>> Why would they implement their own client? Did they have to do something special in their client to
>> make it safe?
>
> I think it is mostly a performance issue. Each backend mounts its own copy
> of the data files it needs.
I personally would never put PostgreSQL on an NFS share on Linux.
Unless things have changed radically in the last couple years, Linux's
NFS code is flaky and unreliable, including flat-out lying about whether
stuff has been sent and received or not. This is why NetApp's NFS
servers came with their own, proprietary, Linux kernel module.
NFS on Solaris/Illumos is a different story. Not sure about FreeBSD.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com