Troubleshooting AMI and kernel issues

Following, you can find information about troubleshooting issues related to certain Amazon Machine Image (AMI) or kernel versions when using Amazon EFS from an Amazon EC2 instance.

Unable to chown

You're unable to change the ownership of a file/directory using the Linux chown command.

Kernel versions with this bug

2.6.32

Action to take

You can resolve this error by doing the following:

• If you're performing chown for the one-time setup step necessary to change ownership of the EFS root directory, you can run the chown command from an instance running a newer kernel. For example, use the newest version of Amazon Linux.

• If chown is part of your production work flow, you must update the kernel version to use chown.

File system keeps performing operations repeatedly due to client bug

A file system gets stuck performing repeated operations due to a client bug.

Action to take

Update the client software to the latest version.

Deadlocked client

A client becomes deadlocked.

Kernel versions with this bug

• CentOS-7 with kernel Linux 3.10.0-229.20.1.el7.x86_64

• Ubuntu 15.10 with kernel Linux 4.2.0-18-generic

Action to take

Do one of the following:

• Upgrade to a newer kernel version. For CentOS-7, kernel version Linux 3.10.0-327 or later contains the fix.

• Downgrade to an older kernel version.

Listing files in a large directory takes a long time

This can happen if the directory is changing while your NFS client iterates through the directory to finish the list operation. Whenever the NFS client notices that the contents of the directory changed during this iteration, the NFS client restarts iterating from the beginning. As a result, the ls command can take a long time to complete for a large directory with frequently changing files.

Kernel versions with this bug

CentOS and RHEL kernel versions lower than 2.6.32-696.el6

Action to take

To resolve this issue, upgrade to a newer kernel version.