Completing the Offline Resizing Operation for Boot Volumes

After resizing the online block volume or boot volume, you need to perform the following administrative tasks.

Attach the boot volume to a second instance as a data volume.

See Attaching a Volume.
Extend the partition and grow the file system.

For details, consult the OS documentation for the OS type and version running in the instance.
Detach the data volume.

See Detaching a Block Volume.
Reattach the boot volume.

See Reattaching a Boot Volume.
Restart the instance.

See Stopping, Starting, and Resetting an Instance.