[ClusterLabs] Corosync main process was not scheduled for 2889.8477 ms (threshold is 800.0000 ms), though it runs with realtime priority and there was not much load on the node

[Jan Friesse]

Jeevan,

Jeevan Patnaik napsal(a):
> Hi,
> 
> Also, both are physical machines.
> 
> On Fri, Aug 30, 2019 at 7:23 PM Jeevan Patnaik <g1patnaik at gmail.com> wrote:
> 
>> Hi,
>>
>> We see the following messages almost everyday in our 2 node cluster and
>> resources gets migrated when it happens:
>>
>> [16187] node1 corosyncwarning [MAIN  ] Corosync main process was not scheduled for 2889.8477 ms (threshold is 800.0000 ms). Consider token timeout increase.
>> [16187] node1 corosyncnotice  [TOTEM ] c.
>> [16187] node1 corosyncnotice  [TOTEM ] A new membership (192.168.0.1:1268) was formed. Members joined: 2 left: 2
>> [16187] node1 corosyncnotice  [TOTEM ] Failed to receive the leave message. failed: 2
>>
>>
>> After setting the token timeout to 6000ms, at least the "Failed to
>> receive the leave message" doesn't appear anymore. But we see corosync
>> timeout errors:
>> [16395] node1 corosyncwarning [MAIN  ] Corosync main process was not
>> scheduled for 6660.9043 ms (threshold is 4800.0000 ms). Consider token
>> timeout increase.
>>
>> 1. Why is the set timeout not in effect? It's 4800ms instead of 6000ms.

It is in effect. Threshold for pause detector is set as 0.8 * token timeout.

>> 2. How to fix this? We have not much load on the nodes, the corosync is
>> already running with RT priority.

There must be something wrong. If you increase token timeout even higher 
(let's say 12sec) is it still appearing or not? If so, isn't the machine 
swapping (for example) or waiting for IO? If you try to run it without 
RT priority, does it help?

Regards,
   Honza


>>
>> The following is the details of OS and packages:
>>
>> Kernel: 3.10.0-957.el7.x86_64
>> OS: Oracle Linux Server 7.6
>>
>> corosync-2.4.3-4.el7.x86_64
>> corosynclib-2.4.3-4.el7.x86_64
>>
>> Thanks in advance.
>>
>> --
>> Regards,
>> Jeevan.
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>>
> 
> 
> 
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