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PCIe 3.0 expansion and support for PCIe SSD storage
iDRAC7 remote management plus Dell Lifecycle Controller 2.0
Choosing the right processor/memory combination can be complex
Two processors in 2U (2P2U) is the big-selling sweet spot as far as server vendors are concerned, making the PowerEdge R720 from Dell a significant new product. It's also the first PowerEdge to ship with Xeon E5-2600 processors, based on Intel's latest Sandy Bridge EP architecture and the first of Dell's so-called 'twelfth-generation' (12G) PowerEdge servers, which major on enhanced management as well as performance and availability.
So, an important new server — with yet another new twist in the guise of two different models to suit different markets.
The PowerEdge R720 is available with eight 3.5in. drive bays or — as reviewed here — sixteen 2.5in. bays
For our review we were sent the standard R720, which is at customers looking to service high-performance computing and virtualisation workloads. This can be specified with either eight 3.5in. drive bays or, if you prefer 2.5in. disks, an impressive sixteen bays — as on the chassis we were sent. If storage is a major consideration, there's also the R720xd, which can accommodate up to 26 2.5in. disks, mostly at the front but with two cunningly tucked away at the rear of the unit.
Storage apart there's little to choose between the two models, and both are 2U with the same choice of redundant power supplies. Ours were platinum-rated 750W units, but 495W and 1100W variants are an option, plus there's also a new DC power supply if preferred.
Of course, power supply is in part dictated by the processors configured, with a mind-boggling sixteen members of the Xeon E5-2600 family on offer here. That includes 4-core and 6-core chips with a variety of options in terms of cache, functionality and power requirements.
For our tests Dell supplied the 8-core E5-2680, clocked at 2.7GHz and equipped with 20MB of cache. Just one away from being the fastest of the E5-2600 family, the E5-2680 also features Turbo Boost 2.0, which allows cores to be independently speeded up to cope with peaks in processor demand. The E5-2680 also has the full set of 8.0GT/s QPI links. On the downside, it can pull up to 130W when pushed hard and, as such, is best suited to processor-intensive HPC and virtualisation workloads where energy efficiency is a secondary consideration.
Our review unit had two 8-core Xeon E5-2680 processors and 64GB of DDR3 RAM; with 24 memory slots, the system can accept up to 768GB using 32GB DIMMs
Our server had two of these processors, complete with surprisingly compact heatsinks, neatly sandwiched between 24 memory slots on the densely populated R720 motherboard. That's six more slots than the PowerEdge R710 could handle — although most of ours were filled by blanks, the test server having a 'mere' 64GB DDR3 memory to play with. However, with that many slots and support for 32GB DIMMs you can go for as much as 768GB. Assuming, of course, you have the budget to support it and the applications to use it.
There's also support for Load-Reduced DIMM (LRDIMM) technology and memory speeds of up to 1600MT/s, plus lots of RAS (Reliability, Availability, Serviceability) features such as memory mirroring, sparing and thermal throttling. Some care is needed when it comes to the combinations that are allowed, though. Indeed, deciding just what kind of memory to go for and how much is becoming something of a fine art, with expert help a must-have if you're unsure.
Storage is getting quite involved too, starting with the usual extensive choice of SATA/SAS and SSD drives, plus a number of controllers to match. Additionally you can specify up to four Dell Express Flash PCIe solid-state drives (on the R720 model only, not the R720xd); these hot-plug, front-access SSDs deliver fast storage without the processor overheads of conventional SSDs.
That aside, the most basic option when it comes to storage is a software-based PERC S110 designed to use the on-board SATA interface to support RAID 0, 1, 5 and 10 arrays. However, with this budget arrangement you're limited to just four 3.5in. 3Gbps SATA disks. It's also a Windows-only solution, which means that most customers are likely to opt for something more capable.
Internal and external HBAs are both available here, including the new PERC H710P fitted on the review system, which can be used to implement fast internal SAS arrays without using up one of the PCIe expansion slots. Ours was cabled to a modest set of five 300GB disks spinning at 10,000rpm, but this 8Gbps card can handle up to 32 SATA, SSD or SSD disks if needed. It also comes with 512MB of battery-backed cache and provides support for RAID 0,1, 5 and 6 protection.
The PowerEdge R720's Dell Select Network Adapter fits into a custom connector, freeing up a PCIe slot
For networking connectivity, our server had a set of four Gigabit network interfaces, located on a Dell Select Network Adapter fitted into a custom connector rather than a PCIe expansion slot. Dual-port 10GbE alternatives are also available as an alternative, based on Broadcom or Intel chips and with or without TCP and iSCSI offload engines.
Whatever you go for, this arrangement leaves all seven PCIe slots free for further expansion, all with support for the latest PCIe 3.0 technology. These slots can be used for a variety of purposes, including the addition of multi-core GPU accelerator cards from NVidia and AMD with room for two of these double-width adapters. Do not assume that you can get an immediate performance boost from GPU cards, however, as specialist software is required to exploit the processing capabilities they provide.
For virtualisation there's an embedded hypervisor option in the form of a dual SD card module on the R720, the second card providing redundancy should one of the hypervisors fail.
Dell's upgraded iDRAC7 remote management controller offers an improved web interface and is easier to upgrade from the Express to the Enterprise version
Finally there's a comprehensive stash of management features, including version 2 of Dell's Lifecycle Controller, which HP looks set to emulate on its Gen 8 servers, and an upgraded iDRAC 7 remote management controller. This last option features a much-improved web interface with easier access to important data and enhanced power monitoring and management features. It's also easier to upgrade from the basic Express implementation to the full iDRAC 7 Enterprise edition with a graphical remote console and virtual media. On previous servers extra hardware was needed; on the R720 all you have to do is buy a licence.
Dell is the first of the tier 1 vendors to ship a Xeon E5 server into the 2P2U space, and we were very impressed with what the R720 has to offer. It performed faultlessly throughout our tests and certainly hits the sweet spot. The competition will have to work hard to match it.