I am running Wordpress on Apache server with Ubuntu 18 LTS
I have received an intermittent Error 521 on my website this morning when previewing a post. Following this the whole site was down (521 host down).
I checked my Apache2 error log and the only thing in the log is this, from several hours before:
[Tue Jul 09 06:25:40.040855 2019] [mpm_prefork:notice] [pid 995] AH00163: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.0g configured – resuming normal operations
[Tue Jul 09 06:25:40.040884 2019] [core:notice] [pid 995] AH00094: Command line: ‘/usr/sbin/apache2’
There is also nothing in the MySQL error log problem related.
Is there anywhere else I can check that could explain why the site went down? I rebooted and it is back up now.
Swap: around 200MB out of 1GB pool
CPU was fine, no more than 20%
Memory also fine probably around 60% including cache / buffers