NSM 8.3 - "Too many connections"

[lubomir_cerny]

Hi.

After some time in production, I can see occasionally error "Too many connections" during health check.

What is default value and how can I change this ?

This is last NSM 8.3 Standalone install.

[d_aloy]

Hi Lubomir

Could you provide more details?

What's the health check test you are running?

What's the sensor model?

Regards

David

[lubomir_cerny]

It is not specific check test.

I run standard check tests and sometimes several tests run OK but then the rest of tests returns "SQL Error: Data source rejected establishment of connection, message from server: "Too many connections""

I can see this on E-Mail Server Connectivity, Slow Queries, Unused Custom IPS Policies and some other tests.

When I re-run the same test subset, all is OK and tests return expected values.

NSM is on VMware with 10GB NIC. Local DB on NSM is used.

[d_aloy]

Hi Lubomir

That message is telling you the MySQL database has more connection requests that is can support.

I'm not 100% on how the Mysql connections are set during the install, but here you have a couple of points you can check:

• CPU's of the server where NSM/Mysql is installed will affect the number of threads supported by Mysql (i.e. if you have 4 CPU it will support 4*2=8 threads.
• Also, when you installed the NSM, did you correctly configure the settings for the right number of sensors you have? The higher the number of sensors, the more connections will be required. Maybe you have installed more sensors lately and this is increasing the connections requests above the initially configured settings.
  • You could try re-running the NSM installer over the current installation and increase the number of sensors to be managed to the maximum and see if that make any difference.

If as you say, the health check works sometimes, you could also try running the checks when the manager is less busy: i.e. you don't have any scheduled reports/maintenance tasks running.

What is the reason why you are running this health checks? Do you observe any other problems?

Regards

David

[lubomir_cerny · Accepted solution]

Because there is MySQL under the NSM, DB connection can be changed in my.cnf file

# Edit NSM_INSTALL_PATH/MySQL/my.ini and locate section [mysqld] and modify/add
max_connections = 250


MySQL’s default configuration sets the maximum simultaneous connections to 100.

Note from MySQL doc: The maximum concurrent connection can be maximum range: 4,294,967,295.but please, be carefull setting huge value.

Also see the thread_concurrency

# Try number of CPU's*2 for thread_concurrency

thread_concurrency=8

[ciaranr]

This one has been bugging me for a while - glad to see a solution to it!