SuSE Linux Enterprise Server OpenSSH 5.1p1 nagle issue?

[Jeremy Guthrie]

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