BOSTON (05/23/2000) - "Mission critical" today translates in its basic form to server uptime. But it's hard to know what the best option is for ensuring uptime in your environment. Do you put all your eggs in one basket and go with a new megaserver? Or do you distribute applications across multiple servers, each with standby capability? Or do you set up server clusters?
If the latter approach is appealing, you have to decide whether to use your existing servers, buy new servers and cluster them together yourself, or buy preconfigured clusters. Then you have to run them on operating system software you can trust.
We significantly narrowed down these questions for the purpose of conducting this test by using a cluster of NetWare 5.1-powered servers. The remaining questions were simple:
First, how hard is NetWare Cluster Services to install and use? Second, should you roll your own cluster, or buy a preconfigured system, like the one provided to us by Compaq Computer Corp.? And third, does Novell Inc.'s cluster software work in all cases?
Installation and configuration
NetWare 5.1 generally installs easily, albeit slower than previous versions because of Novell's insistence on using the new Java-based graphical user interface.
Mashing four existing NetWare 5.1 servers into a cluster required more work than anticipated. However, the cluster-specific management utilities do require extra configuration considerations, and dealing with the new server licenses is time consuming.
Novell now includes with NetWare a certificate authority with Secure Authentication Services (SAS), primarily for Enterprise Web Server users which was running on our test servers. Yet a known error with older SAS files and the Enterprise Web Server requires several Web Server deletions and reinstallations. Novell has posted information about this problem on its support Web site, so check it out before starting. User-licensing errors also come and go on a seemingly random basis during this setup.
These errors led us to the conclusion that combining existing servers takes more time and trouble than starting from scratch. You also have to factor in that adding a storage-area network (SAN), which is often necessary for shared disk space among clustered systems, raises plenty of other technical considerations and requires software modifications and new hardware.
Installing the NetWare Cluster Services software went fairly smoothly. A Windows 95/98/NT/ 2000 client handles the installation honors after you complete the Novell-recommended upgrade of the network client software and add a new version of ConsoleOne, NetWare 's Java-based management utility.
Clustering setup took less than one hour. After rebooting the servers, each looked for others in the cluster and started coordinated communication immediately.
The ProLiant Cluster for NetWare 5.1 from Compaq skipped these software installation problems. Compaq sends a technician to configure each ProLiant Cluster of this size, and our case was no different.
Little is left out of the Compaq clustering system when delivered. NetWare is installed and the SAN is running, as various NetWare volumes and extra Compaq utilities such as SmartStart and Compaq Management Agents add to the ease of management. The Compaq SmartStart utility handles many hardware details during installation while the agents help administrators monitor the nodes.
Once existing servers reboot and start up as cluster-enabled nodes, the Novell Cluster Monitor screen appears, showing each server in the cluster and a few other details. ConsoleOne includes a cluster object and a screen showing cluster-specific information.
The ConsoleOne cluster policies page is plain but important. Start mode groups the cluster resources (applications and shared disk volumes) from each server into the assigned cluster at start-up. Failover mode tells the resource to automatically move to the next assigned server in case of failure. Fallback mode tells the resource whether or not to migrate back to the original server when it reappears.
A quorum number may be set so cluster resources don't start loading until some or all of the cluster servers are online. A check box on the cluster policies page lets you bypass the quorum rule and load the resources on the first server available. This option makes sense when a server handles the majority of the load and spreads critical applications to other, smaller servers in case of a failure.
Shared volumes must be running and accessible to each NetWare server before starting the cluster installation. Novell has strict rules about placing cluster information on certain disks, but the installation notes explain such details well.
Novell includes templates for cluster resources such as Enterprise Web Server, GroupWise, Oracle Corp.'s 8i and Novell Distributed Print Services. The templates are a good start, but installation still requires editing several text files, including load and unload scripts for resource start-up and shutdown. Cluster-enabled applications must utilize the shared volume to allow other servers to pick up in case of failover or migration. The exception comes for certain applications like GroupWise, which can 't use shared volumes.
Building four new NetWare servers and adding clustering support takes the better part of a day, versus unboxing and starting a pre-built system, which takes very little time. Configuring four existing servers could take less time than starting from scratch, but something unforeseen could always happen to an existing machine that could consume a lot of time. The prebundled cluster also gives you a peace of mind that you haven 't missed a step somewhere during configuration.
Using NetWare Clusters
Most importantly, does NetWare Cluster Services work? Yes, both NetWare clusters worked quite well once configured properly. Servers send keep-alive and watchdog packets across the network to verify that all servers and cluster resources are operating properly. If hardware or cluster-enabled software goes down, the next assigned server in the cluster takes over the stranded applications within a few seconds. Web clients will never know the delay isn 't a typical Internet traffic jam.
Load balancing now implies automatic sharing of application load, and Novell misuses the term slightly. Rather than true load balancing, NetWare Cluster Services make it easier to migrate applications from one server to another without client interruption.
Need to add a new server to the cluster with more horsepower, or migrate cluster applications to the new server with a few mouse clicks rather than an afternoon of work? The Cluster Resource Manager dialog box shifts applications between servers in less than one minute. Need hardware maintenance? Migrate the applications, do the maintenance, then migrate the applications back to their original server - less hassle for you, zero downtime for your clients.
Internal NetWare clients using file and print services require some client software adjustment to use any clustered system, mainly to support swapping from one server to another in case of failure or migration. Nothing serious, but mark these configuration file changes down as another reason to get an automatic software rollout utility, like the ZENworks starter kit Novell includes in NetWare 5.1.
Every network manager knows that getting a system up takes less time than keeping it running, and good support tools help tremendously. It 's hard to tell where the NetWare services stop and the Compaq value-added services begin on the ProLiant Cluster. Each rack-mounted server pulls out on rails to provide access to the PCI connectors. Novell supports hot-plugged PCI slots, as does the Compaq hardware.
Compaq gets the credit for quickly restructuring data when a 9.1G-byte drive was pulled from the SAN during operation. Early RAID systems taxed the server tremendously when rebuilding data from a failed drive, but the ProLiant Cluster barely bumped up the NetWare utilization level.
Web-based Compaq Management Agents cover every server hardware detail from any client with a browser and a password (see graphic, above). On the server console, added utilities include the Compaq Integration Maintenance Utility, Compaq Software Support Utility, Compaq Online Configuration for the Fibre Array and the Compaq Power Subsystem Utility, all indistinguishable from the NetWare utilities.
NetWare Cluster Services offers a variety of options for proper application support during a failure. Applications on one server can go to a second server, or be spread to multiple servers. The same holds true for control over shared NetWare volumes. Each cluster resource can be configured differently from any other resource, if you want to take the time and effort. One server can failover to one server, one can fail to many, many can fail to one, or many can fail to many. This flexibility comes from NetWare, not the hardware.
Quibbles and bits
Perhaps it 's just early in the NetWare Cluster Services product cycle, but the lack of utility support and templates for non-Novell applications are troublesome. NetWare installation and management, even for a relatively small addition like the 1M byte of Cluster Services files on the various NetWare servers, still bounced around between ConsoleOne, Net-Ware Administrator and NWCONFIG.
These three utilities offer competing and overlapping features on one hand, with painful restrictions on the other.
Additionally, NetWare 5.1 makes an outstanding application platform, but couldn't some other, non-Novell applications have templates for load balancing across the cluster?
Our Compaq support team worried about price comparisons between its preconfigured cluster and the cost of adding NetWare Cluster Services to existing servers. "Our solution is not inexpensive," team members said. The Compaq cluster we tested costs $167,110.
Once a company decides its Web site must be available, the expense equation changes. Servers only cost money, but downtime cuts your revenue.
NetWare's reliability lulls some into believing any clone desktop PC can become a server. Yet the first step up, either in horsepower or reliability, illustrates the limits of less-expensive PC servers.
Matching the Compaq 6400R cluster we tested requires four servers capable of supporting four Intel Pentium III XEON processors and up to 4G bytes of RAM.
Each 6400R server has dual power supplies; pull one out and the server never blinks. Hot Plug PCI support allows network cards to be added or removed without taking the server down. Hot-swappable redundant hard disks allow storage to be added or removed any time.
Speaking of storage, the Compaq 4100 SAN that came with our clustered servers pushes hot-swappable storage capacity into the terabyte range. Fibre Channel SANs with high-throughput Ultra/Fast/Wide SCSI-2 drives and controllers stand at the top end of performance, reliability and price charts.
The Intel-based, multiprocessor server market gets more crowded every day.
Compaq made some of the earliest heavy-duty NetWare servers, and its long experience shines. Dell Computer Corp. and IBM Corp. also offer Novell-based server clusters.
The Compaq ProLiant Cluster for NetWare performs very well in the heavy rack enclosure that tucks four powerful servers, a SAN and the attendant controllers and cables for all the above in a sturdy package 2 feet wide, 3 feet deep and almost 4 feet tall. Every support module comes in twos, pulls out while the system stays running, slides smoothly back into place and locks into a single block of solid server.
You must note that the software needed to power this cluster is not included in the base price. A basic NetWare 5.1 license is $1,095 for five users, and $10,745 for 100 users. NetWare Cluster Services software is $4,999 per cluster node no matter whose hardware supports it.
Because you 're going to have to pay for the software either route, you take, adding up the convenience of a complete, ready-to-go cluster with highly available hardware in a single convenient package pushes our vote toward the ProLiant Cluster for NetWare. Adding in the Compaq utilities such as SmartStart and Compaq Management Agents make the vote even more in favor of a ProLiant Cluster.
James Gaskin is a freelance writer specializing in technology. His latest book, "Mastering NetWare 5.1" will soon be available from Sybex. E-mail him at firstname.lastname@example.org