Site access Slow Latency high troubleshooting

Today around 9 o'clock in the morning, the mobile app received an email alert, opened a look, prompting an IP site access exception,

Try SSH connection and find it very slow. Unable to connect properly. Can be connected normally after a while, but the delay is very high, basically unable to operate.

Change SSH mode, through the same intranet other machines SSH login, found normal. PS: In fact, it should be possible to initially determine the problem is outside the network.

Top view, CPU, memory OK, netstat view the number of Web connections, concurrency of about 300. For apache+php+mysql sites, this concurrency is no pressure. Io is also normal.

Stop the HTTPD service and the network is back to normal. PS: In this judgment there is a problem, thought is httpd problem. And then wasted a lot of time on Apache. And did not find a trace of log related error records.

Open the httpd service, after a few seconds, the delay increased, the site is very slow to access, loading PHP completely.

PS: In this case, the miscalculation is the problem of PHP. In fact, PHP loading and reading related data are required to be relatively large bandwidth.

Try httpd not load PHP, delay normal.

It is here to keep in mind the relevant personnel of cloud provider Ustack. They gave the network a normal response when they asked Ustack to help them check their network.

Next, is the constant attempt. From a snapshot from a new host and switch IP past, or an exception.

PS: In fact, at this time basically ruled out the problems of the program and apache,php. Because the snapshot was just a snapshot from the normal machine the day before yesterday.

Behind, in the case of high site latency, through the Intranet Curl website, found to be normal state ... This concludes that there must be an issue with the extranet IP. Then use the Network window machine again to visit the Web site confirmation, intranet access all normal.

After the situation has been determined, and ustack personnel communication, still reply to us, the network is all right, please do your own troubleshooting.

The last few minutes, is to replace the external network IP, modify the DNS resolution, and so on after the resolution, access is normal.

PostScript: Positioning problems too slow, a little doubt their own judgment.

Site access Slow Latency high troubleshooting