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C11 CDN huge traffic after purging

George Dorgan By
George Dorgan
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Page no: C11

PageNo: S05g

 

see also under common server issues

Server load at that time on 07/20

Server load at that time on 07/20 - Click to enlarge

Our server problem on 07/20 was caused by our CDN. We purged the whole cdn cache and their crawlers start caching all our static content again. The problem was that they started too many connections to the our server. The traffic was almost 800% higher than the usual traffic. This is problem of the CDN, they must send regular queries for fetching our content. This traffic is not seen by the Google Analytics, because it is directly to our CSS files. Nothing related with the site. So Google Analytics can track only when the code is installed on that page. It can’t track the traffic to our static files.

We fixed that issue changing the apache and nginx limits to higher. Now we can handle MaxCDN traffic. But it is good idea to purge only some files, not the whole cache. It will save us so many unnecessary queries.

Work-around:

MaxCDN explains that we should put *.pgn and *.jpg on the CDN rejected files list and remove it after one hour. This gives one hour time to load all new code, e.g. Java Scripts or plugins. The pictures would be loaded later.

Not empty reject list

After the chat with MaxCDN, we discovered that strangely the rejected list was not empty.

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