admin question: howto-unresponsive server under extreme load

[Grant Robinson]

On Dec 11, 2006, at 3:39 PM, Jeff Schroeder wrote:

> Nicholas asked:
>
>> Is there some way to lock a root shell such that it is always
>> responsive so that we could at least kill the webserver and have a
>> chance of the log files being fully written to find the problem?
>
> I don't know for sure, but perhaps you could "nice" the process  
> running
> the shell?
>
> # nice -n -20 bash
>
> A nice-value of -20 is the absolute highest priority (+19 is  
> lowest).  I
> have no idea if this will cause problems with other things on the
> system; perhaps a value of -10 or something would be more appropriate.
> By default, processes are launched with a nice-value of zero.

For good measure you may also want to "nice" your individual SSH  
process, and the root SSH process.  That should make sure that your  
shell and it's network traffic has highest priority in any situation  
short of a DOS attack.

Grant