SuSE Linux Enterprise Server OpenSSH 5.1p1 nagle issue?

[Jeremy Guthrie]

I updated the client to the latest Openssh 6.1p1, and that made no 
difference.  I am still seeing the same problem.  I am going to try and 
update the server and see if it causes this to go away.

On 10/17/12 4:13 PM, Jeremy Guthrie wrote:
> I am able to reproduce this issue(randomly).  Everytime it happens, I 
> do see ssh keepalives show up.
>
> The command I ran:
> ssh -o "ServerAliveInterval 15" -o "ServerAliveCountMax 4" -o "Cipher 
> aes256-ctr" -v -v -v -v -v -v -v -v -v -v x.x.x.x ./test.pl
>
> If I run...
> ssh -o "ServerAliveInterval 15" -o "ServerAliveCountMax 4" -o "Cipher 
> aes256-ctr" -v -v -v -v -v -v -v -v -v -v x.x.x.x
> and type in no output.... I see ssh keepalives after ~ 15 seconds.  
> However, in this case, I ran it for six minutes(was an hour last 
> time), as soon as I see keep alive messages show up, my throughput tanks.
>
> On 10/17/12 3:50 PM, Jeremy Guthrie wrote:
>> I have another bit of detail, I think SSH keepalives are part of the 
>> issue.  This test didn't have me using the same values for keepalives 
>> that I use in production so I am going to re-conduct the test with 
>> matching SSH settings like in production.
>>
>> When things look good:
>> debug2: channel 0: window 1966046 sent adjust 131106
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1998272 sent adjust 98880
>> debug2: channel 0: window 1982464 sent adjust 114688
>> debug2: channel 0: rcvd ext data 36
>> Wed Oct 17 15:26:19 2012 0.004193
>> debug2: channel 0: written 36 to e
>> d 6
>> debug2: channel 0: window 1966044 sent adjust 131108
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1998272 sent adjust 98880
>> debug2: channel 0: window 1982464 sent adjust 114688
>> debug2: channel 0: rcvd ext data 36
>> Wed Oct 17 15:26:34 2012 0.004004
>> debug2: channel 0: written 36 to e
>>
>> When things are slow:
>> debug2: channel 0: window 1998812 sent adjust 98340
>> debug1: client_input_channel_req: channel 0 rtype 
>> keepalive at openssh.com reply 1
>> debug1: client_input_channel_req: channel 0 rtype 
>> keepalive at openssh.com reply 1
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug1: client_input_channel_req: channel 0 rtype 
>> keepalive at openssh.com reply 1
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug1: client_input_channel_req: channel 0 rtype 
>> keepalive at openssh.com reply 1
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug1: client_input_channel_req: channel 0 rtype 
>> keepalive at openssh.com reply 1
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug1: client_input_channel_req: channel 0 rtype 
>> keepalive at openssh.com reply 1
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: window 1966080 sent adjust 131072
>> debug2: channel 0: rcvd ext data 37
>> Wed Oct 17 15:30:21 2012 196.41162
>>
>>
>>
>


-- 
*Jeremy Guthrie*
Technical Architect - Orchestration | *CDW*
5520 Research Park | Madison, WI 53711
Phone: 608.298.1061 | Fax: 608.288.3007 | NOC: 608.298.1102 | Toll Free: 
866.202.1807