How to make EC2 MTU Settings Compatible with Amazon Redshift, Part 2

 • Updated on 

TlDR: If you are using DHCP and you want to permanently set the MTU for your instance, edit your DHCP client config.

If you read our first article on setting the MTU on an EC2 instance for Amazon Redshift usage, then you may want to read this as well. After using the commands in the first article, we noticed that after some time, our instances had their MTU set back to 9001. We realized this was due to MTU settings being sent by the DHCP server since that is the default for these instances (C3, M3, etc). We then set out to edit all our Chef recipes to deploy our new DHCP client configuration files so we can quickly deploy them to all our instances.

Here is what should be added to the /etc/dhcp/dhclient.conf (on Ubuntu Precise LTS):

#added these two lines before the request line
default interface-mtu 1500; supersede interface-mtu 1500;

When adding this to the dhclient.conf file, it will override an MTU setting of 1500 to the interface that's set for DHCP. Hope this helps someone!

# About FlyData

FlyData Inc. formerly known as Hapyrus Inc., is a Dave McClure’s 500 Startups graduate, headquartered in Palo Alto, California. FlyData provides software that automates data replication to Amazon Redshift. If you'd like to simplify your BI analytics backend, let us know. Contact: FlyData, Inc support@flydata.com.

Worry-free replication from source to Redshift & Snowflake
Unlimited sync during trial
No credit-card required
World class support
Try FlyData for free
Amazon Partner Logo Certified AWS
Redshift partner
Get started. Try FlyData.
Quick setup. No credit card required. Unlimited sync during trial.
Fast and secure Enterprise-grade security and near real-time sync.
World-class support Proactive monitoring from technical experts, 24/7.
Straightforward pricing Pay for the rows you use, and nothing you don’t.