The IBM TotalStorage NAS Gateway 500 Integration Guide

Chapter 10. Remote Mirroring configuration 251

򐂰 In which order should the setup be performed? It is possible to install and

configure two NAS 500 Gateways on the different locations. This makes it

hard to find any performance problems which are not GeoNetwork related.

Also, the initial configuration from one site can only be performed if there is a

communication path existing to the remote site. The other possibility is to

configure both systems first on one site to make all run and then ship one

node to the remote site.

The more nodes are involved, the more complex the environment will become.

Good planning is really necessary, since otherwise you could get in real trouble

during or after the configuration. We recommend that you use the planning

sheets that are provided with the IBM TotalStorage NAS Gateway 500 Planning

Guide, GA27-4335-01, and clarify all open points before you start your

installation.

10.2.1 Supported configurations

The NAS Gateway 500 supports the following two configurations.

Serial lines

The NAS Gateway 500 has three serial ports. Port one is for connecting a

terminal or laptop with a terminal emulation program, port two is for attaching a

modem which can do a call home to IBM if a problem exists and port three is

either for a UPS connection or if you have a local cluster or 2 nodes at the same

site for the cluster heartbeat. With the NAS Gateway 500 it is not supported to

use a serial network between the sites.

Ethernet

GeoNetworks have to be independent of the file serving networks, a minimum

requirement includes separate Ethernet ports. These should be attached to

independent Ethernet switches that support link aggregation. Link aggregation

allows the GeoNetwork connection to survive a failure of a network adapter in the

NAS Gateway 500.

10.3 Two-node cluster configuration

In this section we show you how to configure a simple, active/standby, two-node

HACMP/XD cluster with NAS Gateway 500.

Note: All IP addresses, names, and adapter slot numbers specified in this

section are for our sample configuration. You may have different slot numbers

of adapters, names, and IP addresses for your configuration.

252 The IBM TotalStorage NAS Gateway 500 Integration Guide

10.3.1 Our cluster topology

We have two sites: Beijing (the local site), and Frankfurt (the remote site).

There are two nodes: The node in site Frankfurt is node Frankfurt_A, and the

node in site Beijing is node Beijing_A.

As shown in Figure 10-4 on page 254, we connect the Gigabit Ethernet ports to

the client network and the GeoNetworks. The cluster subnet mask is

255.255.255.0.

The boot IP addresses assigned to boot adapters are listed in Table 10-1; they

are connected to the file serving network.

Table 10-1 Boot IP address assignment of our cluster

We use one file serving IP address to serve clients:

򐂰 192.168.40.1 for NFS file sharing

We have two GeoNetworks for remote mirroring and cluster heartbeat. The IP

addresses of the member Ethernet ports are listed in Table 10-2.

Table 10-2 IP addresses in GeoNetworks

Ethernet port Boot IP address

Beijing_A, TX Ethernet adapter slot 2, port 1 192.168.30.1

Beijing_A, TX Ethernet adapter slot 6, port 2 192.168.60.1

Frankfurt_A, TX Ethernet adapter slot 2, port 1 192.168.30.2

Frankfurt_A, TX Ethernet adapter slot 6, port 2 192.168.60.2

Ethernet port IP address/network

Beijing_A, SX Ethernet adapter port 1 10.100.100.1/GeoNetwork 2

Beijing_A, TX Ethernet adapter slot 6, port 1 192.168.50.1/GeoNetwork 1

Frankfurt_A, SX Ethernet adapter port 1 10.100.100.2/GeoNetwork 2

Frankfurt_A, TX Ethernet adapter slot 6, port 1 192.168.50.2/GeoNetwork 1

Chapter 10. Remote Mirroring configuration 253

10.3.2 Remote mirroring device

We have one NAS volume to be remotely mirrored: volnfs. Each node has logical

drives defined on the FAStT storage server which is located at the same site.

10.3.3 Our resources

We use one inter-site shared filesystem.

The resource groups in our cluster are as follows:

򐂰 Volume groups: the volume groups for the NAS volume volnfs on each node

򐂰 File systems to be NFS exported: /Vols/volnfs

򐂰 File serving IP addresses: 192.168.40.1

򐂰 Preferred owner: beijing_A

򐂰 Backup node: frankfurt_A

Note: Even when configuring a cross-geographical cluster, the way that NAS

Gateway 500 sends and receives heartbeat messages over TCP/IP networks

is not changed, compared with the intra-site cluster configuration. The cluster

software still requires adapters within a network (whether a file serving

network or a GeoNetwork) to be in a single VLAN. A cross-geographical VLAN

can be built by switches and bridges.

There is another method that has been used before in HACMP/XD solutions

with pSeries servers, which uses routers to connect the cross-geographical

networks and “cheat” the cluster software via IP subnetting techniques.

However, this method is not tested in our lab environment.