Apr. 07, 2000 (InternetWeek - CMP via COMTEX) -- most of us agree that Novell
generally leads Microsoft in implementing new server technologies. But one area
where it has lagged behind until recently was server clustering.
Microsoft dished out this ability, albeit in limited format, some two years ago
in the form of its Wolfpack services and has since steadily improved the
product. Though Novell debuted similar functionality at about the same time,
it's been very quiet about this technology-until the recent release of NetWare
Cluster Services version 1.0 (NWCS), that is.
In an interesting spin, Novell has aimed a little higher than Microsoft in terms
of functionality. Where Wolfpack is strictly a fail-over and light
load-balancing tool, NWCS seeks to mirror this functionality and combine it with
the ability to build SAN-like storage clusters in addition to file server
clusters.
We tried to test NWCS in its version 1.01 configuration, with the NWCS 1.01
support disk that allows the software to run on NetWare 5.1 as well as NetWare
5.0. Unfortunately, though this software was due in March, we were still unable
to get it in time for testing. In addition to lending support for NetWare 5.1,
the 1.01 version is also supposed to provide the ability to cluster up to 32
nodes within a single cluster, as opposed to the eight nodes that represent the
present ceiling. That's way ahead of what Microsoft has delivered on Windows NT
to date, though we'll wait for the actual delivery of Windows 2000 Data Center
to make the final comparison.
Getting back to NWCS' SAN orientation, we were originally a bit disappointed
with this feature, but we bucked up somewhat once we had it running. What Novell
calls a storage area network, the rest of us call a shared storage volume.
Admittedly, it's well executed, but a true OS- and application-independent
storage resource this isn't.
Basically, by installing NetWare Storage Services over TCP/IP, NWCS gains the
ability to mount and dismount storage volumes much more quickly and smoothly
than standard NetWare volumes, especially across multiple servers or attached
storage devices, such as fibre channel or RAID enclosures. By sharing these
volumes across all the servers in the cluster and offering the ability to
quickly mount or dismount new volumes, Novell has neatly combined centralized
storage management with server failover and load balancing. It may not
technically be a SAN, but it's still a sweet combination.
Running NWCS is not a trivial task. While the NWCS software isn't the most
complex part of the equation, it can easily become so if you're not familiar
with NetWare 5 or haven't read the NWCS documentation.
The toughest part for us was installing NetWare 5 on four near-identical Compaq
ProLiant 1600 rack-mount machines-two we had and two we had to "borrow" from
reluctant friends. As these machines had no software distribution capability, we
wound up installing NetWare 5 manually on each one-that's one weekend we won't
get back. As we also didn't have an external device dedicated to storage (such
as Compaq's much-sought-after StorageWorks enclosure), we had to dedicate one
server's array as the central shared storage medium. That may have been a
let-down for us, but it's a feather in Novell's cap that the system is flexible
enough to allow this.
At this point, you can install NetWare Cluster Services, though you'll need to
remember to configure volumes in the shared storage system with NetWare Storage
Services instead of standard NetWare. The other prerequisite is that the shared
storage system must hold dedicated volumes for each server in the cluster prior
to installation. Additionally, you'll need a connected manager's console machine
running Novell's Client 32 and the ConsoleOne management software. While we
chose an IBM ThinkPad 600 running Windows 2000 Professional for this purpose,
other console platforms might be supported, given that ConsoleOne is a 100
percent Java application.
Once you've got this basic clustering configuration set up, you can decide which
services and applications should be cluster-enabled. This is by far the most
tedious part of NWCS as there are special instructions, not just between
services and applications in general, but differences between specific
applications as well. For example, Novell dictates that certain applications,
such as its own GroupWise messaging platform, be stored in shared volumes to
help with fault-tolerance, but that these volumes not be cluster-enabled.
Fully cluster-enabling a volume means it becomes its own NDS object, complete
with a dedicated IP address. To administrators familiar with NetWare and NDS,
this isn't very complicated-just a bit on the boring side. You just need to be
sure to check the docs or with Novell for specific requirements before
attempting to cluster specific applications.
Once you have cluster-enabled an application, it, too, becomes an NDS object,
complete with its own IP address. The object also needs to be configured with
cluster-specific information, such as which servers in the cluster will access
it and how it needs to be moved in case of primary server failure. Again, this
sounds complex on paper, but it's exactly the kind of flexibility that cluster
managers are looking for, and it's all done straight through the ConsoleOne
interface.
While it still lacks advanced support for load balancing at an application
level, NWCS is still quite a bit ahead of what anyone else is offering in the
operating system space. You don't need a dedicated high-speed transport
mechanism between the servers in the cluster. The whole thing can be configured
virtually over the existing network, although it can support a separate ring if
one is deemed necessary. Also, you don't need identical hardware-or even
hardware certified by Novell. Almost anything that can run NetWare 5.x can run
NWCS.
That alone is enough to make the software worth its weight in gold. And once
NWCS 1.01 is released, you'll be able to cluster up to 32 separate nodes--eight
times what Microsoft is presently slating for Windows 2000 Data Center, which I
haven't even seen in beta.
While it still may not be enough to put a dent in the Win2000 marketing
juggernaut, NWCS is an absolute must for network administrators running NetWare
5 in high-availability configurations.
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