Mongo 7.0.15-9 and Release of Open Files

MongoDB Percona Server for MongoDB
1

Good morning,

Lately our percona instances are coming down a lot due to the TooManyOpenFiles error:

{“t”:{“$date”:“2025-07-18T10:00:25.806+02:00”},“s”:“E”, “c”:“NETWORK”, “id”:6328201, “ctx”:“conn670”,“msg”:“Unable to create eventfd object”,“attr”:{“error”:{“code”:264,“codeName”:“TooManyFilesOpen”,“errmsg”:“error in creating eventfd: Too many open files, errno: 24”}}}

or

{“t”:{“$date”:“2025-07-19T13:00:23.589+02:00”},“s”:“I”, “c”:“NETWORK”, “id”:23018, “ctx”:“listener”,“msg”:“Error accepting new connection on local endpoint”,“attr”:{“localEndpoint”:“0.0.0.0:20100”,“error”:“Too many open files”}}

We’ve noticed that this is happening mainly with version 7.0.15-9 with Ubuntu 22.04.5 LTS Operating System.

I’ve tried to see if there was some mention of this on the release notes and I don’t see anything related to open files on:

As anyone else have the same issue?

Regards,

André Ferreira

2

Hi, the OS default max open files is usually low for MongoDB. Have you increased it? typically for prod 64000 is the recommended number.

3

Yes, we’ve 204800 (or bigger) on all of our servers.

4

@afmf you might have to check specific to the mongod user/process:

  1. Check number of open files using lsof -u mongod
  2. Check the current limits for the mongod process
    1. pidof mongod
    2. cat /proc/<pid>/limits
  3. If the limit has reached, either:
    1. Increase ulimits in /etc/security/limits.conf and restart mongod
    2. Use connection pooling (if above not feasible)

Hope that helps.

Regards,

Ezhilan Ulaganathan