I have quite odd problem which i had for quite a time. I'm using powerful OVH dedicated server and i'm not sure what exactly is a root issue here.
I've migrated out of Cloudflare cdn, so this problem is quite annoying now and i need to finally tackle it. I have noticed that from time to time my server, randomly timeout connections. What i'm using:
- Nginx and hosting aprox ~15servers/domains via domains only.
- HHVM for some servers in Nginx, PHP-FPM for others
- Ubuntu 16.04.x
What i have noticed about issue:
- It does really happen randomly, sometimes timeout is longer 2-4min, sometimes few sec only. Sometimes it's limited to secluded cases, rarely, at least once per day for longer period for ~5-15s for more than 10 independent locations. It's possible that it won't happen for an hour, but it can happen many times in short period of time as well.
- At time of issue i still have active connection ssh connection to server and ICMP ping to server, both working fine - however httping fails at time of issue
- I haven't noticed any error logs in Nginx error.log
tail -f error.logi thought that maybe proxy to hhvm/php-fpm fails, but there is no gateway issues whatsoever, neither php execution engines nor database is loaded heavily to cause any issue whatsoever.
- At time of issue, there are no logs appearing from "broken" ip which is connecting at time in nginx access.log
tail -f access.log | grep "126.96.36.199"
I would really, highly appreciate any input to where look for to solve this as i'm out of ideas.