rsh slow shutdown

rick bradshaw bradshaw at mcs.anl.gov
Sat Mar 15 13:47:17 EST 2003


Egan,
        yes I am aware of using ssh and mpd instead but what I would
like is to findout why it says that it is not configured properly. I
know that the amount of ports limit it but that still doesn't explain
why I can't get it even close to the max?

Rick

"Egan Ford" <egan at sense.net> writes:

> rsh uses privileged ports (512-1023).  So, there is a limited number of
> them.  Other processes use the privileged ports reducing the total number
> available.  rsh may also use 2 ports (one for stderr and one for stdout so
> I've been told, but I have not seen it), and you'll also need one/processor,
> not just one/node.
>
> I recommend using ssh with non-privileged ports, then you can startup any
> size job < 65536-1024 processors.
>
> Other solutions exist using MPD and scalable rsh implementations (e.g.
> pdsh).  
>
> Turn around and ask J.P., he knows about this.
>
>> -----Original Message-----
>> From: beowulf-admin at beowulf.org 
>> [mailto:beowulf-admin at beowulf.org] On Behalf Of rick bradshaw
>> Sent: Thursday, March 13, 2003 9:04 AM
>> To: beowulf at beowulf.org
>> Subject: rsh slow shutdown
>> 
>> 
>> I am wondering if anyone knows the solution to the following
>> problem. I know first of all that rsh is not scalable but it should be
>> able to hit 255 or so processes, but recently I received the following
>> message when running 208 processes
>> 
>> Timeout in waiting for processes to exit, 16 left.  This may 
>> be due to a defective
>> rsh program (Some versions of Kerberos rsh have been observed 
>> to have this
>> problem).
>> This is not a problem with P4 or MPICH but a problem with the 
>> operating
>> environment.  For many applications, this problem will only slow down
>> process termination.
>> 
>> I will also include the fact that I am running redhat 7.3 with rsh
>> from the redhat rsh-0.17-5 rpm.
>> 
>> Thanks in advance for the help.
>> 
>> Rick Bradshaw
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