NIS exhausts system resources

[Dan Pelleg]

Terry Lambert writes:
 > Dan Pelleg wrote:
 > > When does this happen, you ask? I triggered it this morning by booting the
 > > machine when the NIS server was down. I had also seen it in the past when
 > > configuring NIS, and it happened as soon as I set the domainname.  Any
 > > ideas? I can provide packet captures on request, however note the failure
 > > where the server is down.
 > 
 > Historical behaviour when the NIS server is down has been for the
 > client machines to hang until the NIS server is back up.
 > 
 > FreeBSD doesn't serialize NIS requests trough a single local daemon,
 > so it doesn't hang "like it's supposed to".
 > 
 > It's probably that you could reorder the source code to ensure that
 > no file opens (other than sockets) are held across an NIS request;
 > this would certainly reduce pressure on the number of open files.
 > 
 > Note that since you are SSH'ing in, and have other processes running,
 > most likely, you just need to increase "MAXUSERS" to increase the
 > maximum number of open files, and let them hang simultaneously,
 > instead of running out of descriptors.
 > 

I'm not sure I understand this. First, if the server is down when the
client boots, this will stop the client's boot sequence (or at least slow
it significantly down). sshd isn't given a chance to start. The only sign
of life from the machine at this point is ICMP replies and the sound of the
grinding disk (probably syslogd).

Next, this is a wimpy machine. 233Mhz processor and 64MB of RAM. I don't
know if that matters or not, but I'm not confident of my ability to tweak
the memory usage on it.


 > In general, NIS servers are not supposed to go down, ever.
 > 
 > -- Terry