We are in the process of upgrading our NFS storage. To do this, we'll need to make home directories read-only for a few minutes on Sunday afternoon, then once again late Sunday evening.
We anticipate the read-only mode to last only about 15 minutes, but there may be an additional 5-10 minutes of full downtime while we transition into it.
Most websites should continue to work during read-only mode. SSH will continue to work, but with limited capabilities.