Blocked process

[CmdLnKid]

On Thu, 20 Aug 2009 08:42 -0000, doconnor wrote:

> On Thu, 20 Aug 2009, Kostik Belousov wrote:
>>> Things like ls on the console might take several seconds to respond
>>> when the box didn't seem to be very busy (but wasn't idle, maybe
>>> serving a little NFS). It wasn't the shell getting swapped out or
>>> anything else obvious. This was on SMP, not using X. The problem
>>> went away with 6.4R (had to stay with 6.x for unrelated reasons).
>>
>> 6.1 was released with a bug in NFS server, causing serious slowdown
>> when non-MPSAFE fs was exported.
>
> Hmmm.. this is 6.2 (and a half) so I guess that's not my problem.
>
> Next! ;)
>

I had a problem like this once when the NFS mount stopped responding and 
any command that was issued seemed to hang. This all was happening while 
not paying attention to the NFS mount and that mount being various 
directories under /var and including /var/mail. A little deeper I 
eventually came across and what made me feel pretty stupid is that the 
"$SHELL" whether it be csh, ksh, bash or sh checks for mail on command 
completion or invocation and being so that the NFS mount stopped 
responding the process would hang until the mount came back or the 
machine was rebooted. I continued for a while using /var/mail over NFS 
while setting or unset mail variables for the shell. You may also 
want to check into whether something is trying to acquire a lock on a 
file over that NFS mount which could accrue some extra time making it 
seem like a process is hung.

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  - (2^(N-1))