Re: Director Failover

Yes, I have sync master and sync backup in the
directors.

So if I can see the connection using ipvsadm -lc in
the backup director, the connection should not be
disconnected during director failover (at least for
telnet), right ?


Thanks
Chee Chye

 --- Sébastien Bonnet <[email protected]>
wrote: > > Does a connection *always* survive a
director
> failover ?
> 
> I'm no sync guru, your question should get better
> answered on the LVS
> mailing list :)
> BTW, here is what I understand (simplified) :
> Once a connection is established, the master sync
> daemon (on the active
> director) sends data to the backup sync daemon (on
> the backup director).
> The backup director is then aware of an established
> connection. If the
> primary director fails, the backup will take over
> and still forward
> packets from an established connection to the right
> reral server.
> 
> This works fine on long lasting connections
> (interactive sessions like
> FTP, telnet, SSH and so on) but doesn't on short
> connections (http
> without keepalive for example).
> 
> > So it seems to me it's not *always* that a
> connection can survive
> > a director failover. Am I right ?
> 
> It won't *always* survive for a very simple reason :
> if the primary
> director fails before its master sync daemon can
> send data about the new
> connections to the backup sync daemon, the backup
> won't forward incoming
> packets (related to a formerly established
> connection) because it
> doesn't know the connection.
> 
> > P.S. I had the syncdaemon up in both primary and
> > backup director as shown below:
> > root      7933     1  0 15:00 ?        00:00:00
> [ipvs syncbackup]
> 
> Just to make sure, do you have a sync master and a
> sync backup ?
> 
> -- 
> Sébastien Bonnet
>   Centre de contacts - Experian France
> 
> 
> 
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>
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