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Re: htree stabilitity and performance issues

On Thu, Dec 18, 2003 at 01:36:25PM +1100, Adam Cassar wrote:
> What's your take on the nfs client load issues? It does run for 4-5
> hours albeit at higher load (how explained by your post) however it does
> eventually die with the load going stupid (180 odd). It seems that the
> patch still has some nfs interoperability problems.

Was this on the nfs *client* or the nfs *server*?  

I'd really, really like to see a ps listing on the machine involved;
the output of "ps alxww" and "ps auxww" would be useful.  The question
is what processes are hung in wait, and what they're waiting on....

It would also be interesting to see if the LD_PRELOAD hack which I
sent you helped alleviate the load on the server?  With the LD_PRELOAD
hack, the access pattern on stat's and open's should be restored to
the original workload, so if that makes the problem go away, then
the problem was merely that NFS doesn't degrade gracefully under load.

(This is not actually earth-shattering news; I've had really strange
results trying to do heavy-duty NFS over a wireless connection,
although that's more due to Linux's NFS implementation utterly failing
to deal dropped packets.)

I believe, although I am not sure, that there are some NFS
improvements that went into 2.6 that didn't get back-ported to 2.4.
So it might be that running 2.6.0 on the clients and/or servers might
actually help.  That would be a pretty daring move, though....

Finally, can you give me a little bit more detail of exactly what is
running on the clients and server, and the rationale of why you are
trying to apparently run incoming mail processes over NFS?  (Is that
what you're doing?  If so, it sounds rather scary...)

					- Ted

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