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Old 05-29-2009, 05:03 AM   #1
gontolal
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Red Hat Cluster and fence problem


Hi,

I have two nodes with Red Hat Cluster Suite, when I shutdown one of the two nodes (use the command shutdown -h now) the cluster balancing for the other node correctly.

But when I disconnect the network wire, cluster dont balancing to the other node.

Do I have to use a fence?

I dont configure a fence for the cluster, because I dont have any device for fencing. Is it necessary for the correct balancing?

I have seen that there is a manual option for the fence, working properly and it's automatic?

Best regards
 
Old 05-29-2009, 05:31 AM   #2
druuna
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Hi,

A 'true' cluster has an uneven amount of nodes (3,5,7 etc). If you want to set up a cluster with an even amount of nodes you do need a quorum disk. This is needed because otherwise it is not possible to find out the bad node(s) and a split brain situation can also arise.

True fencing is a hardware solution that can power-off one (or more) nodes if needed to protect the integrity of the data.

The manual fencing is there to provide a test environment. It is _not_ automatic (and it cannot be) and not meant to be used in production environments. Manual fencing will print a message in the log that something is wrong and a human has to take the appropriate action(s).

Here are 2 URL's that could be of interest:

Red Hat Cluster Suite

Red Hat Cluster FAQ

Hope this clears things up a bit.
 
Old 02-02-2010, 02:51 PM   #3
cj_cheema
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Quote:
Originally Posted by druuna View Post
Hi,

A 'true' cluster has an uneven amount of nodes (3,5,7 etc). If you want to set up a cluster with an even amount of nodes you do need a quorum disk. This is needed because otherwise it is not possible to find out the bad node(s) and a split brain situation can also arise.

True fencing is a hardware solution that can power-off one (or more) nodes if needed to protect the integrity of the data.

The manual fencing is there to provide a test environment. It is _not_ automatic (and it cannot be) and not meant to be used in production environments. Manual fencing will print a message in the log that something is wrong and a human has to take the appropriate action(s).

Here are 2 URL's that could be of interest:

Red Hat Cluster Suite

Red Hat Cluster FAQ

Hope this clears things up a bit.

Hi I was going through the posted thread I found it relevant to me.
My query is what method should I use for implement 3 cluster nodes should I use quorum disk for quorum votes because reason is i have 3 nodes cluster configured with HP ILO fence device and dlm as locking machnism sometimes it cluster service got crash when i execute clustat it says cluster is not quorate.

Last edited by cj_cheema; 02-02-2010 at 02:56 PM.
 
  


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