Every now and again, I seem to find myself looking at HP’s ProLiant range of industry standard servers. The technology moves ahead but it’s pretty easy to understand where the various models sit in the range because of HP’s product naming system.

The basic principles have been the same for years – the “BMW” numbering scheme: 1 series, 3 series, 5 series and 7 series:

• 1-series servers are entry level servers, targetted at the SMB and High Performance Computing markets, typically with fewer enterprise features (e.g. hot plug components) on board.
• 3-series servers include HP’s 1U DL360 “pizza box” server and the ever-popular DL380 with 2 sockets and a range of storage and connectivity options.
• 5-series servers are the 4-way machines for high-end appllication workloads, with plenty of internal storage and connectivity capacity.
• The 7-series was discontinued for a while (as HP didn’t have an 8-way server) but, with increasing demands for powerful servers for consolidation/virtualisation, it was re-introduced with a DL785 that competes with other manufacturers’ servers such as the SunFire X4600.

The final digit is either a 0 (for an Intel server) or a 5 (for an AMD server). DL servers are rack-mountable (D for density), with ML for tower/freestanding servers, although some of these can also be converted to rack-mount. Each ML server is numbered 10 lower than its DL equivalent – so an ML370 is equivalent to a DL380.

A couple of years ago, HP launched its c-class blades and each blade server (prefixed with BL) was numbered as for the corresponding DL or ML server, but with 100 added to the model number – so a DL380 equivalent blade is a BL480c (c for c-class).

Finally, there’s a generation identifier (e.g. G5, G6). Each generation represents a step forward architecturally (e.g. a move from Ultra 320 to serial-attached SCSI disks, or the adoption of Intel’s latest “Nehalem” processors).

Once you know the system, it’s all pretty straightforward – and, as HP controls half the market for industry standard x64 servers, hopefully this blog post will be useful to someone who’s trying to get their head around it.

Sun Microsystems would like me to use their x64 servers for my virtualisation platform (instead of the HP ProLiant DL585s that I’m currently using). Many of our conversations have been covered by a non-disclosure agreement so I can’t write much here, but the details of the current Sun Fire and Sun Blade x64 servers are in the public domain – and they are certainly worth a look.

I’ll need some pretty serious convincing to move away from our 100% HP ProLiant Windows server estate, especially as we use HP Systems Insight Manager for hardware monitoring and have had some issues in the past integrating hardware from other OEMs; however, the Sun servers do look pretty good – especially for anyone in the market for an 8-way server, where the Sun Fire x4600 is particularly impressive – I guess if HP had an equivalent box it would be called the ProLiant DL785. Sun also have 2-way servers (that would be positioned to compete with the HP ProLiant DL365) and a blade enclosure that’s broadly similar to the HP C-class blade enclosure, which I wrote about a few weeks back. Strangely though, there is a gap – with no 4-way equivalent to the HP ProLiant DL585. They all look to be pretty well engineered, with extra NIC capacity (4 ports as standard) as well as all the other features that could be expected on a modern server (management processor, redundant hot swap power supplies, separate airflows for components, etc.) and a service console port (something that administrators of Sun SPARC servers will have been used to for a while now). In fact, if I had any concerns, it would be about the delay in bringing new developments to market – for example the largest serial attached SCSI (SAS) hard disk drives current offered by Sun are 73GB, whereas some competitors have 146GB SAS drives available.

Sun are still a small player in the x86/x64 server space – but they are rapidly increasing their market share (revenue up 48% and market share up 0.7% year on year [source IDC]); however it should also be noted that market-leaders HP also saw modest growth over the same period. I’ll watch Sun’s progress with interest, and who knows, maybe soon I’ll be in a position to specify some Sun servers somewhere.

I’ve just spent the day with HP, learning about their StorageWorks EVA SANs and the current ProLiant server roadmap. It was an interesting day, but most of what was discussed can be found on the HP website; however I did pick up some snippets of information that might be useful:

• Firstly, when comparing Intel and AMD figures for the power consumption of their servers – if Intel quote the wattage, they quote the mean value, whereas AMD quote a peak figure – so it’s heard to draw accurate comparisons.
• Secondly, as I reported when I wrote about HP blade servers a few weeks back, 3.5″ Ultra320 SCSI disks are being discontinued in favour of 2.5″ serial-attached SCSI (SAS) disks. The main difference (apart from the smaller form factor) is that SAS disks are switched between lanes (cf. a shared bus with Ultra320), increasing performance in a linear manner with each disk connected to a controller (whereas a shared SCSI channel will typically exhibit a bell-curve in its performance characteristics). Also, the smaller physical size of the disk means that a 10,000RPM 2.5″ disk will provide more-or-less equivalent performance to an similarly specified 15,000RPM 3.5″ disk and that less energy is required to spin it, meaning a lower power consumption (and less heat generated).
• One of the other changes in the server lineup is a general move from PCI-X to PCI Express (PCIe) slots offering improved performance (many servers allow a combination of the two to be specified).
• Finally, the new iLO2 management processors (as well as iLO with firmware v1.82 or later) now support schema-less AD integration and iLO2 has a much-improved remote console, with most of the Java code removed, increasing performance drastically.

There’s no real “story” to any of the above – they are just a jumble of notes that might be useful in understanding where HP (and other vendors) are heading in the industry standard x86/x64 server space.

Over the last few years, I’ve heard a lot about blade servers – mostly anecdotal – and mostly commenting that they produce a lot of heat so for all the rack space saved through their use, a lot of empty space needs to be left in datacentres that weren’t designed for today’s high-density servers. In recent weeks I’ve attended a number of events where HP was showcasing their new c-class blade system and it does look as if HP have addressed some of the issues with earlier systems. I’m actually pretty impressed – to the point where I’d seriously consider their use.

HP’s c-class blade system was introduced in June 2006 and new models are gradually coming on stream as HP replaces the earlier p-class blades, sold since 2002 (and expected to be retired in 2007).

The new c-class enclosure requires 10U of rackspace, which can be configured with up to 16 half-height server blades, 8 full-height server blades or a combination of the two. Next week, HP will launch direct-attached storage blades (as well as new server blades) and next year, they expect to launch shared storage blades (similar to the StorageWorks Modular Storage Array products). With the ability to connect multiple blade enclosures to increase capacity, an extremely flexible (and efficient) computing resource pool can be created.

At the back of the enclosure are up to 10 cooling fans, 6 power connections (three-phase connections are also available), 1 or 2 management modules, and up to 8 interconnect modules (e.g. Ethernet or fibre-channel pass-through modules or switches from HP, Cisco, Brocade and others).

There are a number of fundamental changes between the p-class and c-class blade systems. Immediately apparent is that each blade is physically smaller. This has been facilitated by moving all cooling fans off the blade itself and into the enclosure, as well as by the move from Ultra320 SCSI hard disks to small form-factor serial-attached SCSI (SAS) hard disks. Although the SAS disks currently have reduced storage capacity (compared with Ultra320 SCSI), a 146GB 10,000RPM SAS disk will be launched next week and 15,000RPM disks will be released in the coming months. Serial ATA (SATA) disks are also available, but not recommended for 24×7 operation. The new disks use a 2.5″ form factor and weigh significantly less than 3.5″ disks; consequently they require about half as much power to provide equivalent performance.

HP are keen to point out that the new cooling arrangements are highly efficient, with three separate airflows through the enclosure for cooling blades, power supplies and communications devices. Using a parallel, redundant and scalable (PARSEC) architecture, the airflows include back-flow preventers and shut-off doors such that if a component is not installed, then that part of the enclosure is not cooled. If the Thermal Logic control algorithm detects that management information is not available (e.g. if the onboard management module is removed) then the variable speed Active Cool fans will fail open and automatically switch to full power – it really is impressive to see just how much air is pulled through the system by the fans, which are not dissimilar to tiny jet engines!

Power is another area where improvements have been made and instead of using a separate power supply modele, hotswap power supply units are now integrated into the front of the enclosure. The Thermal Logic system will dynamically adjust power and cooling to meet energy budgets such that instead of running multiple supplies at reduced power, some supplies are run close to full capacity (hence more efficiently) whilst others are not used. If one power supply fails, then the others will take up the load, with switching taking around 1ms.

Each blade server is a fully-functional HP ProLiant industry standard server – in fact the BL model numbering system mirrors the ML and DL range, adding 100 to the DL number, so a BL480c blade is equivalent to a DL380 rack-mount server (which itself adds 10 to the ML number – in this case an ML370).

Looking inside a blade, it becomes apparent how much space in a traditional server is taken up by power and cooling requirements – apart from the disks at the front, most of the unit consists of the main board with CPUs and memory. A mezzanine card arrangement is used to provide network or fibre-channel ports, which are connected via HP’s Virtual Connect architecture to the interconnect modules at the rear of the enclosure. This is the main restriction with a blade server – if PCI devices need to be employed, then traditional servers will be required; however each half-height blade can accommodate two mezzanine cards (each up to 2 fibre-channel or 4 Gigabit Ethernet ports) and a full-height blade can accommodate three mezzanine cards. Half-height blades also include 2 network connections as standard and full-height have 4 network connections – more than enough connectivity for most purposes. Each blade has between 2 and 4 hard disks and the direct attached storage blade will provide an additional 6 drives (SAS or SATA) in a half-height blade.

One of the advantages of using servers from tier 1 OEMs has always been the management functionality that’s built in (for years I argued that Compaq ProLiant servers cost more to buy but had a lower overall cost of ownership compared with other manufacturer’s servers) and HP are positioning the new blades in a similar way – that of reducing the total cost of ownership (even if the initial purchase price is slightly higher). Management features included within the blade include the onboard administrator console, with a HP Insight display at the front of the enclosure and up to two management modules at the rear in an active-standby configuration. The insight display is based on technology from HP printers and includes a chat function, e.g. for a remote administrator to send instructions to an engineer (predefined responses can be set or the engineer can respond in free text, but with just up, down and enter buttons it would take a considerable time to do so – worse than sending a text message on a mobile phone!).

Each server blade has an integrated lights out (iLO2) module, which is channelled via the onboard administrator console to allow remote management of the entire blade enclosure or the components within it – including real-time power and cooling control, device health and configuration (e.g. port mapping from blades to interconnect modules), and access to the iLO2 modules (console access via iLO2 seems much more responsive than previous generations, largely due to the removal of much of the Java technology). As with ML and DL ProLiant servers, each blade server includes the ProLiant Essentials foundation pack – part of which is the HP Systems Insight Manager toolset; with further packs building on this to provide additional functionality, such as rapid deployment, virtual machine management or server migration.

The Virtual Connect architecture between the blades and the interconnect modules removes much of the cabling associated with traditional servers. Offering a massive 5Tbps of bandwidth, the backplane needs to suffer four catastrophic failures before a port will become unavailable. In addition, it allows for hot spare blades to be provisioned, such that if one fails, then the network connections (along with MAC addresses, worldwide port numbers and fibre-channel boot parameters) are automatically re-routed to a spare that can be brought online – a technique known as server personality migration.

In terms of the break-even point for cost comparisons between blades and traditional servers, HP claim that it is between 3 and 8 blades, depending on the connectivity options (i.e. less than half an enclosure). They also point out that because the blade enclosure also includes connectivity then its not just server costs that need to be compared – the blade enclosure also replaces other parts of the IT infrastructure.

Of course, all of this relates to HP’s c-class blades and it’s still possible to purchase the old p-class HP blades, which use a totally different architecture. Other OEMs (e.g. Dell and IBM) also produce blade systems and I’d really like to see a universal enclosure that works with any OEM’s blade – in the same way that I can install any standard rack-format equipment in (almost) any rack today. Unfortunately, I can’t see that happening any time soon…

Last week I wrote about the VMware infrastructure that I’m trying to put in place. I mentioned that my testing has been based on HP ProLiant DL585 servers – each of these is equipped with four dual-core AMD Opteron 8xx CPUs and a stack of memory. Half of the initial infrastructure will use new DL585s and the intention is that implementing these servers will release some recently-purchased HP ProLiant DL580G3s for an expansion of the infrastructure. Because the DL580G3 uses an Intel Xeon MP (formerly codenamed Paxville MP) processor, the difference in processor families requires a separation of the servers into two resource pools; however that’s not the real issue. My problem is justifying to an organisation that until now has exclusively used Intel processors that AMD units provide (as my CTO puts it) “more bang for our buck”.

The trouble is that the press is full of reports on how the new Intel Xeon 51xx CPUs (formerly codenamed Woodcrest) out-perform AMD Opterons, where AMD has been in the lead until now; but that’s in the 2-processor server space and I’m not hearing much about 4-way units.

All of this may change tomorrow as, at today’s VMware Beyond Boundaries virtualisation roadshow, Richard Curran, Director of Marketing for the Intel (EMEA) Digital Enterprise Group, hinted about an impending announcement; however an HP representative expressed a view that any new CPU will just be to plug the gap for a few months – the real performance boost will come in a few months time with the next generation of dual-core multiprocessor chips (in the same way that the Xeon 50xx chips, formerly codenamed Dempsey, preceded the 51xx Woodcrest).

Leaving aside any other server vendors, I need some direction as to which 4-way server to buy from HP. HP ProLiant DL580G3s would allow me to standardise but the newer HP ProLiant DL580G4s are more powerful – using the Xeon 71xx chips (formerly codenamed Tulsa) with Intel VT virtualisation support – and, based on list price, are significantly less expensive. Meanwhile, HP’s website claims that ProLiant DL585s are “the best performing x86 4-processor server in the industry” and they cost slightly less than a comparably-specified DL580G4 (again, based on list price), even before taking into account their lower power consumption.

Speaking to Intel, they (somewhat arrogantly) disregarded any reason why I should chose AMD; however AMD were more rational, explaining that regardless of the latest Intel benchmarks, an Opteron is technologically superior for a two main reasons: the hypertransport connection between processor cores; and the integrated memory controller (cf. Intel’s approach of using large volumes of level 3 cache), although the current generation of Opterons only use DDR RAM. Crucially though, AMD’s next-generation dual-core Opterons are socket-compatible with the forthcoming quad-core CPUs (socket F) and are in the same thermal envelope – allowing for processor upgrades – as well as using DDR2 memory and providing AMD-V virtualisation support (but in any case I’ll need to wait a few months for the HP ProLiant DL585G2 before I can buy a socket F-based Opteron 8xxx rack server from HP).

As my virtualisation platform is based on VMware products, I asked VMware which processor architecture they have found to be most performant (especially as the Opteron 8xx does not provide hardware support for virtualisation; although there are doubts about whether ESX Server 3.0 is ready to use such technology – I have read some reports that there will be an upgrade later). Unsurprisingly, VMware are sitting on the fence and will not favour one processor vendor over another (both AMD and Intel are valued business partners for VMware); of course, such comparisons would be subjective anyway but I need to know that I’m making the right purchasing decision. So I asked HP. Again, no-one will give me a written opinion but two HP representatives have expressed similar views verbally – AMD is still in the lead for 4-way servers, at least for the next few months.

There are other considerations too – DL580s feature redundant RAM (after power and disk, memory is the next most likely component to fail and whilst ECC can guard against single-bit failures, double-bit failures are harder to manage); however because the memory controller is integrated in each CPU for an AMD Opteron, there is no redundant RAM for a DL585.

Another consideration is the application load – even virtualised CPUs are perform differently under different workloads: for heavily cached applications (e.g. Microsoft SQL Server or SAP), an Intel architecture may provide the best performance; meanwhile CPU and memory-intensive tasks (e.g. Microsoft Exchange) are more suited to an AMD architecture.

So it seems that it really is “horses for courses” – maybe a split resource pool is the answer with one pool for heavily cached applications and another for CPU and memory-intensive applications. What I really hope is that I don’t regret the decision to follow the AMD path in a few months time… they used to say that “nobody ever got fired for buying IBM“. These days it seems to be the same story for buying Intel.