UPDATE - Nov 18 - 11am - Most Lustre-based services are now resolved. Please let us know if you have any continuing issues: email@example.com.
UPDATE - Nov 18 - 10:45am - We have discovered the cause of the issue, and are working on resolving it.
We are having issues with the Lustre filesystem today. The servers are hanging, which is causing client mounts to fail on servers. Our systems team is looking into it. We'll post more details here and on Twitter as we have them.