Windows 2000 on the Mainframe
Datacenter Server isn’t just about the software. Its adoption also encompasses hardware and partnerships, mindset and expectations. Here’s what you can look forward to when you enter the glass house.
- By Frank Blando
Sept. 26, 2000 marks the day Microsoft announced the
release of the last member of the Windows 2000 operating
systems family, Windows 2000 Datacenter Server. In the
past when Microsoft released a new OS, it usually meant
new software features; new utilities; a new GUI for management;
and, most likely, more certification exams.
However, with Win2K Datacenter Server, the emphasis
is less on software and more on packaging and a new mindset.
This is Microsoft’s first orchestrated attempt at becoming
a player in the corporate data center environment — the
tough-to-crack “glass house.”
This isn’t to say that the software is identical to Win2K
Advanced Server. There are a few differences: two new
components (Process Management and WinSock Direct); some
raised software limits; removal of most non-Datacenter
HCL-compliant drivers; and built-in Service Pack 1.
Process management is a user-mode, user-interface application
that provides an interface to the Job Object API set.
The Job Object APIs are present on all flavors of Win2K
and provide access to the NT kernel’s class-scheduling
features. Class scheduling is a feature previously found
on high-end proprietary systems. It allows the system
administrator to carve out resources and assign them to
tasks. It also allows resource limits to be placed on
tasks, hence preventing a runaway application from taking
over a system. Anyone could write a UI to Job Object APIs
and make it work on all Win2K installations; but Microsoft
provides one that only works on Win2K Datacenter Server.
WinSock Direct (WSD) is a set of drivers and kernel routines
that allows streamlined WinSock communication over System
Area Network (SAN — though not to be confused with Storage
Area Network). Any applications that use WinSock will
automatically get the performance boost from WSD.
Some of the features of Win2K Advanced Server have different
limits than Win2K Datacenter Server, but those changes
aren’t implemented with software modifications. Rather,
the code implements the limits based on what OS version
it detects. Datacenter Server raises the physical memory
limit from 8G to 64G, the SMP CPU limit from eight CPUs
to 32 CPUs, and the server cluster node limit from two
As I discuss shortly, Datacenter Server has a distinctly
different Hardware Compatibility List (HCL). Microsoft
removed most of the drivers for the hardware that didn’t
make it on the HCL. When compared to Advanced Server,
this reduced the software footprint by about 33M.
Finally, SP1 is built into Datacenter Server so the initial
version of the product should be more stable than the
initial versions of the other Win2K flavors.
Relationship and Process Differences
If the software is basically identical, what makes Datacenter
Server different? For starters, you won’t be able to buy
it! It’ll only be available when shipped with certain
approved (HCL) original equipment manufacturer (OEM) systems.
Furthermore, once you have a distribution kit, it only
installs on the hardware it’s intended for.
But the real difference shows up in how you support the
system. Instead of being left to fend for themselves,
MCSEs administering the system will be part of a large
team that includes the OEM and Microsoft. One Microsoft
requirement is that the OEM offer a specialized support
infrastructure. That includes a priority support phone
number and a Joint Support Team (JST) staffed by employees
of the OEM as well as Microsoft. This ensures that problems
are speedily diagnosed and sent to the correct engineering
team for resolution — without finger-pointing. To top
it off, Datacenter calls are given the highest priorities
by the OEM support teams and Microsoft’s critical problem
resolution (CPR) and quick-fix engineering (QFE) teams.
on the High End
The following companies have announced
intentions to offer support — with hardware
and services — for Windows 2000 Datacenter
||Fujitsu Siemens Computers
|Dell Computer Corp.
Appearing to be at the head of the
release pack are those companies that
have already publicly demonstrated multi-node
failover clustering configurations:
Compaq, HP, Unisys, and IBM. The list,
with links, is available at www.microsoft.com/windows2000/datacenter/howtobuy/
The Datacenter Server HCL is quite different from the
usual Win2K HCL. It includes complete combinations of
systems — called stacks or bundles: server, peripherals,
firmware, system software, and utilities. To get on the
HCL, a maxed-out configuration of the bundle needs to
pass a rigorous Windows Hardware Quality Lab (WHQL) stress
Taking an HCL system and blindly adding a component,
like an NE2000-compatible NIC, will make the system lose
its HCL status — and access to the JST for support. So
once a system is on the HCL, the administrator won’t be
required to blindly apply the latest hot fix or the latest
firmware update before getting support. Rather, the opposite
will happen; firmware updates or hot fixes won’t be applied
to correct a problem unless planned, tested, and approved
by the JST.
For MCSEs who have managed mainframes in a prior life,
the transition will be easy; but for the rest of you,
it’s going to take a while to get up to speed. Since Datacenter
Server specifically targets the 24/7 operation, mainframe
management techniques have to be used. Today, the difference
between a mainframe and non-mainframe system comes down
to how it’s managed. I can have a multi-processor system
on my desktop with just as much power as the average “glass
house” mainframe, but I wouldn’t manage them in the same
way. When the system is purchased, the OEM and Microsoft
provide you the support infrastructure, but — ultimately
— whether the system offers true data center mainframe
services relies on the administrator in charge and how
the system is managed.
The cornerstones of the Datacenter Server computing environment
are application availability (uptime), data integrity,
and security. Uptime and data integrity rely on procedure
and infrastructure. The infrastructure should provide
redundant power feeds, redundant air conditioning, and
adequately trained staff. When sizing a Datacenter Server,
it’s imperative to have the “fort under siege” mentality.
You wouldn’t allow single points of failure on your client
network — what good is an up server if the client can’t
access it? You might need to upsize your system to ensure
infrastructure service availability.
Uptime means that problems can be resolved quickly. So
it’s imperative to have application expertise and access
to and knowledge of good troubleshooting tools (both OS
and application) and be able to fix the problem without
rebooting the server. Change control is also imperative
to provide good uptime. Changes shouldn’t be applied until
thoroughly tested and documented. A good backup should
precede every change. And you need to keep a complete
log for all changes (dates, who, what, how, backup location,
and so on). If a change requires a reboot to take effect,
you wouldn’t apply the change and postpone the reboot;
otherwise problems could go undetected until the next
reboot occurred and you might forget about the change.
In Win2K, Microsoft Cluster Server (MSCS) is still basically
the same as in Windows NT Server 4.0 Enterprise Edition.
It only allows application failover between servers —
no Distributed Lock Manager (DLM), no dynamic load balancing,
no process failover. By increasing the number of nodes
in the cluster, Microsoft allows you to decrease the cost
of consolidating standalone Win2K servers into a Datacenter
Server cluster. You only need to provide one spare system
to back up three production servers. In Win2K Advanced
Server, with a two-node cluster, you need one full spare
server per production server. Datacenter Server clustering
also allows you to increase availability by having multiple
backup servers for a very critical server. One major improvement
is that Microsoft is also releasing a generation of truly
cluster-aware BackOffice applications: Exchange 2000 (you’ll
have to wait for SP1 to support Datacenter Server) and
SQL Server 2000.
Data integrity means fault-tolerance in the storage sub-system
(RAID and hot-spares) and a bulletproof backup procedure.
The procedure must account for data consistency, backup
media rotation, media re-use life expectancy, off-site
media storage and retention, and frequent disaster recovery
testing. The backup sub-system should offer adequate throughput
to back up everything without having to postpone backing
up some data.
Finally, strive for and expect stability. The system
should be sized to handle foreseeable growth and not require
frequent hardware updates. Microsoft requires that Datacenter
OEMs support the hardware for extended periods of time
after they stop making it — a managed end-of-life (EOL)
cycle. So even if you can’t buy additional CPUs or memory,
if your server is sized correctly from the get-go, it
will be supported and able to run your mission-critical
application for much longer than the traditional life
expectancy of a normal server.
Microsoft emphasizes that Datacenter Server can reduce
TCO by allowing server consolidation. In theory, you could
take four Win2K Servers, each with two CPUs and 4G of
memory, and turn them into a Win2K Datacenter Server with
eight CPUs and 16G of physical memory. Be careful that
the savings on management cost and software licensing
don’t translate into lower total uptime.
I hope I’ve managed to provide you with a sense of what
Win2K Datacenter Server is and isn’t. Unlike other flavors
of Win2K, Datacenter Server isn’t just software. It’s
a combination of hardware, software, and partnership.
It’s also about mindset and expectations. And, yes, we
can expect to see a high-availability certification exam
coming from Microsoft! See you at the testing center.