Dell PowerEdge M-Series blade server review

After a couple of false starts, Dell appears finally to have a blade server platform to rival those from HP and IBM. Moreover, in the past few months, Dell has extended its M-Series Blade Server family, adding yet more server options plus flexible new I/O modules developed in conjunction with Cisco and Brocade.

Dell has also updated its management interface, and with the offer of exclusive access to Dell's proof-of-concept lab in Ireland, we thought it time to investigate exactly what the M-Series is all about.

The first thing we learned was that the 'M' in M-Series stands for modular, with a single 10U chassis - the PowerEdge M1000e - at the heart of the product.

Capable of accommodating all of the current M-Series blades and future additions for at least the next few years, it's a compact and very smart piece of kit. Built to the usual Dell high standards it has room for eight full-height blades, or 16 half-height servers for customers wanting maximum processor density.

The blades plug into the chassis from the front into a passive single-board mid-plane. With no electronics to go wrong, this makes for a very robust and reliable arrangement. Moreover, the Dell engineers were at pains to point out the use of female connectors on the mid-plane and male on the blades so that, if a pin gets damaged, it affects only that single blade rather than the entire mid-plane.

The mid-plane, in turn, connects the blades to power, a plug-in management controller and a variety of I/O modules, about which more shortly.

The blades come in a range of specifications to suit every application from simple web server farms, through scalable virtualisation to high-end application and cloud hosting. Intel-and AMD-based blades are both available, and the PowerEdge M610 (from £1,837 ex VAT) is a popular choice across a wide range of applications and a typical starting point for many deployments.

A half-height blade, the M610 sports dual CPU sockets to take quad-core or six-core Xeon processors, which means up to 12 cores per server backed by up to 192GB of DDR3 memory on a very compact, hot-pluggable board. There's even room for a couple of 2.5in hot-swap drives, with a choice of SATA/SAS or SSD devices plus an optional RAID controller.

Our test system was populated with six M610 blades alongside two full-height M910 blade servers, the latter of which are available from £5,021 (ex VAT).

A recent addition to the range, the M910 is a real powerhouse of a server, capable of accommodating four Xeon 7500 multi-core processors and a huge 512GB of RAM. The same redundant hypervisors found on PowerEdge rack servers are also to be had on these and other blades, together with the same choice of iDRAC management controllers and Dell's unique Lifecycle Controller.

Between these two extremes come various others, including two- and four-socket AMD blades, including the dual-socket M805 from £2,781 (ex VAT), which can accommodate quad-core Opterons and up to 128GB of memory.

The M-Series, however, is about a lot more than just blades, as we discovered when we started poking around at the back, where the system management, cooling, power and I/O modules are located.

Starting at the top, there are slots for two Chassis Management Controllers (CMCs) and an integrated Avocent KVM-over-IP switch. Just one CMC is supplied as standard, as on the unit we tested, but a second can be added for extra fault tolerance (£310 ex VAT), an option most customers go for. KVM remote control is optional but, again, commonly specified.

Lower down, the nine cooling fans are evenly spaced in the centre of the unit, interleaved with the I/O modules, with the power supplies all at the bottom. Like the fans, the power supplies are hot-swappable. Three are required to run a fully loaded enclosure and six for a redundant setup. The management controller can switch supplies off when not required.

The nine fans can be quite noisy, but were hardly noticeable in a datacentre like the one we were in. Moreover, Dell has carefully balanced the airflows to minimise cooling requirements with special plug-in baffles for empty blade slots to maintain correct airflow on a partially populated chassis.

Finally, there are the I/O modules, which is where things start to get a little complicated, but at the same time very interesting, as these modules really help the M-Series to stand out from the crowd.

Dell's idea was to do away with the need for separate network switches and incorporate them into the same chassis used to hold the blade servers. To this end the I/O ports on the blades connect directly via the mid-plane to the associated I/O modules (Ethernet, Fibre Channel or InfiniBand) which, in turn, are equipped with external ports to connect to the customer's communication and storage networks.

Each server has access to up to three so-called I/O fabrics comprised of three redundant pairs of I/O modules. The first of these is connected to the Ethernet LAN-on-motherboard (LOM) interface built onto the blades, while access to the other two requires optional mezzanine cards on each one, with a choice of cards to support Fibre Channel and InfiniBand as well as additional Ethernet connectivity.

The most basic I/O modules (known as Pass-Through modules) simply allow the blades to be cabled to external switches. The 1Gbit/s Pass-Through module, which has 16 UTP ports, or the new 10GBit/s Pass-Through for use with blades with 10Gbit/s interfaces. Externally, this card has 16 ports for optical transceivers, allowing for maximum throughput with minimal cabling.

Pass-through modules are also available for Fibre Channel, while higher up the food chain come Ethernet, Fibre Channel and InfiniBand switch modules, which aren't always cheap, but really do make a difference when it comes to the space required.

A variety of switch modules are available, many from Dell itself but also from Cisco, which has ported its Catalyst Ethernet switches to the M-Series format (from £2,360 ex VAT per switch). Also available are modules from SAN specialist Brocade for Fibre Channel. A typical Brocade M5424c 8GB module sells for £3,712 (ex VAT) per switch.

Another newcomer to the range is a converged I/O module, the M8428-k (£10,400 ex VAT per switch), integrating 10Gbit/s Fibre Channel over Ethernet (FCoE) with 8Gbit/s Fibre Channel on a single device.

As with the blades, the I/O modules are all interchangeable and hot pluggable and can be ordered with varying numbers of external ports. We found we needed to take care with the cabling, but otherwise found adding or changing modules very straightforward.

We were also impressed by an option called FlexAddress, whereby the worldwide name (WWN) identifiers used by Fibre Channel controllers and the MAC addresses of Ethernet and iSCSI can be locked to a specific slot in the chassis, rather than the blade server occupying it.

That way, we were able to swap server blades without having to reconfigure them, making it quicker and easier to handle blade failures and upgrades.

Then there's the recently revamped management interface, hosted by the Chassis Management Controller and accessible via a browser. This we found very easy to navigate, with lots of graphics and online help to enable us to monitor the current status of our blade servers and change their configuration. Power management is particularly well served here, with tools that allowed us to cap power usage and see how efficiently each server was operating.

We were also able to access the iDRAC management controller on each of our blades, giving out-of-band remote access and support for remote virtual storage.

Dell has recently launched an application called Advanced Infrastructure Manager (AIM) to deploy and manage virtual and physical server systems. Specifically tuned for use with the M-Series hardware, we were very impressed with what AIM was able to do, so look out for a separate in-depth review of that soon.

Overall, our time testing the M-Series Blade Server proved to be a good experience, demonstrating the maturity and depth of the Dell solution. Performance is excellent, thanks to the blades deployed, which come ready installed on a new buy.

The I/O side of the equation is also impressive, and particularly flexible with lots of top-notch switching options, making for a product portfolio capable of more than just matching the competition.