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I have a little concern regarding HP Procurve switches. I am monitoring an important number of HP switches, and I observed that after the reboot, few seconds later CPU usage raised up to 100% and stood there for like 20 minutes, then came back to normal. I could not detect any issue, and after a quick research on the internet, I found that it's a common issue for some HP switches.

I would like to know if anyone here has more details/information on the exact switch series having this problem (for my case, most switches showing this behaviour were HP J4813A ProCurve Switch 2524) ? Is it normal? Is there a way to avoid this or see what's going on the background of this behaviour ?

Ron Maupin
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Mariyam
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    Are you seeing any performance problems in your network during that time? – Ron Trunk Feb 23 '17 at 12:19
  • No, no network performance problems reported by the users. – Mariyam Feb 23 '17 at 13:25
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    You should edit your question to include the configuration of one of the switches in question. – Ron Maupin Feb 23 '17 at 15:05
  • Does HP still provide lifetime ProCurve support at no extra charge? If it's a known issue, they probably have at least a canned response/explanation for it. – Todd Wilcox Feb 23 '17 at 18:21
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    Two years ago I posted a question about the same issue with two different models from HP. Maybe it can help you. http://networkengineering.stackexchange.com/questions/5765/procurve-cpu-at-100-for-several-minutes-after-reboot – Daniel Yuste Aroca Feb 23 '17 at 20:33
  • Thank you very much @DanielYusteAroca . Do you know if there is a way to avoid this ? and are ProCurve Switch 5406zl and HP 2520-24G-PoE Switch (J9299A) the only series showing this bahaviour? – Mariyam Feb 24 '17 at 11:47

1 Answers1

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When the switch boots, one of the initialization tasks is creation of encryption keys. Having the keys created in advance means that later, when a feature such as SSL or SSH that uses the keys is configured or used, there is minimal delay in the availability. This task takes a few seconds before it ramps up, depending on the switch model, the configuration being loaded, and the software revision. Even though the task consumes up to 100% of the CPU, it runs at a very low priority. Therefore, if another task requiring CPU cycles is started, this low priority task will back off (So, users should never have any performance issues). If this initialization/key generation task runs uninterrupted by higher priority tasks, it takes about 10 minutes to complete. If the CPU is busy with other tasks, the completion time will be extended.

Faizan - Network Consultant HPE

Faiz
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  • Thanks @Faiz . Does this occur on all HP switches? Could you please provide the exact series that may show this behaviour ?

    Thanks again.

     – Mariyam Feb 24 '17 at 16:04
  • Most of the HPE Procurve based switches like 2500, 3500 series would have this behaviour. – Faiz Feb 24 '17 at 18:57