read/write multiplexed support
Marcel Müller
samba at maazl.de
Tue May 19 18:58:01 GMT 2009
Christopher R. Hertel wrote:
> It would also help to have the NegProt. Since the dialect is prior to NT LM
> 0.12 we won't see capabilities bits, but we will see whether the Raw Mode
> bits are set in the NegProt response.
I think you are right.
There are two scenarios.
1. The connection is slow from the beginning.
2. The connection is initially fast and slows down after a few hours.
In the second case there was always a timeout involved in some way. So I
think we can forget about that, since the timeouts are only reproducible
with a certain version of the IBM requester, which is not the most
recent one.
But I conclude from that, that the speed (and the transfer protocol)
does not change once the session is active.
But the first case is curious. I only have a vague guess. The disk in
the server might be down at when the client connects in the first time.
The spin up may take too long for some SMB request, again resulting in a
timeout. Unfortunately I was not able to reproduce this by stopping the
device explicitly with sdparm. But the data required at the session
setup may still be in the cache, when the disk is down. Furthermore it
is not that easy to do a tcp dump while the disk is down.
I now did some tweaks to the client configuration. In fact I disabled
the multiplex modes in the wrkheuristics setting. This should at least
force the differences between samba 3.0.x and samba 3.2.x to disappear.
Since that, I was not able to reproduce the problem with samba 3.2.5
with about 5 longer sessions. No Idea why. Maybe this happened only by
chance. Maybe the client takes the raw and the multiplexed modes coequal
and to disable one of them fixed it. This would also explain, why the
communication with windows servers is always fast, because they never
support both modes at once.
I will let you know if I have something new.
As far as I see the solution will be in the surrounding of the
negotiation, if any.
Btw, is it possible that the server still claims to support multiplexed
modes at negotiation?
Marcel
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