Help - A Sco Unix 5.05 Server Turning into a Pumpkin at Midnight.

[dsweir]

Hello Everybody,

I am seeking some assistance/ideas in regards to a clients server we are working on and that is experiencing some technical issues with.

Since Tuesday this week we have found that at exactly on midnight this particyular server is locking up and freezing. Once the system locks we are still able to switch between the Terminal Sessions on the server, turn the caps on/off on the keyboard however no keyboard input is accepted when we try to login at the login prompt and no background processing appears to be taking place on the server.

As a result of this the only option that we have is to physically power off the server and restart it. Once we have done this the system restarts fine and starts processing again without any problems (excluding some data corrupt we have had to repair due to the power off).

- The problem has occured on past three occasions exactly at 00:00:01.

- There is nothing scheduled within the crontable and to make sure we have disabled this altogether.

- We are unable to see any errors or problem indicators within standard logs.

The site is running 24x7 so any assistance that anyone maybe able to offer would be extremly appreciated.

Thanks

David Weir.

 

[apeasecpc]

Has it happen every midnight since Tuesday or just some midnights?

Have you looked into cron jobs assigned to users other than root?

Another possibility is that something is going wrong with the real time clock, because midnight is when it runs the extra process to increment the day. Does the system freeze if you try to update the date/time using the date function?

 

[MaxKnight]

[tt]
I have had something go wrong with a server with similar symptoms.

However, a clue was left in syslog, it mentioned STREAMS
overflowing, along with misc network errors.

I got the machine to dump some stream stats etc, every 30 seconds, 10 minutes before midnight and spotted something
starting to build up large amouns of errors in the stats.

It turned out to be related to the network card in this
instance, and replacing it fixed it (I also updated it all
to the latest patch levels). I still have no idea what this
had to do with midnight either.

Just something else to consider I guess, sorry I don't
recall any further details that led me to that conclusion.
[/tt]