PowerFrame Enterprise Servers
The Tricord Enterprise Servers are mighty big boxes. They're so big that,
for shipping, they require specially designed crates with padded feet.
In each server's almost 4' tall cabinet, you can cram eight CPUs, up to
3.25GB of main memory, and nine half-height drives. The interior is shaped to
duct air past critical high-heat components, and three redundant power supplies
with 12-volt fans in each module pull air through. Still, wherever you set up
the Tricord server, make sure you have adequate cooling, because these units
generate a lot of heat. A systems engineer accompanies each new system to help
set up and make sure the environment can handle the server.
Big Box, Big Features
The Tricord PowerFrame is not your typical PC server. It almost classifies
as a mainframe or minicomputer--only it consists of standard PC and Intel
components.
With starting prices of $70,000 for these machines, Tricord does not aim at
the small workgroup server market. Instead, typical installations are for
enterprise and mission-critical applications (such as Internet Service
Providers--ISPs), where fault tolerance and availability are key issues. As a
reflection of this focus, Windows NT is the operating system of choice for more
than 20% of Tricord's total new system sales.
The PowerFrame can hold up to eight 166MHz Pentium CPUs (NT 3.51 and 4.0
both scale up to four CPUs right out of the box, but an OEM version of NT is
necessary if you want to run five to eight CPUs), each with its own 2MB Level 2
cache module. The CPU-to-memory bus is part of the main 64-bit/ 33MHz system
bus, which Tricord has dubbed the PowerBus. The PowerBus can reach
267MB-per-second (MBps) transfer rates. This bus also couples the CPU and Cache
Subsystem (CCS, which uses its own 64-bit/66MHz internal data bus) to the other
major system components. Each board holds two CPUs, and a system can have up to
four CCS modules. Of the 10 total slots on the PowerFrame I reviewed, five are
taken by the Intelligent Communications Subsystem (the ATM PowerLink, an
optional 155Mbits-per-second--Mbps--fiber-optic ATM interface with its own
processing hardware), the Intelligent Storage Subsystem (ISS, multichannel SCSI
buses), the Main Memory Subsystem (MMS), the PCI Bridge Subsystem (PBS, two PCI
buses, one EISA bus, one peripheral bus), and the Intelligent Management
Subsystem (IMS, hardware monitoring and management). This architecture lets each
subsystem arbitrate its bus usage via the System Bus Arbiter, with bus
locking by the active device. This approach avoids wasting valuable time
polling other subsystems.
All components except the ATM PowerLink are standard. A base configuration
includes one CCS, one ISS board, the MMS (with the amount of memory you need),
the PBS, and the IMS. Each CCS board (you can have up to four) holds one or two
166MHz Pentium CPUs with cache. The necessary subsystems take five slots, and
you can fill five other slots in any combination of CCS and ISS boards. The CCS
is designed for NT's symmetrical multiprocessing (SMP--although the CCS also
supports asymmetrical multiprocessing for other OSs). The large, high-speed
Static RAM (SRAM) Level 2 cache dedicated to each CPU significantly boosts the
performance of multithreaded and SMP-enabled, 32-bit NT applications such as
databases (SQL Server, Oracle Server) and messaging (Exchange, Notes). The
PowerFrame's ability to use up to eight CPUs makes it a strong contender in
enterprise NT environments where scaleability to high-end applications and heavy
user loads are important.
The ISS is Tricord's primary claim to fame, and the PowerFrame can support
up to six of these four-channel, fast-and-wide-and-deep, differential SCSI-2
controllers (two-channel versions are also available). Deep SCSI uses four bits
for device addressing instead of three, so one ISS controller card can address
up to 60 drives, with 15 drives on each channel (the last address is reserved
for the controller). One PowerFrame server can support up to 201 drives, so you
can have up to 2.1TB of disk storage with today's technology! The ISS is
hardware accelerated for RAID levels 0, 1, 4, 5, and 10 (mirrored stripe sets,
a.k.a. RAID 6), with disk hot-sparing (the SCSI backplane supports disk
hot-swapping) and background disk rebuilding after failure and replacement. (For
more on performance under different RAID levels, see the sidebar, "RAID
Performance and NT: Configuring an Enterprise Server.") The ISS board
includes a battery-backed 8MB controller cache, so if system power fails, you
don't lose crucial data, even if it wasn't written to disk. Also, if the
controller fails and the system goes offline, you can remove the card, transfer
the cache module to a new controller card, reinstall it, and restart the system
to begin recovery procedures. You can be confident that data not already flushed
from the cache out to disk was not lost (this capability doesn't include data in
main memory).