IBM hits sweet 16
- 18 August, 2003 11:40
Sometimes, size does matter. Take servers. Some applications - Web hosting, file/print, domain control, firewalls - don't require a huge amount of horsepower or the utmost in high-availability hardware because it's easy to build clusters.
But when it comes to more robust challenges - high-end transaction processing, messaging, database serving, data warehousing - you want big, bigger, biggest, such as IBM's eServer xSeries 445, which replaces the x440 that first shipped in August 2002.
In the realm of x86-based servers, I haven't yet found an Intel-based machine that's as powerful, resilient, and scalable as the eight-processor 2.8GHz Xeon MP (multiprocessing)-based x445. Or rather, as resilient as two of those 4U (7in) rack-mount boxes, which is what IBM sent for review: Plug them both together with a special cable and change a BIOS setting, and suddenly you have a single 16-way server. Now, that's scalability, although it doesn't come cheaply at about $US70,000 for each fully laden, eight-way server.
(Microsoft also takes a pound of flesh. IBM preinstalled Windows Server 2003 Datacenter Edition, for which a 16-processor licence costs $US54,555.)
There's a lot to admire about the x445 server, beyond the instant-16-way trick. IBM gives you a choice of using the slower but most robust Xeon MP processor, which has huge 2MB L3 cache ideal for massive database access, or the faster but wimpy Xeon DP (dual-processing) processor, which lacks the L3 cache but has faster clock and bus speeds suitable for CPU-based tasks, such as graphics visualisation or serving up Web pages. To up the performance, IBM also installs 64MB of memory cache for every two installed processors, using what it calls the XcelL4 Server Accelerator.
It's unique in the market, as far as I can tell. IBM claims to have figured out how to make the x445 work as a four-way server with the far less expensive Xeon DP processor, which is normally limited to two-way configurations. The benefit there is that if all you need is a four-way server, you can get all the robustness of the x445 chassis with the Xeon DP's faster clock. However, the systems I tested used Xeon MP processors.
In many ways, the x445 is comparable to Hewlett-Packard's ProLiant DL740 server, which is also a 4U-high box with eight Xeon processors and many high-availability features. In terms of specs, the boxes are similar, though in some ways HP has IBM beat.
Both servers have dual Gigabit Ethernet ports. The IBM x445 has six hot-swap PCI-X slots while the HP DL740 has eight. Both have onboard Ultra320 SCSI RAID controllers, though the IBM server has two hot-swap drive bays, and the HP server has four. Score one for HP, though IBM does sell a separate enclosure that provides 12 additional PCI-X slots.
IBM differentiates itself with robustness and reliability. The server contains IBM's memory-recovery technology, called Chipkill, which can recover from double-bit memory errors and has optional memory mirroring and hot-add memory capability with Windows Server 2003.
Considering that memory, next to power supplies and rotating media, is a weak spot in any server, Chipkill is a great idea and an improvement over ordinary ECC (error-correcting code) RAM.
HP's RAID memory approach is different: RAM is striped across five memory modules, so that any one can fail without crashing the machine, plus they can be hot-swapped without powering down.
While HP requires you to buy and install 1.25GB of chips to get an effective 1GB RAM, it does offer more resiliency in case of a catastrophic memory failure.
Also tops is IBM's maintainability. The company has updated its Lightpath diagnostic system with a small pull-out console that provides full hardware diagnostics without having to unrack the server, plus LEDs on key hardware components (such as RAM modules, PCI slots, and power supplies) that identify bad parts. There are other little pieces too numerous to mention here. But if I had to bring a dead server back to life or perform routine hardware maintenance, I'd rather repair the x445 than anything else in this class.
Applications from the likes of Oracle, SAP, and PeopleSoft need power, headroom, and servers that don't break. As Big Blue's high-end IBM x86 server, the xSeries 445 is a machine worthy of deployment anywhere you need an eight-way box - with room to grow.
How I tested
Not one, but two - that's how many xServer eSeries 445 servers IBM provided for this review. Both servers were identical, with eight 2.8GHz Xeon MPs, 2GB RAM, and dual 36GB hard drives. Both servers were equipped with Microsoft's new Windows Server 2003 Datacenter Edition.
My testing scenario for these servers focused on three areas: general usefulness and applicability as an enterprise-class server, high availability features within a single-server configuration, and scalability using IBM's unique ability to merge the two machines into a single 16-processor server.
In terms of evaluating general usefulness, the test examined the individual components of the servers with special emphasis on scalability and expandability. During this period, the server ran a standard suite of Microsoft applications. Third-party tools were run on other servers in the lab, particularly NetIQ's Chariot and a 2001 version of Rational's now-obsolete SiteLoad software, to generate traffic across the Gigabit Ethernet interface and to stress the systems while exercising the high-availability features.
Unfortunately, unlike with the RAID Memory in Hewlett-Packard's ProLiant DL740, it's difficult to test IBM's Chipkill fault-tolerant RAM technology short of having known defective memory chips, which were not available for this test. So, I was unable to verify the effectiveness of this key server feature through hands-on testing. However, I generated other errors to activate the LightPath diagnostics, such as jamming a cooling fan and inserting a known defective PCI card.
I tested the 16-way dual-server hookup by following IBM's documented procedure for linking the two servers, and verifying that all components and functionality were present after the merger - that, in effect, the two x445 boxes became one server that offered all the combined features of both servers, including processors, memory, expansion, and storage. It's an impressive feat.
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