[Linux-cluster] fencing issue - with attach logs&conf

brem belguebli brem.belguebli at gmail.com
Wed Mar 3 23:54:46 UTC 2010


Hi Lon,

The problem could be addressed in a different manner.

Most cluster stacks that I know, in the case of network failure (either
link down or unability to reach the other nodes) but not power, consider
this failure (network) as critical and reboot (hard reboot with no sync)
the failing node (reboot generally achieved by a watchdog mechanism).

The other nodes can take over the services, after a configurable timer.

This ensures storage won't be mounted on 2 different nodes and thus
prevent the corruption possibility (a fsck is run on the taking over
node).   

Brem 


On Wed, 2010-03-03 at 17:00 -0500, Lon Hohberger wrote:
> On Wed, 2010-03-03 at 13:10 +0200, שלום קלמר wrote:
> > Hi.
> >  
> > I got 2 power supplies. But if someone by mistake pull the power
> > cables , is that mean
> >  
> > That the services will not failover ??
> 
> The problem is:
> 
> no power = no ping + no DRAC access
> no network = no ping, no DRAC access
> 
> If there's no power, then it is safe to fail over.
> 
> If there is no network (and power is OK), then it is not safe to fail
> over.  Failover in this case is very likely to produce data corruption!
> 
> Because we can not tell which case happened, we do not fail over.
> 
> -- Lon
> 
> 
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