topic RE: Root cause of high latency in ExtremeSwitching (EXOS/Switch Engine)

Root cause of high latency

hafiz — Mon, 06 Jun 2016 13:20:00 GMT

Hi guys,

I need your expertise to help me troubleshoot my issue. My current infrastructure have summit x450a(redundant) as core switch and blade servers(hosting VDI).

However, I noticed there is high cpu utilization on those core switches. Plus I can't ping the VDI vlan eventhough there is no acl. The VDI don't have any issue connecting to the internet.

I attached some screenshots for your reference. What I really want to know is where is the root cause of this issue. For your info my switches use XOS 12.XX

Thank you in advance

RE: Root cause of high latency

Edward_Tsui — Mon, 06 Jun 2016 13:32:00 GMT

what is the uptime of your switch?

RE: Root cause of high latency

Ron_Huygens — Mon, 06 Jun 2016 13:35:00 GMT

Hi Hafiz,

A good start is to find out which process is causing the high CPU usage using the command "top"
https://gtacknowledge.extremenetworks.com/articles/How_To/Understanding-the-output-of-the-TOP-comman...

Usually, high CPU utilization needs to be diagnosed case by case.
If you are seeing network problems or problems on the switch you can check the "top" output.
If you see some processes each running at maybe 10 or 20% for a longer period, I would recommend opening a case with GTAC so it can looked into further.

RE: Root cause of high latency

hafiz — Mon, 06 Jun 2016 13:35:00 GMT

Here is the attachment after I ran top command. as u can see in the first row, is it possible to have high CPU utilization eventhough the STAT is "S"(sleeping)?

RE: Root cause of high latency

hafiz — Mon, 06 Jun 2016 13:36:00 GMT

just 1 week plus.because we have power trip last weekend.but this issue already happened almost 1 month

RE: Root cause of high latency

SchmuFoo — Mon, 06 Jun 2016 13:56:00 GMT

You could check if there is a loop via ELRP command and in addition, use the "show port utilization" to look for Ports with unusual High packets-per-second.

RE: Root cause of high latency

bw447 — Mon, 06 Jun 2016 19:41:00 GMT

We had some latency issues a while back. Command we used a lot was "show port statistics" It does a good job of showing RX/TX , Broadcast and Multicast packet counts. We saw that we had a high amount of Multicast. GTAC recommended we upgrade our EXOS version. We are currently running 16.1.1.4. Since we did that we haven't had any issues come up.

RE: Root cause of high latency

hafiz — Mon, 06 Jun 2016 19:41:00 GMT

This is the result after I ran the command 🙂

RE: Root cause of high latency

hafiz — Tue, 07 Jun 2016 12:29:00 GMT

I think I have found the solution.but I haven't try yet.refer below 🙂

https://gtacknowledge.extremenetworks.com/articles/Solution/High-CPU-Utilization-from-Process-Nodemgr