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PowerHA 6 vs PowerHA System Mirror


What is the main difference between power HA 6 and powerHA System Mirror?
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the main difference is that PowerHA 7 is no longer based on the "Reliable Scalable Cluster Technology" (RSCT) product, which provided topology services for HACMP and PowerHA 6.

Instead, PowerHA 7 uses AIX's new feaurure "Cluster Aware AIX" (CAA) and the related services.
This is considered an increase in reliability, because the topology services now run kernel-based and are thus much less affected by user-space workload.

PowerHA 7 now requires the use of a shared repository disk (a CAA feature) containing vital information about cluster topology and resources.
Communication paths to this disk are used as fallback heartbeat lines, thus making SAN-based heartbeating obsolete.

The still mandatory TCP/IP based heartbeat connection now works via multicast over all network interfaces that are available for cluster communication. All of these interfaces are discovered by default and used for health management and other cluster communication.

There is a new feature called the "Tie Breaker Disk" which helps in managing split-brain situations, by deciding which node will survive a such a situation - the one that succeeds in placing a SCSI-3 persistent reserve on the tie breaker disk wins.

To implement the above several changes in the ODM representation of the cluster configuration have been made.

There are various new features in version 7, like:

- Stretched and linked clusters
- New split/merge handling
- HyperSwap (storage-based synchronous replication)
-  IPv6 support
- New Smart Assists (DB2/DHCP/DNS/Domino/HTTP/SAP/Oracle/TSM/Websphere  ...)
- Support for IBM Systems Director

To learn more about new features and how to set up PowerHA System Mirror version 7 please read the Redbooks:


mokkanAuthor Commented:
Thank  you
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