[Clusterusers] hex issues

[Ryan Moore]

'Max instances' and 'connections per second' are there to keep bad code 
from spawning enough connections to create a process overflow and take 
down the server. (How much do you guys trust your students? one bad loop 
and it's all over). I'll raise up the numbers  a lot more and we'll see 
what happens. Also, I'll restart the rsh daemon as well as the xinetd 
daemon. Give me about ten minutes.

- Ryan

Lee Spector wrote:

> --- old stuff first ---
>
> This sounds right, and the test does what you predicted -- it got from 
> n23 down to n04.
>
> So I guess there's a TCP/IP limit that should be jacked up.
>
> FYI the communication for my systems is all master<->node, with none 
> directly node<->node. But maybe for others we should ensure that heavy 
> node<->node traffic is also permitted?
>
> ---- AH, just got your new mail ----
>
> The fix sounds good, but I've just started a run since getting your 
> mail and it's still choking... Does something else need to be 
> restarted/rebooted?
>
> Also, is there a reason not to jack things up higher (you did 
> "increased the max instances parameter up to 80 from 60 and I 
> increased the 'connections per second' parameter up to 30 from 25."). 
> If I'm hitting the limits now then mightn't we hit it a lot more when 
> there's more usage in the future? Or other kinds of applications? Is 
> there any downside to setting max instances to 600 or whatever (and 
> similarly for connections per second)? I wonder if the limits aren't 
> set as they are because that makes more sense for server farm 
> applications and the like, where the network requests come from the 
> outside? But when we do a lot of networking it's because our 
> applications demand it, and we want the messages to go through 
> regardless of the delays from bottlenecks... Just a thought.
>
> Thanks,
>
>  -Lee
>