We ran out of space on our "containers" SAN volume and our UNIX team extended the volume. After the reboot, none of the docker containers or images were available. docker ps -a and docker images both report zero entries. The /var/log/messages file complains about the mount points for the containers are not available and after checking, they are missing from /dev/mapper. This is redhat linux.
Are you sure that extending the SAN volume keeps the data as is and just grows the block device?
If so how does the device-mappe know about the changed SAN volume.
For Docker-EE the comaptiblity matrix states, that RHEL 7.5 only supportes the overlay2 storage driver. The support stops with RHEL7.4. Though, if you are on Docker-CE this is probably worth nothing, since your installation already is not supported by docker (as in: you can raise a support ticket @DockerInc.).