IBM SG24-5131-00 User Manual
Special RS/6000 SP Topics
195
9.4 SP Switch as an HACMP Network
One of the fascinating things with an RS/6000 SP is the switch network. It has
developed over time; so, currently there are two types of switches at
customer sites. The “older” HPS or HiPS switch (High Performance Switch),
also known as the TB2 switch, and the “newer” SP Switch, also known as the
TB3 switch.
developed over time; so, currently there are two types of switches at
customer sites. The “older” HPS or HiPS switch (High Performance Switch),
also known as the TB2 switch, and the “newer” SP Switch, also known as the
TB3 switch.
The HPS switch is no longer supported with PSSP Version 3.1, and the same
applies to HACMP/ES Version 4.3.
applies to HACMP/ES Version 4.3.
The two different types of switches differ in their availability design from the
hardware point of view significantly. For example, any fault service action on
the HPS switch caused a total network disruption for a small fraction of time.
For example, running an Estart to get new nodes up on the switch affected
running nodes.
hardware point of view significantly. For example, any fault service action on
the HPS switch caused a total network disruption for a small fraction of time.
For example, running an Estart to get new nodes up on the switch affected
running nodes.
The SP switch however, was designed to do all actions regarding the switch
fabric on the link level, so only the selected node is affected. All the others
continue working without even noticing that something has happened on the
switch network.
fabric on the link level, so only the selected node is affected. All the others
continue working without even noticing that something has happened on the
switch network.
9.4.1 Switch Basics Within HACMP
Although it has already been mentioned in other places, the following is a
short summary of basics you have to remember when you configure a switch
as a network to HACMP.
short summary of basics you have to remember when you configure a switch
as a network to HACMP.
• As the switch network is a point-to-point network, you must configure it to
HACMP as a
private network.
• For IPAT to work on the switch network, you must enable ARP on the
switch network. However, hardware address takeover is not supported
with the switch.
with the switch.
• If you configure IPAT, the service and boot addresses are ifconfig alias
addresses on the
css0
adapter. Since there is currently no support for
more than one switch adapter in a node, this is the way HACMP covers
the normally-needed second adapter for redundancy.
the normally-needed second adapter for redundancy.
• The base address for the switch adapter, i.e. the switch address known to
the SDR, should not be configured into an HACMP network. This would
lead to confusion for the PSSP switch management software.
lead to confusion for the PSSP switch management software.
• The netmask associated with the css0 base IP address is used as the
netmask for all HACMP SP Switch network addresses.