[Samba] Aplication slow after migration
Felipe Martinez Hermo
felipe at galicia.ugt.org
Thu Feb 7 10:33:23 GMT 2008
Scott Lovenberg escribió:
> On Feb 6, 2008 4:19 AM, Felipe Martinez Hermo <felipe at galicia.ugt.org
> <mailto: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
> >> 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
> > all of them by changing motherboards (all were integrated, and I
> > 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
> results for both servers. You can see it here:
> 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)
> Next try: change ethernet wire? :-?
> Felipe Martínez Hermo
> felipe at galicia.ugt.org <mailto:felipe at galicia.ugt.org>
> fmartinez at galicia.ugt.org <mailto:fmartinez at galicia.ugt.org>
> Servicios Informáticos
> UGT Galicia
> informatica at galicia.ugt.org <mailto:informatica at galicia.ugt.org>
> ugtgalicia at gmail.com <mailto: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,
Apparently everything is configured the same way in /proc/sys/net (both
sack & dsack = 1). Regarding the kernel, Old&fast kernel is 2.6.8 (no
/proc/sys/net/ipv4/tcp_congestion_control) while new&slow is
2.6.18-4-686 and congestion control is bic:
ugtgalicia at max:~$ cat /proc/sys/net/ipv4/tcp_congestion_control
Should I try other congestion control algorithm?
I've made this rudimentary test, and old server is a little bit faster,
but I don't know if it is meaningful at all.
felipe at nils:~$ ping -i 0.2 fast_server
--- fast_server ping statistics ---
2156 packets transmitted, 2156 received, 0% packet loss, time 431208ms
rtt min/avg/max/mdev = 0.135/0.171/0.245/0.018 ms
felipe at nils:~$ ping -i 0.2 slow_server
--- slow_server ping statistics ---
2146 packets transmitted, 2146 received, 0% packet loss, time 429165ms
rtt min/avg/max/mdev = 0.152/0.179/0.333/0.021 ms
Felipe Martínez Hermo
felipe at galicia.ugt.org
fmartinez at galicia.ugt.org
informatica at galicia.ugt.org
ugtgalicia at gmail.com
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