Sidebar to Apple OS X SMB issues across VPN

[David Collier-Brown]

  Hmmn, with the new ethereal reporting on per-type
response times, could you get a capture of a
client doing the same operations to a linux server?
  We could then look at the comparative getfirst/getnext
times.

--dave

David Collier-Brown wrote:
>  There are often two settings that give good speed: just
> small enough to fit into an MTU, and really, really big.
> 
>  The former gets efficiencies if fragmentation and
> errors cause retransmissions, but it assumes the application
> can process many small reads/writes quickly.
> 
>  The latter gets efficiencies if the application
> works best with few large writes, but assumes the
> IP stack will do the packetization elegantly.
> 
>  You're using the latter, which often works well
> with samba. I'd try unsetting the "Ignore DF (Don't Fragment)
> Bit" at the offsite end and see if it has an effect. Mismatching them is 
> probably not good.
> 
> --dave
> 
> 
> 
> Dan Tappin wrote:
> 
>> My brain hurts after reading this :)...
>>
>> Being that this my system being dissected I will add some comments.
>>
>> I played with the:
>>
>>  - Xserve's MTU (currently 1492 - default 1500)
>>  - the Xserve's Sonicwall's MTU (1500)
>>
>> Here is the options from the Sonicwall's ethernet config page:
>>
>>  - (checked) Fragment non-VPN outbound packets larger than WAN MTU
>>  - (not checked) Ignore DF (Don't Fragment) Bit
>>  - WAN MTU: 1500
>>
>> hmmm... I just double checked the offsite's Sonicwall:
>>
>>  - (checked) Fragment non-VPN outbound packets larger than WAN MTU
>>  - (checked) Ignore DF (Don't Fragment) Bit
>>  - WAN MTU: 1500
>>
>> So if one device is passing unfragmented data and the other is  
>> fragmenting it any way (remember I know nothing about TCP/IP -  
>> forgive my ignorance) could this be the issue?
>>
>> I have made both the same (not checked).  I will double check the  
>> speed issue and then also try both checked.  Before I do any  
>> suggestions as to which one would be better?  Same goes for a MTU  
>> setting?
>>
>> Dan T
>>
>> On Oct 24, 2005, at 2:56 PM, Christopher R. Hertel wrote:
>>
>>> Dave,
>>>
>>> The continuation messages occur whenever the SMB message is larger  than
>>> the MTU on the link.  It's the TCP/IP stack that breaks the large  
>>> SMB down
>>> into smaller chunks for transmission.
>>
>>
>>
>> <<snip>>
>>
> 

-- 
David Collier-Brown,      | Always do right. This will gratify
Sun Microsystems, Toronto | some people and astonish the rest
davecb at canada.sun.com     |                      -- Mark Twain
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