@Mholloway do you know about this one?

For some reason, on deployment-maps04, it seems /var/lib/postgresql/9.6/main is being treated as the data directory rather than /srv/postgresql/9.6/main, even though the latter is set in postgresql.conf. Need to investigate further to figure out why that is.

That's probably a good thing to look into though be careful as /srv has it's own problems:
/dev/mapper/vd-second--local--disk 60G 49G 7.5G 87% /srv

Mentioned in SAL (#wikimedia-releng) [2018-07-30T20:57:58Z] <mdholloway> deployment-maps04 restarted postgresql to pick up the correct data_directory value (T200634)