Issue Unexpected Peak of memory

[SergioP122]

Hi there.
We're experiencing strange memory behavior on our system.

A few hours ago, our RAM usage started to grow linearly over time. Checked on Performance monitor.
The only resource affected is the Apache webserver. The rest of the services seem to be working fine.

1 week graphic:


1 day graphic:


As you can see on the image, since Tuesday 15 feb., the usage starts to grow linearly and when it reaches the top. (At 1.3GB), the OS seems to free resources to keep working. The other 2 mountains that you see, correspond with services restarts that I manually made to free resources. But as you can see, memory keeps increasing over time again and again.

The server is running a Moodle instance and the process that seems to be consuming the memory is php-fpm7.0. I provide a screenshot of the top command:


If I execute /etc/init.d/php1.0-fpm restart the system will free the memory and will start growing linearly again. Note that we haven't made any single modification on our server in 4 months. I also made sure that this is not a DDOS-like attack. Only a few requests were made on the server during this timelapse.

To provide a little more context, I realized a full Plesk Backup on Sunday. Idk if that is stucking a process or something that keeps spawning childs and filling the memory.

Any help or advice would bee more than welcome, thanks in advance!

 

[Bitpalast]

At first sight I'd say that a usage of 1 GB is the normal state while your "normal" usage of only 100 MB seems exceptionally low. For PHP-FPM it would not be an unusual behavior to grab some RAM. One PHP-FPM instance can service several different transactions. All in all: I would simply let it do what it does. After all, the RAM usage is quite low, so there should not be any need for action at this time.

 

[SergioP122]

Hi Peter, thank you for your quick response. I think your guess is right. After a few hours, the system went back to a stable status again. I'll let the server run without making any further modifications, I'll reply if I find something unusual.

Thanks again!