[Samba] Aplication slow after migration

[Scott Lovenberg]

On Feb 6, 2008 4:19 AM, Felipe Martinez Hermo <felipe at galicia.ugt.org>
wrote:

>
>
> Sinisa Bandin escribió:
> >
> >
> > Felipe Martinez Hermo wrote:
> >>
> >>>> OK, so we're apples to apples, so to speak; the servers are tuned
> >>>> the same.  I'll assume your disks are tuned from hdparm and up to
> >>>> snuff, otherwise you wouldn't be tuning sockets ;).  Did your old
> >>>> server have samba settings for oplocks set?
> >>>>
> >>>>
> >>>> --
> >>>> Peace and Blessings,
> >>>> -Scott.
> >>>>
> >>>> "Of course, that's just my opinion; I could be wrong"
> >>>> -Dennis Miller
> >>> Erm, sorry, I didn't catch that you had 2 .conf files there.  I'm
> >>> back to the drawing board.  Sorry about that.  Anyone else have any
> >>> ideas?
> >> Yes, that's whats shocking me. Apparently we're apples to apples.
> >> Except for the kernel (new&slow 2.6.18-4-686 vs old&fast 2.6.8)
> >>
> >> I've sniffed both eth0 interfaces and I've got some more information.
> >> When talking to the slow server, the client needs to send 76 "TCP
> >> segment of a reassembled PDU" that are not sent when talking to the
> >> old and fast server.
> >>
> >> How can I workaround this issue? Should I lower server's MTU? How much?
> >>
> >> Thank you
> > Do you happen to have a Realtek 8169 based gigabit ethernet in new
> > server?
> >
> > If you do, I had the same problem several times last year, and solved
> > all of them by changing motherboards (all were integrated, and I like
> > them to stay that way because I can achieve full gigabit speed with
> > several concurent clients)
> >
> > Best regards,
> > Sinisa Bandin
> >
> >
>
> No, machines are out-of-the-box HP DL servers:
> Ethernet controller: Broadcom Corporation NetXtreme BCM5705_2 Gigabit
> Ethernet (rev 03)
>
> I've made a spreadsheet with summarizing wireshark results and comparing
> results for both servers. You can see it here:
> http://spreadsheets.google.com/ccc?key=pnLL2fInqFq2YKuZIphtQdA
>
> It's meaningful that fast server makes 406 Trans2 calls, while slow
> server makes 616 calls to perform the same operation. The difference is
> mainly in QUERY_PATH_INFO (200 vs 305) and FIND_FIRST2 (94 vs 199) calls.
>
> Next try: change ethernet wire?  :-?
>
>
> --
> ==============================
> Felipe Martínez Hermo
> felipe at galicia.ugt.org
> fmartinez at galicia.ugt.org
> ==============================
> Servicios Informáticos
> UGT Galicia
> informatica at galicia.ugt.org
> ugtgalicia at gmail.com
> ==============================
> --
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Hrm, are you using SACKs or DSACKs or tcp_low_delay in
/proc/sys/net/somethingOrOther?  They didn't change congestion control
default in your upstream kernel, did they?  Should be "reno" by default.
Doing a netstat -a, do you have many packets queued in either direction?
This one is puzzling me.

-- 
Peace and Blessings,
-Scott.