My website gets stuck for few seconds, before starting to work again

[bhanusingh]

I am running a website on OpenLiteSpeed Server with Digital Ocean.
The configuration of my droplet is:

4 GB Memory
80 GB Disk
OpenLiteSpeed WordPress 5.6 on Ubuntu 20.04

Sometime my website takes a long 3-4 seconds to respond to a request. Recently this has become very common and it is occurring very frequently.
To investigate the issue, I checked Logs to find the following.

From stderr.log

2021-01-14 05:29:49.994 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.094 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.194 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.294 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.395 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.495 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.595 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.695 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.795 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.896 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:50.996 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.096 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.196 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.296 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.396 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.496 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.597 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.697 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.797 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.897 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.997 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.097 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.197 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.298 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.398 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.498 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.598 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.698 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.

From error.log

2021-01-14 06:03:50.037986 [NOTICE] [111.11.111.!:52950-Q:71B8448DC86D8853-9#wordpress] No request delivery notification has been received from LSAPI application, possible dead lock.
2021-01-14 06:03:50.038014 [NOTICE] [111.11.111.1:60056#wordpress] No request delivery notification has been received from LSAPI application, possible dead lock.
2021-01-14 06:03:50.038034 [NOTICE] [111.11.111.1.109:45606-Q:2707992EDC0AB4D1-117#wordpress] No request delivery notification has been received from LSAPI application, possible dead lock.
2021-01-14 06:03:54.031122 [NOTICE] [111.11.111.1.109:45606-Q:2707992EDC0AB4D1-121#wordpress] No request delivery notification has been received from LSAPI application, possible dead lock.

There are lots of logs like this. (Changed the IP value)

Every other configuration on the instance is default except, memory_limit = 512M.

Does these logs tell anything about why my website is getting stuck ?

 

[Cold-Egg]

Hi,
According to the error log "Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN." that your server has hit the limit, please go to WebAdmin console > Server Configuration > External App > lSPHP7x, update both Max Connections and LSAPI_CHILDREN from 10 to a higher number, e.g. 30. Let us know if it works.

 

[bhanusingh]

Hey @Cold-Egg I have made the changes suggested by you. Will keep a check and let you know if the issues doesn't solve.

Thanks!

 

[bhanusingh]

Hey @Cold-Egg I said as you asked but I still see the same errors.

2021-01-14 05:29:51.797 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.897 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:51.997 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.097 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.197 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.298 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.398 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.498 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.598 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.
2021-01-14 05:29:52.698 [STDERR] [171231] Reached max children process limit: 10, extra: 0, current: 10, busy: 10, please increase LSAPI_CHILDREN.

I have attached the changes you suggested and did a graceful restart. It still doesn't reflect in my error.

Am I doing something wrong ?

 

[Cold-Egg]

I guess it still happens due to OpenLiteSpeed comes with php detached mode by default, so need to restart php with command killall -9 lsphp to make settings take effect. If it still not work, please raise a ticket to support@litespeedtech.com

 

[bhanusingh]

Hey @Cold-Egg, I was able to get it work. The issue has been resolved.

I do have some question around it though.

What exactly are those that I changed ? And does one come up with a number. Like 30 ? Is there any resource around this that I can read or any formula which would determine this.

Thanks!