Re: ZMailer scheduler stuffing up severely...

[Michael Loftis <mloftis@wgops.com>]

Matti Aarnio wrote:

> On Mon, Oct 08, 2001 at 02:06:15PM -0700, Michael Loftis wrote:
> >
> > OK my system is doing deliveries but not at what it is capable of.
> > The routers seem to be picking up from the router dir plenty fast
> > enough, but scheduler fallls *massively* behind in processing queue.
> > If I stop zmailer, then restart it (witht he synchronous start option)
> > it reads in the queue and *FLIES* just fine.
> > But during normal operations the damned thing just stuffs up.
> > Whats the deal?
>
>    Which version of ZMailer ?  At what kind of system ?
>    ( UNIX version, and hardware, amount of RAM. )

Zmailer 2.99.55
FreeBSD 4.3-p20
2xPii450 512MB RAM


>    I think I have seen this jamming phenomena once or twice awhile ago.
>
>    Ah! Recollection hits!  I guess the bug is due to crash of "timeserver".
>    But why it crashes/stops ?  And why won't it recover ?  Can you tell
>    me more about your system ? (Hardware, amount of memory, UNIX version ...)

timeserver?  Well the scheduler keeps going, but it doesnt' seem to be picking up
new messages that are dropped off by router, or if it is it's going about it
majorly slowly.  IT's alwo very slow at getting them out.  We've routinely seen
the thing break 1Mbit a second at a run for 10-15 minutes or more, but seems that
things have stuffed up at times though.

>    ZMailer scheduler contains a shared-segment subprocess which ticks
>    2-3 times a second, and updates gettimeofday() data in that segment.
>    The main scheduler reads this data.    (The thing could also be done
>    with couple other ways which use interval timer to kick the time
>    reading, and not using subprocess.    When I did the current system,
>    I had previously done one server where a statistics summarizer / clock
>    ticker is shared in between few hundred parallel running customer
>    instantiated server processes.)

Ahhhh!!!!  OK!  I've got it then!!  We're running a fairly high process server
and probably you're eating us out of shared memory segments!

> <THWACK!>
>
>    Death of timeserver ?

Sounds like it, I'll make some adjustments to shared memory and PMAPs and see
what we can get.  PRobably need to beef up NMBCLUSTERs as well.

*todders off to do kernel tuning*  IF anyone has any recommendations I'd love to
hear them.

>

>
>
> --
> /Matti Aarnio   <mea@nic.funet.fi>

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