[Spread-users] 32 bit boundary of sequence numbers

Rodrick Brown rodrick.brown at gmail.com
Mon Feb 2 12:41:50 EST 2009

Alec, this was posted a while back by Jonathan looks like it was fixed
in trunk what version of spread are you using?

[Spread-users] Message sequence counter wrap bug fixed 						Inbox							
Jonathan Stanton to spread-users
show details 10/11/08


I've committed a fix to svn trunk for the problem where sequence numbers
used by the daemons cause a hung daemon when they reach 2^32 (the max
value of the counter). This fix works in my tests, but I would be very
interested in anyone who has had this problem verifing that it also
solves the problem for them. If you have not used the svn trunk before,
you can find instructions at www.spread.org/devel.html

This fix does not change the packet formats of Spread and so is fully
compatible with Spread 4.0 systems. However because it does not increase
the counter size, what it does do is trigger a spurrious membership
change amoung the daemons when the counter gets close to wrapping which
resets it back to 0. This membership will NOT be seen by any of your
client applications, but will cause a short (few second) pause in the
daemon throughput of messages.

Let me know what you think of this.



On Mon, Feb 2, 2009 at 12:34 PM, Alec H. Peterson
<alec.peterson at messagesystems.com> wrote:
> Hi there,
> We use spread on a variety of LAN rings with good results, however we have a
> customer who is experiencing ring lockups.  I've attached the spmonitor
> output from while this issue is happening, but basically it seems like the
> sequence numbers are right around the 32 bit boundary.  We don't have much
> more information to go on at this point, but a cursory look through the
> spread code seems to indicate that it does have a problem when it reaches
> the 32 bit boundary.
> I've attached the spread config file and the spmonitor output while the
> problem was happening.
> Thanks in advance for any help!
> Alec
> --
> Alec H. Peterson - alec.peterson at messagesystems.com
> +1 443 656 3322
> Director of Technical Services
> Message Systems, Inc.
> _______________________________________________
> Spread-users mailing list
> Spread-users at lists.spread.org
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[ Rodrick R. Brown ]
http://www.rodrickbrown.com http://www.linkedin.com/in/rodrickbrown

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