|
Karl Kopper wrote:
>
> Hi Joe,
Hi Karl,
I don't see a copy of this to the mailing list, but I'm going to
reply there because of my policy of keeping technical discussions on the list
http://www.linuxvirtualserver.org/Joseph.Mack/HOWTO/LVS-HOWTO.introduction.html#getting_technical_help
> What about NFS?
NFS is fine to maintain state on LVS backends.
> I saw awhile back that the LVS FAQ said "NFS for clusters is
> dead."
not quite; a quote from the beowulf mailing list, referring to
the use of NFS in beowulfs says "NFS for clusters is dead".
I agree with this, but a beowulf is not an LVS. The reasons
why NFS does not work well in a beowulf (file propagation
scales with O(n) rather than something better like O(logn),
and is network intensive), should be used as cautions when
designing an LVS. In an LVS, if NFS is propagating read-mostly
files to the realservers where they will be cached and where
writes are not particularly time sensitive, then network traffic
will be much less and NFS is fine.
The other problem with NFS is that you have to handle the connection
to realservers which have just died.
> But my book, and the cluster I built is based on NFS as the CFS. I'm
> not a DB guy, but as I understand it Oracle's 9i RAC product is based on
> running Oracle servers on NFS clients with a NAS backend. Their strategy is
> to get all of their customers to move to the RAC line.
Oracle's goal is to make money for Oracle. I wouldn't regard
anything Oracle did at the technical level as a pointer to good
techical practice. It might be, but I would have to go elsewhere
to find out.
> Why the harsh treatment of NFS in the FAQ?
I just say that you shouldn't use NFS where it doesn't work.
Joe
--
Joseph Mack PhD, High Performance Computing & Scientific Visualization
SAIC, Supporting the EPA Research Triangle Park, NC 919-541-0007
Federal Contact - John B. Smith 919-541-1087 - smith.johnb@xxxxxxx
|
