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It looks like your CPU goes 100% during the archiving and is then nearly idle (tracking only).

I agree that with 11cores and so much RAM, it should behave a lot better. How many pages do you track per day?

How many rows in piwik_log_action (can you take screenshot of phpmyadmin overview of your tables with sizes + row count)?

Finally, a "quick fix" solution is to set timeout to 100000 so that you effectively disable "real time" reporting for "today" and only access yesterday and before. Today will be archived in the first archiving run of the day in your website's timezone.

How many pages do you track per day?
At the moment piwik is tracking between 60-70 websites.
How many rows in piwik_log_action (can you take screenshot of phpmyadmin overview of your tables with sizes + row count)?
The piwik_log_action table has 123486 rows and its size is 20MB.
Finally, a "quick fix" solution is to set timeout to 100000 so that you effectively disable "real time" reporting for "today" and only access yesterday and before. Today will be archived in the first archiving run of the day in your website's timezone.
Which timeout do you mean ? The archiving interval ?

Attachment: Phpmyadmin
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how many pages views do you track ?

The archiving interval ?
yes, in http://piwik.org/docs/setup-auto-archiving/

how many pages views do you track ?
About 10 000 visitors and between 60-70websites. The archiving interval is 3600seconds.

Attachment: Page Views
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Is piwik able to handle 10 000 visitis in 12h ?

Note: Why is the ticket closed? The issue is still there ...

Piwik should handle tracking without problem, the problem is that you process "today" report and "current week" current month current year EVERY hour. This is too much. There is a new archiving script in development that will make things better but in the meantime, put archive timeout to 10000 par exemple (every 3 hours) and it will be better.

Also please enable mysql slow query log to see if there any abnormal slow query.

EDIT: see: https://piwik.org/docs/setup-auto-archiving/