Re: Performance of PostgreSQL over NFS

Mladen Gogala wrote:
> Rich wrote:
>> I am wondering why anyone would do that? Too much overhead and no
>> reliable enough.
>
> Apparently, NetApp thinks that it is reliable. They're selling that
> stuff for years. I know that Oracle works with NetApp, they even
> have their own user mode NFS client driver, I am not sure about
> PostgreSQL. Did anybody try that?
>

You have hit upon the crucial distinction here. In order for NFS to
work well, you need a rock solid NFS server. NetApp does a good job
there. You also need a rock solid NFS client, configured perfectly in
order to eliminate the risk of corruption you get if the NFS
implementation makes any mistake in handling sync operations or error
handling. The issue really isn't "will PostgreSQL performance well over
NFS?". The real concern is "will my data get corrupted if my NFS client
misbehaves, and how likely is that to happen?" That problem is scary
enough that whether or not the performance is good is secondary. And
unlike Oracle, there hasn't been much full end to end integration to
certify the reliability of PostgreSQL in this context, the way
NetApp+Oracle has worked out those issues. It's hard to most of us to
even justify that investigation, given that NFS and NetApp's offerings
that use it feel like legacy technologies, ones that are less relevant
every year.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services and Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books