I've been unable to successfully mount an ext4 formatted drive to any of my EC2 instances. All are running CentOS 5.6 (32 and 64-bit mix) all successfully yum upgraded from one of public RightScale AMIs (originally CentOS 5.4) with some of the Rightscale stuff edited/removed as needed.
The error is always when mounting:
# mount -t ext4 /dev/sdf /test mount: unknown filesystem type 'ext4'
I've tried installing the latest e2fsprogs and e4fsprogs packages (also compiled from the latest e4fsprogs release) and tried 'mke2fs -t ext4' and 'mke4fs' with the same error every time when mounting. Formatting to ext2 will always mount just fine.
Is there a boot time option I need to change or something missing from the Kernel I can verify or change?
FYI: I installed a local CentOS 5.6 virtualbox instance and can mount an ext4 drive just fine using the same commands, so my assumption is it's something with EC2 or the RightScale image I used to upgrade to CentOS 5.6.