Running MongoDB in the Cloud

  • by Dan Crosta, Software Engineer, 10gen
  • I know speaker from twitter and him answering questions about MongoDB to help me with


Late cause we were intercepted by Redhat/OpenShift marketing who wanted our advice on logos.

MongoDB components

  • Config Servers send config data to shards
  • Shards can run with the config server down, but it is not fun.

Replica Sets

Different methods of setup:

  1. The most popular

    • Primary
    • Secondary
    • Secondary
  2. Another way

    • Primary
    • Secondary
    • Arbiter
  3. The big option

    • Primary
    • Secondary
    • Secondary
    • Secondary
    • Secondary

Amazon EC2 Instance Types


Never deploy with 32-bit. Don’t do it!!!

  • Go for a Large or Extra-Large on-demand instance. More expensive but worth it.
  • ConfigD / Arbiter can be done via micro on demand instances

Operating System

  • Use ext4, xfs

  • Use RAID:

    • Raid 10 on MongoD
    • Raid1 on ConfigbDB
  • Turn off atime

    • File descriptor limits:

      cat >> /etc/security/limits.conf << EOF * hard nofile 65536 * soft nofile 65536 EOF