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Enabling ENA on AWS Instances (KBA5533)




KBA# 5533



Delphix administrators who want to take advantage of the Enhanced Network Adapter (ENA) on their existing Delphix Engines in AWS, may need to take the required steps described in the AWS documenation to enable ENA support by setting the Instance Attribute for the VM instance, and then reboot the Delphix Engine.  The relevant AWS documentation can be found at:

AWS CLI modify-instance-attribute will be used to alter the ena-support flag:

--ena-support | --no-ena-support (structure)
Set to true to enable enhanced networking with ENA for the instance.
This option is supported only for HVM instances. Specifying this option with a PV instance can make it unreachable.

An example execution would be:

aws ec2 modify-instance-attribute --instance-id 1234567890abcdef0 --ena-support

To validate the configuration change (or generally to query ENA support):

aws ec2 describe-instances --instance-ids "<instance_id>" --query "Reservations[].Instances[].EnaSupport"




Newly created AWS VMs that are ENA-enabled should not need the above configuration as ENA should be enabled by default. This issue affects VMs that were either migrated from 5.3 (the ENA driver is not supported in versions older than 6.0) to 6.0+, or VMs that were backed by AWS instance types that didn't support ENA and the customer changed their instance type to one that supports it.

Additional AWS documentation for ENA can be found at:




The hyperlink above provides additional references to instance operating system commands for driver validation and configuration; as an appliance, any command references for the instance operating system will not be applicable to the Delphix Engine and will not be required, and the commands referenced are unavailable to Administrators (modinfo, yum update, etc).

Outside of the Engine reboot, no other actions are required for driver enablement in the Delphix operating system (DxOS) once ENA is enabled for the instance.


Applicable Delphix Versions

Click here to view the versions of the Delphix engine to which this article applies
Major Release All Sub Releases


Only the AWS administrator can resolve this by enabling ENA from the AWS settings/attributes and rebooting the engine (see overview above).

To verify the enablement of the driver, the Delphix Administrator can execute network performance tests before and after ENA is enabled, at which point network throughput should show improvements (results will vary by instance type and setup).  Alternatively, Delphix Support can review a support log bundle to confirm driver enablement.

To avoid unexpected disruption to target Environments, it is recommended to disable VDBs prior to the Engine reboot.


If no visible changes take effect, Delphix Support can be engaged to verify the ENA driver is being used by the Engine network interface(s).