'ls' hangs FC6
Mark Haney
mhaney at ercbroadband.org
Thu Apr 10 18:37:23 UTC 2008
Todd Denniston wrote:
> Mark Haney wrote, On 04/10/2008 02:06 PM:
>> Rick Stevens wrote:
>>> Paul Johnson wrote:
>>>> On Wed, Apr 9, 2008 at 1:26 PM, Mark Haney <mhaney at ercbroadband.org>
>>>> wrote:
>>>>> Does anyone have any ideas on why 'ls' would suddenly stop working?
>>>>> I've got
>>>>> a FC6 box that acts as a SAN host and for the last week or so I
>>>>> can't ls
>>>>> anything. It sits and does nothing. Everything else on the box
>>>>> works just
>>>>> fine except for that.
>>>>>
>>>>> I've got no idea how to even go about debugging this.
>>>>>
>>>>
>>>> I have seen this on systems that are using LDAP for authentication.
>>>> They don't just authenticate at start time, but they look up user
>>>> information every time. Every single time any command is run, the
>>>> system goes off to check user identity on a server. When there is
>>>> network slowdown or server slowdown, then ls is slow. For us, the
>>>> short term fix was to install the nscd to cache the information so the
>>>> system does not constantly look on the server. The long term fix was
>>>> to stop authenticating users with LDAP.
>>>
>>> Or run "ls -ln" so you don't do user/group lookups and simply display
>>> the numbers.
>>>
>> It must be something with the user/group lookups then because an ls-ln
>> works just fine. I just can't figure out /why/ it's a problem now.
>
> does the ls which hangs, output SOME of the info before it hangs?
> perhaps something like the following could be useful...
>
> for i in *
> do
> OPTIONS_THAT_HANG_LS="--color=tty"
> /bin/ls $OPTIONS_THAT_HANG_LS $i && \
> echo "$i" >> /tmp/files_that_did_not_hang_ls.txt &
> done
>
> of course you'll have a bunch of ls's hanging when this is done.
> `killall -9 ls` them?
>
> /bin/ls > /tmp/wholedir.txt
> diff -u /tmp/files_that_did_not_hang_ls.txt \
> /tmp/wholedir.txt | \
> grep -e "+" >/tmp/trouble
>
> then for the files in /tmp/trouble (after looking to see if someone on
> this list does not pull a flamethrower on Todd for the suggestion)
> for i in $TROUBLEMAKERS
> do
> #just ignore the problem
> #chown root:root $i
> #If that don't fix it, I am at a loss,
> #or you are loosing hardware.
> #
> #try to figure out if it is a consistent user
> # or group causing the problem.
> #ls -ln $i
> done
>
>
>
Strangely the system hangs before displaying ANY files. If it did a
few, it might be something I could nail down myself.
Now, I'm getting more and more sure that it's a user/group resolution
problem since the ls -ln option works in every case where both ls and ls
-l hang.
--
Libenter homines id quod volunt credunt -- Caius Julius Caesar
Mark Haney
Sr. Systems Administrator
ERC Broadband
(828) 350-2415
Call (866) ERC-7110 for after hours support
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