Personal guesses, YMMV, YKWYPFI (you know what you paid for it), etc:

If you don’t need NFS, leave it off.  When I saw it in  there I thought – oh, my.  For NFS clients, I know you can freeze a system when the server goes unresponsive.  Or I think I know that J

Of all those things, are there any you are NOT using?

Besides the ping test mentioned earlier, I suppose you could start dividing and conquering (turn back on half the items below, run the test.  If passes, run the other half to verify that the mix of the other half will fail, THEN split the failing half in half and repeat).

I can’t recall if I’ve ever seen a hung printer hang cups enough to hang the entire system.  It will hang printing, of course, but…

In any case, yes it sounds like some sort of hw/sw interaction or maybe just sw.

Good luck, Mr Phelps!  ;-)

Rusty

From: plug-discuss-bounces@lists.plug.phoenix.az.us [mailto:plug-discuss-bounces@lists.plug.phoenix.az.us] On Behalf Of Mark Phillips
Sent: Wednesday, June 27, 2012 6:51 AM
To: Main PLUG discussion list
Subject: Re: Strange Server Behavior

Some more pieces to the puzzle...

I ran the same ping test last night (laptop to server), but stopped the following services on the server:
apache2
exim4
mediatomb
mysql
nfs-kernel-server
nfs-common
openvpnas
cups
ntp
rpcbind

And there were no packets lost!

2802 packets transmitted, 2802 received, 0% packet loss, time 28010243ms
rtt min/avg/max/mdev = 0.063/0.157/0.319/0.033 ms

This is all that was running:
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root         1  0.0  0.0   2036   736 ?        Ss   Jun25   0:01 init [2] 
root         2  0.0  0.0      0     0 ?        S    Jun25   0:00 [kthreadd]
root         3  0.0  0.0      0     0 ?        S    Jun25   0:00 [migration/0]
root         4  0.0  0.0      0     0 ?        S    Jun25   0:00 [ksoftirqd/0]
root         5  0.0  0.0      0     0 ?        S    Jun25   0:00 [watchdog/0]
root         6  0.0  0.0      0     0 ?        S    Jun25   0:00 [events/0]
root         7  0.0  0.0      0     0 ?        S    Jun25   0:00 [cpuset]
root         8  0.0  0.0      0     0 ?        S    Jun25   0:00 [khelper]
root         9  0.0  0.0      0     0 ?        S    Jun25   0:00 [netns]
root        10  0.0  0.0      0     0 ?        S    Jun25   0:00 [async/mgr]
root        11  0.0  0.0      0     0 ?        S    Jun25   0:00 [pm]
root        12  0.0  0.0      0     0 ?        S    Jun25   0:00 [sync_supers]
root        13  0.0  0.0      0     0 ?        S    Jun25   0:00 [bdi-default]
root        14  0.0  0.0      0     0 ?        S    Jun25   0:00 [kintegrityd/0]
root        15  0.0  0.0      0     0 ?        S    Jun25   0:00 [kblockd/0]
root        16  0.0  0.0      0     0 ?        S    Jun25   0:00 [kacpid]
root        17  0.0  0.0      0     0 ?        S    Jun25   0:00 [kacpi_notify]
root        18  0.0  0.0      0     0 ?        S    Jun25   0:00 [kacpi_hotplug]
root        19  0.0  0.0      0     0 ?        S    Jun25   0:00 [kseriod]
root        21  0.0  0.0      0     0 ?        S    Jun25   0:00 [kondemand/0]
root        22  0.0  0.0      0     0 ?        S    Jun25   0:00 [khungtaskd]
root        23  0.0  0.0      0     0 ?        S    Jun25   0:00 [kswapd0]
root        24  0.0  0.0      0     0 ?        SN   Jun25   0:00 [ksmd]
root        25  0.0  0.0      0     0 ?        S    Jun25   0:00 [aio/0]
root        26  0.0  0.0      0     0 ?        S    Jun25   0:00 [crypto/0]
root       154  0.0  0.0      0     0 ?        S    Jun25   0:00 [ksuspend_usbd]
root       155  0.0  0.0      0     0 ?        S    Jun25   0:00 [khubd]
root       157  0.0  0.0      0     0 ?        S    Jun25   0:00 [ata/0]

So, perhaps I don't have a hardware problem, but a software problem?

Mark