reply!

It was helpful.

Regards,

Marko