Deprecate NFS support for Git storage

With the upcoming release of %13.0 in the next month, the Gitaly will have created a eventual consistent and eventually consistent layer through Praefect. This it one of the main reasons customers and the wider community uses NFS.

However, NFS is not without it's own faults. GitLab now supports NFS through our amazing support team, and in Gitaly itself there's multiple hacks to provide better NFS support, but are essentially not required to run on gitlab.com, or any of our non-NFS installs.

Further details

In addition to the Gitaly HA MVC, we are already working on:

strong consistency &1189 (closed)
distributing reads across replicas &2013 (closed)

This covers the primary NFS use cases.

Proposal

Deprecate support officially in %13.0
Remove/Drop support for NFS in %14.0

Additionally, provide a long time to transition for our customers.

Edited May 08, 2020 by James Ramsay (ex-GitLab)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information