Log Error / %L2-ACCT_SVR-7-ISR_FIFO_USAGE_FLAG

[Ahmed Erfan Mehdi]

Hello Dear,

I hope you doing well,

I have noticed an accumulated error on log messages at 12000 core router.

LC/0/0/CPU0::Sep 18 17:40:18.150 : acct_svr[111]: %L2-ACCT_SVR-7-ISR_FIFO_USAGE_FLAG : ISR FIFO ring buffer usage is above threshold (838860). direction: 0 num_items = 839792

LC/0/0/CPU0::Sep 18 17:55:33.838 : acct_svr[111]: %L2-ACCT_SVR-7-ISR_FIFO_USAGE_FLAG : ISR FIFO ring buffer usage is below threshold (838860). direction: 0 num_items = 838609

Would you please advice me, what does it mean ? why the router showing this message ? Will traffic be affected by this condition?

Kindly your reply is needed

Regards,

Ahmed

[vmiller]

1.

%L2-ACCT_SVR-7-ISR_FIFO_USAGE_FLAG:

ISR FIFO ring buffer usage is [chars]  threshold ([dec]). direction: [dec] num_items equals [dec]

The process acct_svr detected the condition of ISR FIFO ring buffer usage above or  below the threshold. If the usage is above the threshold, the process acct_svr will bring the ISR FIFO  ring buffer usage back to below the threshold after a while. Traffic will not be affected by this  condition.

Recommended Action: If the message recurs, copy the error message exactly as it appears on the  console or in the system log, call your Cisco technical support representative and provide the  representative with the gathered information.

Possible bug. I'd open a TAC case.

[Ahmed Erfan Mehdi]

Hello Vmiller,

okay that is right. i ahve read the doc about layer 2 messages ... but i want to understand this error ... why did it happen ? what is acct_svr ? would you please explain it ...

Regards

[vmiller]

i can only speculate that it has to do with either tx or rx ring buffers.

The TAC could answer it.

[Ahmed Erfan Mehdi]

thank you buddy for reply.

Regards,

Ahmed

[Ivan Shirshin · Accepted solution]

Hi Ahmed,

Acct_svr is the Accounting server process that keep track of  accounting when it is configured on the 12k.  ISR is an internal  queue use to pass information between different APIs. 

Such errors are usually seen due to extra activity on the Tx of the accounting server.

Acct_server is used by multiple processes.  One of them is to collect  Netflow information from TCAM in the cards as well as Xconnect and MPLS  information.  So you don't have to configure accounting specifically for the  Acct_srv to be used. E.g. if you have a lot of Xconnects or MPLS traffic going through the cards - it can cause this error message.

This message is not traffic affecting, and in most cases it is seen due to the DDTS CSCsz87714.  The release notes are:

Symptom:

The error message from accounting server regarding threshold exceeded  may be seen in the logs

Conditions:

The DDTS is not specific to any Xconnect id setup and does not require any trigger. The issue is generic to the MPLS traffic accounting in ingress. We have a Xconnect Id field in the MPLS Accounting profile, which is required only in the TX direction. Since this profile is common to both ingress and egress, we populate this field as 0 in the ingress. This causes the garbage values to be generated for this field, leading to large no. of entries in the NFTCAM. This causes the ISR FIFO full.

Workaround:

Reloading the LC may cause the issue to be resolved for sometime. But, it will reappear as the same traffic would be flowing again.

Kind Regards,

Ivan Shirshin

**Please grade this post if you find it useful.

[Ahmed Erfan Mehdi]

well said dear Ivan,

thank you for support.

Regards,

Ahmed

[Ivan Shirshin]

Welcome, Ahmed :-) Thanks for rating.

Kind Regards,
Ivan Shirshin