HP may have taken everyone by surprise with its swift entry into the blade server market in July 2002 but IBM took the honours as the first to squeeze a Xeon processor into these slim-line systems. Launched in September last year the BladeCentre originally came equipped with a single Xeon processor but still managed to deliver a density of 84 processors per industry standard rack. This was no different to the densities that can be realised with standard 1U rack servers but IBM reckoned at the time that its BladeCentre was a more cost effective alternative to shoving 42 servers in a rack. The latest BladeCentre ups the ante by delivering dual Xeon equipped server blades and with fourteen slots to its mighty 7U chassis it offers a density of 168 processors per rack – 56 more than HP’s BL20 p-Class. Build quality is up to the usual high standard we expect from IBM whilst plenty of fault tolerant components are also on the menu. Two hot-swap power supplies are provided as standard with room for two more at the rear and up to four, quad-port Layer 2 Ethernet switch modules can be fitted or mixed with fibre channel switches. A module with KVM switch and Ethernet port handles local and remote management and this can be protected with a second redundant module. Cooling is very well handled throughout the system and the chassis is equipped with two gargantuan blower fans making the power up sequence a truly unforgettable experience. The CD-ROM and floppy drives plus two USB ports are fitted in the chassis’ front panel and buttons on the front of each blade allow you to decide which one can access these. For server deployment tools, HP is a hard act to beat but IBM comes a close second with its Remote Deployment Manager (RDM). A small patch needs to be applied first but with this in place RDM will display all blades attempting a network boot that are awaiting OS deployment. You can use different profiles to manage a wide range of OS settings and RDM supports deployment of PowerQuest Drive Image or its own CloneIt disk images which can be used to push an OS onto selected blades. General systems management and monitoring is handled by IBM’s Director which requires a small agent loaded locally. This provides plenty of operational information about each blade and events or component failures can be linked to an extensive range of alerts and warnings. Overall, the RDM and Director partnership does provide plenty of administrative tools but we still prefer HP’s Altiris software package which is a lot slicker. Physically, the HS20 blades are very well built coming enclosed in a heavy steel shell with an easily removable lid and the price for the review system includes four blades each equipped with a single 2.4GHz Xeon processor. The second processor socket sits alongside and behind are four DIMM sockets of which two are occupied by 512MB of PC2100 memory modules expandable to 8GB. Storage options are radically different to the BL20 p-Class as IBM opted to go for two 2.5in. hard disks mounted on the blade whereas HP chose to fit dual 3.5in SCSI drives in hot-swap bays in front of each blade. The main differences are that hardware IDE RAID is not supported in the BladeCentre and if this is a requirement you must install the optional hot-swap Ultra320 SCSI expansion unit which requires one of the blade slots. The network connection for each blade is handled by dual on-board Broadcom NetXtreme Gigabit adapters and these are ported through to separate switch modules when the blade is placed in the chassis. Each blade has its own local power button but the management module’s browser interface provides plenty of remote access to each component. There’s little between the BladeCentre and the BL20 p-Class for overall build quality although IBM loses out in the power and management departments as HP’s separate chassis-based supplies look better suited to enterprise applications and its management software bundle is also more sophisticated. However, if you don’t need mainframe quality redundancy then the BladeCentre is a far less costly alternative and delivers one of the highest Xeon processing densities currently available.


The blade server market currently offers plenty of choice in processing density, processor type, storage and manageability. RLX recently announced dual Xeon blades but these have yet to materialise making HP’s more costly BL20 p-Class IBM’s closest competitor so the decision rests on the requirements for processing density, power fault tolerance and, of course, budget