Overview
Opmantek gets many questions on how to scale NMIS8 for very large networks. There are many factors impacting polling performance and the upper limits of polling is really only limited by the number of processor cores, available memory and disk IO performance. We have customers managing 10's of 1000's of nodes using NMIS.
| Table of Contents |
|---|
Related Articles
- Scaling NMIS polling - how NMIS handles long running processes
- Configuration Options for Server Performance Tuning
Server Specifications
Storage performance is one of the greatest factors for scaling polling, you should consider using highly performant storage like SSD.
| Small | Medium | Large | Massive | |
|---|---|---|---|---|
| OS Storage | 20GB | 20GB | 20GB | 20GB |
| Data Storage | 40GB | 60GB | 140GB | 280GB |
| Memory |
| 4GB |
| 8GB |
| 16GB |
| 32GB+ | ||
| CPU | 2 x vCPU | 2 to 4 x vCPU |
| 8 x vCPU |
| 16+ vCPU | ||||
| Device Count | < 500 devices | < 1500 devices | < 2500 devices | A very large |
| Element Count | 2000 elements | 8000 elements | 14000 elements | A very large number of elements |
Elements are additional data being collected, an interface is an element, a CBQoS class is an element.
An element requires additional SNMP polling to collect the values and then storage on the disk to save the data.
...
To The best thing to do if If you want to do this, is to stop the polling , run an update cycleThe most likely root cause here is just too much going on when you add all 2000 devices. When you add nodes and and then run an update and cycle, then a collect , it creates LOTS of RRD files, so the disk IO is at a peak during this process.
Configuration Considerations
...
cycle manually, then start the polling.
To stop polling modify the configuration option global_collect to false or stopping polling in the crontab, comment out this line:
| Code Block |
|---|
#*/5 * * * * /usr/local/nmis8/bin/nmis.pl type=collect mthread=true maxthreads=8 |
Then add nodes, all of them at once or in batches. Restart fpingd so that it reloads all the nodes you added.
| Code Block |
|---|
/usr/local/nmis8/bin/fpingd.pl restart=true |
Then run an update manually with nohup, if you have 12GB of memory you can give it lots of threads, probably 20 should do it, but watch your memory usage you can probably get to 30 threads.
| Code Block |
|---|
cd ~ |
...
nohup /usr/local/nmis8/bin/nmis.pl type=update mthread=true maxthreads=20& |
This will take a while to run the first time, when it finishes, run a collect cycle the same way
| Code Block |
|---|
nohup /usr/local/nmis8/bin/nmis.pl type=collect mthread=true maxthreads=20& |
Now all the big disk activity is done and you should be able to start NMIS polling by letting the poller go again.
| Code Block |
|---|
*/5 * * * * /usr/local/nmis8/bin/nmis.pl type=collect mthread=true maxthreads=<MAX THREADS BASED ON YOU BASELINE> |
Configuration Considerations
| Code Block |
|---|
*/2 * * * * /usr/local/nmis8/bin/nmis.pl type=summary |
4-59/5 * * * * /usr/local/nmis8/bin/nmis.pl type=threshold |
In Config.nmis:
| Code Block |
|---|
'threshold_poll_cycle' => 'false', |
...
'nmis_summary_poll_cycle' => 'false', 'disable_interfaces_summary' => 'true', |
The other BIG consideration is what is your polling policy
...
, the more interfaces you collect on, the more disk, cpu and memory you will consume,
...
just collecting more data may not help you operationally, collect the right data, which is how NMIS has been configured.
If you hare having problems scaling your NMIS installation, you could contact Opmantek for assistance.
Using JSON for NMIS Database
To optimise how NMIS files are saved, you can use the JSON database, this will require NMIS 8.4.8g or greater. The following needs to be run on every Primary and poller server in an NMIS cluster and this should be co-ordinated to run very close together.
| Code Block |
|---|
/usr/local/nmis8/admin/convert_nmis_db.pl |
This script will stop NMIS polling, convert the database files, update the NMIS configuration to use the new database format, then start the polling again.