[ClusterLabs] Antw: Re: Issue with DB2 HADR cluster

[Valentin Vidic]

On Wed, Apr 03, 2019 at 09:13:58AM +0200, Ulrich Windl wrote:
> I'm surprised: Once sbd writes the fence command, it usually takes
> less than 3 seconds until the victim is dead. If you power off a
> server, the PDU still may have one or two seconds "power reserve", so
> the host may not be down immediately. Besides of that power-cycles are
> additional stress for the hardware...
> 
> So maybe you want to explain why and how much faster IPMI and PDU fencing are.

SBD is slow for me too. Since it doesn't have a way to confirm the kill
it needs to wait for various timeouts and these can be quite high. For
example the IBM storage timeouts require this setup:

  Timeout (watchdog) : 130
  Timeout (msgwait)  : 270

On the same cluster IPMI fence executes in a second or two, but requires
network connectivity.

-- 
Valentin