[Info-vax] Production VMS cluster hanging with lots of LEFO

[VAXman- at SendSpamHere.ORG]

In article <dd549999-4436-4e6a-98fa-dbeb612d7cea at w35g2000yqm.googlegroups.com>, filip.deblock at proximus.net writes:
>{...snip...}
>
>A lot of unknowns are still left.
>
>Q : what caused the image activator to go into LEFO (actual to remain
>in
>LEFO). At some point during image activation (last phase ?) it starts
>waiting for an eventflag. What could be setting that event flag ? I am
>suspecting it never came ...

The "image activator" was in LEFO!  I didn't know there was a separate
process known as the "image activator".

What caused processes to go into LEFO is the VMS process scheduling's
algorithms and the SWAPPER.  These processes were selected as candid-
ates for outswapping because the system determined it needed to free
up memory for something else on the system.



>Q: crashing (and rebooting) the quorum node solved things immediately.
>Could
>this be caused by a lock held by the quorum node ? if so, is this a
>lock that is
>related to cluster transitions ?

If the quorum node isn't doing anything, it's highly unlikely that it
held any lock(s) that caused your issue.


>Q : would we have had the same effect by crashing/rebooting anyone of
>the
>other nodes ?

Don't know.  


>And finally :
>
>Can some form of (minor ?) network outage trigger events like this?

Perhaps.


>Any takers ?

Next time this should happen, force a crash DUMP to be written such 
that there is post mortem information to analyze the cause of your
problem(s).

What you did by stopping the LEFO processes was akin to going into 
battle and shooting the already dead.  I would have looked for one
or more processes on the system consuming memory.  

Did you SHOW MEMORY[/PHYSICAL]?   If so, what did you see on the
FREE and MODIFIED lists?

I'd guess that the FREE list was low and the system went into action
to free up pages by outswapping dormant processes.

-- 
VAXman- A Bored Certified VMS Kernel Mode Hacker    VAXman(at)TMESIS(dot)ORG

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