March 6, 2000

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Multinode Clustering:
NetWare Cluster Services Expand On Reliability
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Installing Oracle is only a little more difficult than the previous applications, primarily because the Oracle installation itself is more complex. It requires a dedicated volume, which shouldn't be cluster-enabled. The installation of Oracle is relatively straightforward for a large, capable database, and the installation must be done correctly to one server in the cluster as the next step. Once Oracle is correctly installed, you create an Oracle cluster resource, which, as with the previous two examples, includes templates for unload and load scripts. Once the resource is created, the scripts are edited to include the correct information on the other servers in the cluster and start, failover and failback modes are set.

Netscape Enterprise Server must be installed on all the servers in the cluster to which you might want it to failover. In addition, the administrator password and port number must be the same in every case, the default primary IP address must be used (secondary floating IP addresses can be added later), a shared volume is necessary, but cluster-enabled volumes for data aren't recommended. As with the other applications, once the basic installation is complete, a cluster object is created, thereby creating templates for unload and load scripts. The scripts are edited to designate which Web servers are failed over to which nodes in the cluster.

With Netscape, there's an additional step. The Hardware Virtual Server must be installed on each server in the cluster that will support Netscape, and each Web site on the server must be configured with an IP address that will move from node to node in the event of a failure. Also, there are some lines that must be added to the unload and load scripts for each Web site.

Once all the applications were installed, I tested failover in two ways; first by shutting off one of the servers in the cluster, simulating a hardware failure, then by using ConsoleOne to migrate applications manually from one node to another, as an administrator would do to upgrade a server. In both cases, failover of applications was seamless--even a large print job in the middle of spooling to the server continued on the new server. Once the server was brought back online, applications failed back to the original server.

By using ConsoleOne from the administrative workstation, it was easy to monitor cluster resources as they moved automatically or to move them manually from one node to another.

Even with several large, complex applications installed simultaneously on the same cluster, a configuration many users might not attempt, there were no bobbles as applications moved from one node to another.

NetWare Cluster Services for NetWare 5 supports only NetWare 5, not the newly released NetWare 5.1. NetWare Cluster Services for NetWare 5.1.1 will support NetWare 5.1 and the new Internet services included in NetWare 5.1, and should be available by the end of the first quarter. In addition to support for NetWare 5.1, it will offer a number of other enhancements, including greater DHCP support, which will allow DHCP services to move to any node in a cluster, out-of-box support for up to 32 nodes, and improved management of the cluster.

In all, configuring cluster services and applications on the cluster is relatively simple, especially compared with currently shipping two-node products. The product worked well and the installation was easy, partially because of the templates provided. Installing an application without a template would be a little more complex, since the unload and load scripts would need to be created from scratch. Still, the administrative tools are exemplary.

Since Novell doesn't require specific hardware certification (just that the servers be the minimum configuration for NetWare), and since nodes in the cluster don't even need to be identical and requirements for shared storage are also broad and easy to fulfill, NetWare Cluster Services is much easier to set up than competing products. This product is good enough to bring developers back into the Novell fold, especially once the version that supports NetWare 5.1 is released.

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