A link-related story --------- server IO and network traffic surge

Environment:Ubuntu + Nginx + php-cgi + Wordpress

I was surprised to find that the I/O read/write speed and the inbound/outbound network speed both increased by 10 times.. The following figure shows the number (CPU, I/O read speed, I/O write speed, network outbound speed, and network Inbound speed in sequence) in normal cases. If there is a problem, it is not retained, but rememberIO read/write speed is around 250 kb, and network outbound speed is between 2 Mbit/s ~ Between 5 MB, the Inbound speed is also around kb.

First ResponseIs it true that some plug-ins do not support the multi-site mode, especially some cache plug-ins. But do not doubt these plug-ins for the time being. These plug-ins are very mature and do not have time to study their code for the reason. First, you need to find out the cause first.

 

 

Because some updates are also made to the ubuntu system when you change the wordpress configuration, you should first check whether there are any abnormal services or some special ports.

 

 

The log is indeed a little big, but it is not as big as it is, then a manual split is executed immediately. Logrotate-vf/etc/logrotate. conf

222.85.131.142--[12/Jul/2013: 14: 11: 30 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.088 0.088-222.85.131.142---[12/Jul/2013: 14: 11: 31 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.104 0.104-221.233.53.238---[12/Jul/2013: 14: 11: 35 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.082 0.082-222.85.131.142---[12/Jul/2013: 14: 11: 37 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.090 0.090-222.85.131.142---[12/Jul/2013: 14: 11: 42 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.099 0.099-183.219.208.255---[12/Jul/2013: 14: 11: 45 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.117 0.117-222.85.131.142---[12/Jul/2013: 14: 11: 46 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy) "-0.116 0.116-221.233.53.238---[12/Jul/2013: 14: 11: 48 + 0800] "GET/wp-content/uploads/2013/07/IMG_0604.jpg HTTP/1.1" 404 31 "-" "null (FlipboardProxy/1.1; + http://flipboard.com/browserproxy)"-0.084 0.084-

)

The situation gradually becomes clear:

My cdn function is implemented in this way: Replace the URL of our website in the article with the cdn server. Before the site address configuration for http://www.main.com, the article in the picture links are http://www.main.com, I will now configure the main site address for the http://main.com, cdn power link replacement is only effective for the http://main.com, as a result, the images in previous articles do not have the cdn function. This is a tragedy.

But there is an episodeWhen I arrived at the company the next day, I found that I/O was still very high. Although it has dropped a lot from the previous one, I used the above method to find which files were read so frequently. After I checked the files, I found that the image above (IMG_0604) was quite large. I found it was from Flipboard, so I asked a colleague next to me to borrow his ipad and use Flipboard to read this article, but I don't know how to check the source link of the image on the ipad. As soon as I saw it, Flipboard was almost clear: I have prepared a special rss output for Flipboard, and rss has a very abnormal cache, it must have been Flipboard that cached this article without the cdn effect. It happened that this article was quite lively and introduced us with a large PV and increased our load.