Page Comparison

There are lots of factors that determine the system health of a server. The hardware capabilities - CPU, memory or disk - is an important one, but also the server load - number of devices (Nodes to be polled, updated, audited, synchronised), number of products (NMIS, OAE, opCharts, opHA - each running different processes), number of concurrent users. 

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omkd_max_requests

MongoDB memory usage

MongoDB, in its default configuration, will use will use the larger of either 256 MB or ½ of (ram – 1 GB) for its cache size.

MongoDB cache size can be changed by adding the cacheSizeGB argument to the /etc/mongod.conf configuration file, as shown below.

storage:
  dbPath: /var/lib/mongodb
  journal:
    enabled: true
  wiredTiger:
      engineConfig:
         cacheSizeGB: 1

Here is an interesting information regarding how MongoDB reserves memory for internal cache and WiredTiger, the underneath technology. Also some adjustment that can be done: https://dba.stackexchange.com/questions/148395/mongodb-using-too-much-memory

Server examples

Stressed system 

Status
colour Green title poller-nine

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This is how the server memory graphs looks in a stressed system - We will be focused on the memory as it is where the bottleneck is: 

NMIS process keeps stable, is not using more than 120 mb, and the process was stopped - probably killed for the system due to high memory usage: 

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And mongod keeps using a lot of memory - 3GB, as configured - but it is stable:

Normal system

This is Check processes once nmis9d is restarted again:

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Image Added

Normal system 

Status
colour Green title master-nine

System information:

This is how the server memory graphs looks in a normal system: