[ClusterLabs] Antw: Re: Two node cluster goes into split brain scenario during CPU intensive tasks

[Jan Pokorný]

On 01/07/19 13:26 +0200, Ulrich Windl wrote:
>>>> Jan Pokorný <jpokorny at redhat.com> schrieb am 27.06.2019 um 12:02
>>>> in Nachricht <20190627100209.GF31192 at redhat.com>:
>> On 25/06/19 12:20 ‑0500, Ken Gaillot wrote:
>>> On Tue, 2019‑06‑25 at 11:06 +0000, Somanath Jeeva wrote:
>>> Addressing the root cause, I'd first make sure corosync is running at
>>> real‑time priority (I forget the ps option, hopefully someone else can
>>> chime in).
>> 
>> In a standard Linux environment, I find this ultimately convenient:
>> 
>>   # chrt ‑p $(pidof corosync)
>>   pid 6789's current scheduling policy: SCHED_RR
>>   pid 6789's current scheduling priority: 99
> 
> To me this is like pushing a car that already has a running engine! If
> corosync does crazy things, this will make things worse (i.e. enhance
> crazyness).

Note that said invocation is read-only fetch of the process
characteristic.  So not sure about your parable, it shall
rather be compared to not paying full attention to driving
itself for a bit when checking the speedometer (the check
alone won't presumably run with such an ultimate scheduling
priority, so the interferences shall be fairly minimal, just
as with `ps` or whatever programmatic fetch of such data).

>> (requires util‑linux, procps‑ng)

-- 
Jan (Poki)
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