Node Agenda Scheduler Mongo errno: 20, code: 'EMFILE' - node.js

Question

I am running a node scheduler using agenda. It runs fine for around 30 minutes and then it starts displaying this error.
{ [Error: EMFILE, open 'log/scheduler.log'] errno: 20, code: 'EMFILE', path: 'log/scheduler.log' }
{ [Error: EMFILE, open 'log/scheduler.log'] errno: 20, code: 'EMFILE', path: 'log/scheduler.log' }
[Error: failed to connect to [localhost:27017]]
[Error: failed to connect to [localhost:27017]]
[Error: failed to connect to [localhost:27017]]
[Error: failed to connect to [localhost:27017]]
[Error: failed to connect to [localhost:27017]]
I am using node js with mongo db deployed on a EC2 instance.
The code I wrote is here:
https://github.com/kelvinblade/bluesky-scheduler2
Any help would be appreciated.

Answer 1

EMFILE occurs when too many file descriptors are open as there is limitation in an os for the number of descriptors to be opened by a process.
You can reset this restriction by editing this file
/etc/sysctl.conf
or a more graceful approach is to use some module that would take care and have a connectionpool to monitor over the opened file descriptors.
You may try node-graceful-fs or filequeue
Git source :
https://github.com/isaacs/node-graceful-fs
https://github.com/treygriffith/filequeue.git
Install apppropriate node modules by
npm install node-graceful-fs
or
npm install filequeue
and replace your fs from default to
var fs = require('graceful-fs')
or
var fs = new FileQueue(100);
Personally i feel filequeue is better queuing system.