Friday, February 15, 2008

HACMP topology & usefull commands

Hacmp can be configured in 3 ways.

1. Rotating
2. Cascading
3. Mutual Failover

The cascading and rotating resource groups are the “classic”, pre-HA 5.1 types. The new “custom” type of resource group has been introduced in HA 5.1 onwards.


Cascading resource group:
Upon node failure, a cascading resource group falls over to the available node with the next priority in the node priority list.
Upon node reintegration into the cluster, a cascading resource group falls back to its home node by default.

Cascading without fallback
Thisoption, this means whenever a primary node fails, the package will failover to the next available node in the list and when the primary node comes online then the package will not fallback automatically. We need to move package to its home node at a convenient time.

Rotating resource group:
This is almost similar to Cascading without fallback, whenever package failover to the standby nodes it will never fallback to the primary node automatically, we need to move it manually at our convenience.

Mutual takeover:
Mutual takeover option, which means both the nodes in this type are active-active mode. Whenever fail over happens the package on the failed node will move to the other active node and will run with already existing package. Once the failed node comes online we can move the package manually to that node.

Useful HACMP commands

clstat - show cluster state and substate; needs clinfo.
cldump - SNMP-based tool to show cluster state
cldisp - similar to cldump, perl script to show cluster state.
cltopinfo - list the local view of the cluster topology.
clshowsrv -a - list the local view of the cluster subsystems.
clfindres (-s) - locate the resource groups and display status.
clRGinfo -v - locate the resource groups and display status.
clcycle - rotate some of the log files.
cl_ping - a cluster ping program with more arguments.
clrsh - cluster rsh program that take cluster node names as argument.
clgetactivenodes - which nodes are active?
get_local_nodename - what is the name of the local node?
clconfig - check the HACMP ODM.
clRGmove - online/offline or move resource groups.
cldare - sync/fix the cluster.
cllsgrp - list the resource groups.
clsnapshotinfo - create a large snapshot of the hacmp configuration.
cllscf - list the network configuration of an hacmp cluster.
clshowres - show the resource group configuration.
cllsif - show network interface information.
cllsres - show short resource group information.
lssrc -ls clstrmgrES - list the cluster manager state.
lssrc -ls topsvcs - show heartbeat information.
cllsnode - list a node centric overview of the hacmp configuration.

6 comments:

Mark said...

Useful blog thanks!

shinji said...

Very usefull to me Thanks Santosh Gupta

Shinjith - Aix Admin

Ramachandran said...

Very useful commands,Thanks a lot dear.

Ramachandran (Aix).

Amer said...

Thanks Buddy, U created a very good blog for AIX Admins. Thanks again.

Sreekanth said...

Excellent Santosh...your blog is much helpful to us....:)

Umang Garg said...

Hi,

Very useful blog.. thanks santosh for creating this and sharing your knowledge.

I have one question, so i thought to discuss over there.

I am working in the environment where we have active passive two node cluster and when one node fails, the resource move to next node. But it will not fallback when the primary node comes up. How to solve this.. Please suggest and give example with smitty.

Thanks.