[ClusterLabs] Antw: [EXT] Re: maximum token value (knet)

[Ulrich Windl]

>>> Jan Friesse <jfriesse at redhat.com> schrieb am 11.03.2021 um 18:12 in Nachricht
<e6bf446a-186e-053c-8bdc-921c6f7e9feb at redhat.com>:
> Strahil,
>> Hello all,
>> I'm building a test cluster on RHEL8.2 and I have noticed that the cluster 
> fails to assemble ( nodes stay inquorate as if the network is not working) if 
> I set the token at 30000 or more (30s+).


Hi!

I know you will be bored when I say this, but anyway:
In old HP Service Guard the node connectivity was checked with ping/pong too, and you could specify the interval and the number lost responses that declare a node unreachable. The good thing (as opposed to the TOTEM protocol I know) was that single missed responses were logged, so you did not just have an OK/BAD status, but also an indicator how far you are away from BAD status.

So you have a token timeout of 30s, and we had 3 lost responses at an interval of 7 seconds (at that time the 100Mb NIC needed about 5 seconds to renegotiate after a link failure (like unplug/replug). Recent hard- and software is somewhat faster AFAIK.

Regards,
Ulrich

> 
> Knet waits for enough pong replies for other nodes before it marks them 
> as alive and starts sending/receiving packets from them. By default it 
> needs to receive 2 pongs and ping is sent 4 times in token timeout so it 
> means 15 sec until node is considered up for 30 sec token timeout.
> 
>> What is the maximum token value with knet ?On SLES12 (I think it was  
> corosync 1) , I used to set the token/consensus with far greater values on 
> some of our clusters.
> 
> I'm really not aware about any arbitrary limits.
> 
>> Best Regards,Strahil Nikolov
>> 
> 
> Regards,
>    Honza
> 
>> 
>> 
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