Page History

...

• Scaling NMIS Polling
• Scaling NMIS polling - how NMIS handles long running processes
• Configuration Options for Server Performance Tuning

Configuration items

NMIS runs a daemon to periodically obtain periodically the nodes information, and other maintenance jobs that need to be done (to calculate metrics, cleanup jobs, run the plugins, etc.). 

The main process - the nmis scheduler - runs a loop and checks which jobs need to be done. It will add these jobs into a queue, and it will fork worker processes that will run these jobs. 

The number of workers is set in the parameter nmisd_max_workers:

nmisd_max_workers

By default 10. 

This means the maximum number of worker processes that the nmis main process will be able to start.

This parameter takes by default a value of 10. But this value is too big for a small network. Can be adjusted based on the number of nodesSome aprox. configurations:

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

The nmis scheduler will run in a loop. When an iteration is finalised, the process will sleep for nmisd_scheduler_cycle seconds. This value is 10 by default, but it can be modified. 

'nmisd_scheduler_cycle' => 10,

There are a couple of configuration items to modify the lifecycle of the forks. 

'nmisd_worker_cycle' => 30,
'nmisd_worker_max_cycles' => 100,

nmisd_worker_cycle is the number of seconds the process will sleep if it doesn't have any job to perform. 

Every time a worker performs a job, a cycle counter is increased. It is possible to change the default behaviour so the worker is killed every N cycles. Another process will be started by the parent once the child process reaches the max cycles, if the number of children processes doesn't reach the max_workers. It will prevent a worker memory get too big. This number can be adjusted, as, if it is too low, there is a cost associated in killing and starting a new process. Can be changed in nmisd_worker_max_cycles. Check

Go to usr/local/nmis9/conf/ Config.nmis

Image AddedHere 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