IBM AIX HACMP SG24-5131-00, Hardware User Manual

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© Copyright IBM Corp. 1999
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Chapter 10. HACMP Classic vs. HACMP/ES vs. HANFS
So, why would you prefer to install one version of HACMP instead of
another? This chapter summarizes the differences between them, to give you
an idea in which situation one or the other best matches your needs. The
certification test itself does not refer to these different HACMP flavors, but it is
useful to know the differences anyway.
The following paragraphs are based on the assumption that you are using
Version 4.3. For an overview of previous Versions and their corresponding
AIX levels, as well as the supported hardware to run on, see Table 3 on page
8.
10.1 HACMP for AIX Classic
High Availability Cluster Multi-Processing for AIX (HACMP for AIX) Version
4.3 comes in two flavors. One of them directly derives from previous versions,
and therefore is called Classic, and the other, which utilizes another
technology for heartbeating, is called HACMP Extended Scalability
(HACMP/ES) see below for details.
Basically, these two versions differ only in the way the cluster manager keeps
track of the status of nodes, adapters and networks. In the Classic Version,
this is done through the use of Network Interface Modules.
Network Interface Modules (NIMs) monitor the nodes and network
interfaces associated with a cluster. Each
network module monitors one cluster network
using one kind of communication protocol (for
example, Ethernet or FDDI). Each network
module is responsible for maintaining
keepalive traffic with neighboring nodes as
directed by the Cluster Controller, for
providing a link to other nodes on the network
it monitors, and for initiating adapter swaps on
certain networks.
10.2 HACMP for AIX / Enhanced Scalability
HACMP/ES no longer used NIMs, but utilizes a technolgy that was originally
developed on the RS/6000 SPs. Since PSSP Version 2.2. RS/6000 SP
Systems come with the Phoenix technology for managing availability of the
nodes. This technology was already designed as a basic instrument for