Just a guess but...any chance you have BCM NICs?
7. nov. 2014 00:09 skrev "Adam Thompson" <[email protected]> følgende:

> Well, that would definitely cause a problem if it were the case, but...
> 1) TCP window size != MTU,
> 2) all switches and Router (but not pfSense) can both handle 9000-byte
> frames anyway,
> 3) MTU on server and client are both standard, at 1514,
> 4) I can confirm no fragmentation is occurring.
>
> Still don't know why performance is so bad, though.
>
> -Adam
>
>
> On November 6, 2014 4:58:35 PM CST, Sean <[email protected]> wrote:
>>
>> Not a TCP expert but the MTU is nearly always 1500 (or just under) hence
>> your limit.  Sending packets greater than the MTU will lead to
>> fragmentation.  Fragmentation leads to re-transmissions (depends on do not
>> fragment bit?) and performance problems.  Performance problems leads to
>> frustration and anger.  Anger leads to the dark side of the force.
>>
>> You can increase the MTU to like 9000 or something if you enable jumbo
>> frames but you'd need to support it across the board (pfSense, routers,
>> switches?, servers, etc.).  It's a hassle probably not worth the effort in
>> terms of gains.  Some people do it as a means to increase iSCSI traffic
>> performance but others say the throughput gain is dubious at best.  I would
>> make sure some doofus didn't enable jumbo frames on your NFS server and if
>> so then turn it off and check the MTU setting in the network stack on the
>> NFS server as well.
>>
>> I may not know what the hell i'm talking about though so someone else can
>> feel free to jump in and tell me what an idiot I am.
>>
>>
>>
>> On Wed, Nov 5, 2014 at 6:47 PM, Adam Thompson <[email protected]>
>> wrote:
>>
>>> Problem: really, really bad performance (<10Mbps) on both NFS (both tcp
>>> and udp) and CIFS through pfSense.
>>>
>>> Proximate cause: running a packet capture on the Client shows one
>>> smoking gun - the TCP window size on packets sent from the client is always
>>> ~1444 bytes.  Packets arriving from the server show a TCP window size of
>>> ~32k.
>>>
>>>
>>> The Network:
>>>                     +------+
>>>                     |Router|
>>>                     +--+---+
>>>                        |
>>>                 --+----+----+--
>>>                   |         |
>>>                +--+---+  +-------+
>>>                |Client|  |pfSense|
>>>                +------+  +--+----+
>>>                             |
>>>                           --+---+--
>>>                                 |
>>>                              +--+---+
>>>                              |Server|
>>>                              +------+
>>>
>>>     - Client and pfSense both have Router as default gateway.
>>>     - pfSense has custom outbound NAT rules preventing NAT between
>>> Server subnet and Client subnet, but NAT'ing all other     - outbound
>>> connections.
>>>     - Router has static route pointing to Server subnet via pfSense.
>>>
>>> Hardware:
>>>     Router is an OpenBSD system (a CARP cluster, actually) running on
>>> silly-overpowered hardware.
>>>     Client is actually multiple systems, ranging from laptops to
>>> high-end servers.
>>>     Server is a Xeon E3-1230v3 running Linux, exporting a filesystem via
>>> both NFS (v2, v3 & v4) and CIFS (samba).
>>>     pfSense is v2.1.5 (i386) on a dual P-III 1.1GHz, CPU usage typically
>>> peaks at around 5%.
>>>
>>>
>>> Performance on local Server subnet (i.e. from a same-subnet client) is
>>> very good on all protocols, nearly saturating the gigabit link.
>>> Traffic outbound from the server subnet to the internet (via Router)
>>> moves at a decent pace, this firewall can typically handle ~400Mbps without
>>> any trouble, IIRC synthetic benchmarks previously showed it can peak at
>>> over 800Mbps.
>>>
>>> Based on the FUBAR TCP window sizes I've observed, I assume pfSense is
>>> doing something to my TCP connections... but why are only the non-NAT'd
>>> connections affected?  I know there's an option to disable pf scrub, but
>>> that's only supposed to affect NFSv3 (AFAIK), and this also affects
>>> NFSv4-over-TCP and CIFS.
>>>
>>> --
>>> -Adam Thompson
>>>  [email protected]
>>>
>>> _______________________________________________
>>> List mailing list
>>> [email protected]
>>> https://lists.pfsense.org/mailman/listinfo/list
>>>
>>
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> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
>
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