I came across a recent post by Chad Sakac (VP, VMware Alliance at EMC) discussing the issue of how vendors drive customer specifications down from broader goals to individual features or implementation sets (I’m sure VCE was not in mind at the time.) When it comes to vendors insist on framing the “client argument” in terms of specific features and proprietary approaches, I have to agree that Chad is spot on. Here’s why:
First, it helps when vendors move beyond the “simple thinking” of infrastructure elements as a grid of point solutions and more of an “organic marriage of tools” – often with overlapping qualities. Some marriages begin with specific goals, some develop them along the way and others change course drastically and without much warning. The rigidness of point approaches rarely accommodates growth beyond the set of assumptions that created the it in the first place. Likewise, the “laser focus” on specific features detracts from the overall goal: the present and future value of the solution.
When I married my wife, we both knew we wanted kids. Some of our friends married and “never” wanted kids, only to discover a child on the way and subsequent fulfillment through raising them. Still, others saw a bright future strained with incompatibility and the inevitable divorce. Such is the way with marriages.
Second, it takes vision to solve complex problems. Our church (Church of the Highlands in Birmingham, Alabama) takes a very cautious position on the union between souls: requiring that each new couple seeking a marriage give it the due consideration and compatibility testing necessary to have a real chance at a successful outcome. A lot of “problems” we would encounter were identified before we were married, and when they finally popped-up we knew how to identify and deal with them properly.
Couples that see “counseling” as too obtrusive (or unnecessary) have other options. While the initial investment of money are often equivalent, the return on investment is not so certain. Uncovering incompatibilities “after the sale” provides for difficult and too often a doomed outcome (hence, 50% divorce rate.)
This same drama plays out in IT infrastructures where equally elaborate plans, goals and unexpected changes abound. You date (prospecting and trials), you marry (close) and are either fruitful (happy client), disappointed (unfulfilled promises) or divorce. Often, it’s not the plan that failed but the failure to set/manage expectations and address problems that causes the split.
Our pastor could not promise that our marriage would last forever: our success is left to God and the two of us. But he did help us to make decisions that would give us a chance at a fruitful union. Likewise, no vendor can promise a flawless outcome (if they do, get a second opinion), but they can (and should) provide the necessary foundation for a successful marriage of the technology to the business problem.
Third, the value of good advice is not always obvious and never comes without risk. My wife and I were somewhat hesitant on counseling before marriage because we were “in love” and were happy to be blind to the “problems” we might face. Our church made it easy for us: no counseling, no marriage. Businesses can choose to plot a similar course for their clients with respect to their products (especially the complex ones): discuss the potential problems with the solution BEFORE the sale or there is no sale. Sometimes this takes a lot of guts – especially when the competition takes the route of oversimplification. Too often IT sales see identifying initial problems (with their own approach) as too high a risk and too great an obstacle to the sale.
Ultimately, when you give due consideration to the needs of the marriage, you have more options and are better equipped to handle the inevitable trials you will face. Whether it’s an unexpected child on the way, or an unexpected up-tick in storage growth, having the tools in-hand to deal with the problem lessens its severity. The point is, being prepared is better than the assumption of perfection.
Finally, the focus has to be what YOUR SOLUTION can bring to the table: not how you think your competition will come-up short. In Chad’s story, he’s identified vendors disqualifying one another’s solutions based on their (institutional) belief (or disbelief) in a particular feature or value proposition. That’s all hollow marketing and puffery to me, and I agree completely with his conclusion: vendors need to concentrate on how their solution(s) provide present and future value to the customer and refrain from the “art” of narrowly framing their competitors.
Features don’t solve problems: the people using them do. The presence (or absence) of a feature simply changes the approach (i.e. the fallacy of feature parity). As Chad said, it’s the TOTALITY of the approach that derives value – and that goes way beyond individual features and products. It’s clear to me that a lot of counseling takes place between Sakac’s EMC team and their clients to reach those results. Great job, Chad, you’ve set a great example for your team!
Given that VMmark is a single node test harness, the difference between rack server and blade server architectures is a non-issue. However, more than just rack vs. blade is going on in this comparison. The Cisco UCS system is being fed by a pair of 10GE converged network adapters – used both for host network access and Fiber Channel bus access – and a monolithic storage array in the guise of a CLARiiON CX4-240 complete with a complement of 20, 73GB STEC SSD’s – just to sweeten the pot.
VMmark Network Configuration for the UCS B200-M1
While it is clear from past VMmark posts that the network speed (beyond 1Gbps) has little to do with the results, it is nice to see the confidence Cisco has in the CNA approach (Cisco UCS M71KR-Q) to go with the “eggs in a basket” solution. Given the storage demands on the CNA, the VMmark result should remove any doubt about the viability (performance) of high-capacity tandems (we’ll leave the physical link security concerns for another day.)
However, where the “rubber meets the road” in this contest is storage I/O and this solution – in our opinion is just plain showing off. With just 41 disks to build from, the CX4-240 has been configured to deliver 37 LUNs – nearly one LUN per unit disk. Before any awards are given out for storage of the year, we need to consider that 36 of those LUNs are RAID0 – yielding a testing platform with no real-world analog (hence “showing off”.)
CLARiiON CX4-240 Storage Build-out for UCS B200-M1 VMmark
Given the ease at which RAID0 can be replaced by RAID1+0, it may be safe to assume that the same results could have been obtained by using 77 disks instead of 41 – at which point the CX4-240 would still be less than half the size of the top VMmark’s 172-disk solution. The reason is clear: SSD’s accelerate I/O loads incredibly well in architectures that support them. If anything, this “runner-up” proves that SSD adoption is on the verge of becoming mainstream.
But what does this test show about UCS? Firstly, it shows that Cisco’s platform can compete with the best solutions out there on CPU and I/O performance (what’s a half a percentage point across 102 virtual machines?) It’s not really a surprise given that the UCS platform was designed to do just that – and within a neatly managed framework. Secondly, it shows that the choice of EMC as a partner was an excellent one. As Martin Glassborow commented on his Storagebod’s Blog, EMC’s involvement in VMware has energized the storage vendor to take bold and innovative steps towards Cloud Computing solutions that it might not have done otherwise (like the RAID0 SSD array). Thirdly and most importantly, it underscores the importance of predictable performance in a virtualization solution. Given the UCS/vBlock approach to systems organization, it can be very difficult not to draw solid parallels between the benchmarks and expectations for net new builds based on the criterion.
Fujitsu’s RX300 S5 rack server takes the top spot in VMware’s VMmark for 8-core systems today with a score of 25.16@17 tiles. Loaded with two of Intel’s top-bin 3.33GHz, 130W Nehalem-EP processors (W5590, turbo to 3.6GHz per core) and 96GB of DDR3-1333 R-ECC memory, the RX300 bested the former champ – the HP ProLiant BL490c G6 blade – by only about 2.5%.
With 17 tiles and 102 virtual machines on a single 2U box, the RX300 S5 demonstrates precisely how well vSphere scales on today’s x86 commodity platforms. It also appears to demonstrate both the value and the limits of Intel’s “turbo mode” in its top-bin Nehalem-EP processors – especially in the virtualization use case – we’ll get to that later. In any case, the resulting equation is:
More * (Threads + Memory + I/O) = Dense Virtualization
We could have added “higher execution rates” to that equation, however, virtualization is a scale-out applications where threads, memory pool and I/O capabilities dominate the capacity equation – not clock speed. Adding 50% more clock provides less virtualization gains than adding 50% more cores, and reducing memory and context latency likewise provides better gains that simply upping the clock speed. That’s why a dual quad-core Nehalem 2.6GHz processor will crush a quad dual-core 3.5GHz (ill-fated) Tulsa.
Speaking of Tulsa, unlike Tulsa’s rather anaemic first-generation hyper-threading, Intel’s improved SMT in Nehalem “virtually” adds more core “power” to the Xeon by contributing up to 100% more thread capacity. This is demonstrated by Nehalem-EP’s 2 tiles per core contributions to VMmark where AMD’s Istanbul quad-core provides only 1 tile per core. But exactly what is a VMmark tile and how does core versus thread play into the result?
The Illustrated VMmark "Tile" Load
As you can see, a “VMmark Tile” – or just “tile” for short – is composed of 6 virtual machines, half running Windows, half running SUSE Linux. Likewise, half of the tiles are running in 64-bit mode while the other half runs in 32-bit mode. As a whole, the tile is composed of 10 virtual CPUs, 5GB of RAM and 62GB of storage. Looking at how the parts contribute to the whole, the tile is relatively balanced:
Operating System / Mode
Windows Server 2003 R2
SUSE Linux Enterprise Server 10 SP2
If we stop here and accept that today’s best x86 processors from AMD and Intel are capable of providing 1 tile for each thread, we can look at the thread count and calculate the number of tiles and resulting memory requirement. While that sounds like a good “rule of thumb” approach, it ignores specific use case scenarios where synthetic threads (like HT and SMT) do not scale linearly like core threads do where SMT accounts for only about 12% gains over single-threaded core, clock-for-clock. For this reason, processors from AMD and Intel in 2010 will feature more cores – 12 for AMD and 8 for Intel in their Magny-Cours and Nehalem-EX (aka “Beckton”), respectively.
Learning from the Master
If we want to gather some information about a specific field, we consult an expert, right? Judging from the results, Fujitsu’s latest dual-processor entry has definitely earned the title ‘Master of VMmark” in 2P systems – at least for now. So instead of the usual VMmark $/VM analysis (which are well established for recent VMmark entries), let’s look at the solution profile and try to glean some nuggets to take back to our data centers.
It’s Not About Raw Speed
First, we’ve noted that the processor used is not Intel’s standard “rack server” fare, but the more workstation oriented W-series Nehalem at 130W TDP. With “turbo mode” active, this CPU is capable of driving the 3.33GHz core – on a per-core basis – up to 3.6GHz. Since we’re seeing only a 2.5% improvement in overall score versus the ProLiant blade at 2.93GHz, we can extrapolate that the 2.93GHz X5570 Xeon is spending a lot of time at 3.33GHz – its “turbo” speed – while the power-hungry W5590 spends little time at 3.6GHz. How can we say this? Looking at the tile ratio as a function of the clock speed.
We know that the X5570 can run up to 3.33GHz, per core, according to thermal conditions on the chip. With proper cooling, this could mean up to 100% of the time (sorry, Google). Assuming for a moment that this is the case in the HP test environment (and there is sufficient cause to think so) then the ratio of the tile score to tile count and CPU frequency is 0.433 (24.54/17/3.33). If we examine the same ratio for the W5590, assuming the clock speed of 3.33GHz, we get 0.444 – a difference of 2.5%, or the contribution of “turbo” in the W5590. Likewise, if you back-figure the “apparent speed” of the X5570 using the ratio of the clock-locked W5590, you arrive at 3.25GHz for the W5570 (an 11% gain over base clock). In either case, it is clear that “turbo” is a better value at the low-end of the Nehalem spectrum as there isn’t enough thermal headroom for it to work well for the W-series.
VMmark Equals Meager Network Use
Second, we’re not seeing “fancy” networking tricks out of VMmark submissions. In the past, we’ve commented on the use of “consumer grade” switches in VMmark tests. For this reason, we can consider VMmark’s I/O dependency as related almost exclusively to storage. With respect to networking, the Fujitsu team simply interfaced three 1Gbps network adapter ports to the internal switch of the blade enclosure used to run the client-side load suite and ran with the test. Here’s what that looks like:
Networking Simplified: The "leaders" simple virtual networking topology.
Note that the network interfaces used for the VMmark trial are not from the on-board i82575EB network controller but from the PCI-Express quad-port adapter using its older cousin – the i82571EB. What is key here is that VMmark is tied to network performance issues, and it is more likely that additional network ports might increase the likelihood of IRQ sharing and reduced performance more so than the “optimization” of network flows.
Keeping Storage “Simple”
Third, Fujitsu’s approach to storage is elegantly simple: several “inexpensive” arrays with intelligent LUN allocation. For this, Fujistu employed eight of its ETERNUS DX80 Disk Storage Systems with 7 additional storage shelves for a total of 172 working disks and 23 LUNs. For simplicity, Fujistu used a pair of 8Gbps FC ports to feed ESX and at least one port per DX80 – all connected through a Brocade 5100 fabric switch. The result looked something like this:
And yes, the ESX server is configured to boot from SAN, using no locally attached storage. Note that the virtual machine configuration files, VM swap and ESX boot/swap are contained in a separate DX80 system. This “non-default” approach allows the working VMDKs of the virtual machines to be isolated – from a storage perspective – from the swap file overhead, about 5GB per tile. Again, this is a benchmark scenario, not an enterprise deployment, so trade-offs are in favour of performance, not CAPEX or OPEX.
Even if the DX80 solution falls into the $1K/TB range, to say that this approach to storage is “economic” requires a deeper look. At 33 rack units for the solution – including the FC switch but not including the blade chassis – this configuration has a hefty datacenter footprint. In contrast to the old-school server/blade approach, 1 rack at 3 servers per U is a huge savings over the 2 racks of blades or 3 racks of 1U rack servers. Had each of those servers of blades had a mirror pair, we’d be talking about 200+ disks spinning in those racks versus the 172 disks in the ETERNUS arrays, so that still represents a savings of 15.7% in storage-related power/space.
When will storage catch up?
Compared to a 98% reduction in network ports, a 30-80% reduction server/storage CAPEX (based on $1K/TB SAN), a 50-75% reduction in overall datacenter footprint, why is a 15% reduction in datacenter storage footprint acceptable? After all, storage – in the Fujitsu VMmark case – now represents 94% of the datacenter footprint. Even if the load were less aggressively spread across five ESX servers (a conservative 20:1 loading), the amount of space taken by storage only falls to 75%.
How can storage catch up to virtualization densities. First, with 2.5″ SAS drives, a bank of 172 disks can be made to occupy only 16U with very strong performance. This drops storage to only 60% of the datacenter footprint – 10U for hypervisor, 16U for storage, 26U total for this example. Moving from 3.5″ drives to 2.5″ drives takes care of the physical scaling issue with acceptable returns, but results in only minimal gains in terms of power savings.
Saving power in storage platforms is not going to be achieved by simply shrinking disk drives – shrinking the NUMBER of disks required per “effective” LUN is what’s necessary to overcome the power demands of modern, high-performance storage. This is where non-traditional technology like FLASH/SSD is being applied to improve performance while utilizing fewer disks and proportionately less power. For example, instead of dedicating disks on a per LUN basis, carving LUNs out of disk pools accelerated by FLASH (a hybrid storage pool) can result in a 30-40% reduction in disk count – when applied properly – and that means 30-40% reduction in datacenter space and power utilization.
Here are our “take aways” from the Fujitsu VMmark case:
1) Top-bin performance is at the losing end of diminishing returns. Unless your budget can accommodate this fact, purchasing decisions about virtualization compute platforms need to be aligned with $/VM within an acceptable performance envelope. When shopping CPU, make sure the top-bin’s “little brother” has the same architecture and feature set and go with the unit priced for the mainstream. (Don’t forget to factor memory density into the equation…) Regardless, try to stick within a $190-280/VM equipment budget for your hypervisor hardware and shoot for a 20-to-1 consolidation ratio (that’s at least $3,800-5,600 per server/blade).
2) While networking is not important to VMmark, this is likely not the case for most enterprise applications. Therefore, VMmark is not a good comparison case for your network-heavy applications. Also, adding more network ports increases capacity and redundancy but does so at the risk of IRQ-sharing (ESX, not ESXi) problems, not to mention the additional cost/number of network switching ports. This is where we think 10GE will significantly change the equation in 2010. Remember to add up the total number of in use ports – including out-of-band management – when factoring in switch density. For net new instalments, look for a switch that provides 10GE/SR or 10GE/CX4 options and go with !0GE/SR if power savings are driving your solution.
3) Storage should be simple, easy to manage, cheap (relatively speaking), dense and low-power. To meet these goals, look for storage technologies that utilize FLASH memory, tiered spindle types, smart block caching and other approaches to limit spindle count without sacrificing performance. Remember to factor in at least the cost of DAS when approximating your storage budget – about $150/VM in simple consolidation cases and $750/VM for more mission critical applications (that’s a range of $9,000-45,000 for a 3-server virtualization stack). The economies in managed storage come chiefly from the administration of the storage, but try to identify storage solutions that reduce datacenter footprint including both rack space and power consumption. Here’s where offerings from Sun and NexentaStor are showing real gains.
We’d like to see VMware update VMmark to include system power specifications so we can better gage – from the sidelines – what solution stack(s) perform according to our needs. VMmark served its purpose by giving the community a standard from which different platforms could be compared in terms of the resultant performance. With the world’s eyes on power consumption and the ecological impact of datacenter choices, adding a “power utilization component” to the “server-side” of the VMmark test would not be that significant of a “tweak.” Here’s how we think it can be done:
Require power consumption of the server/VMmark related components be recorded, including:
the ESX platform (rack server, blade & blade chassis, etc.)
the storage platform providing ESX and test LUN(s) (all heads, shelves, switches, etc.)
the switching fabric (i.e. Ethernet, 10GE, FC, etc.)
Power delivered to the test harness platforms, client load machines, etc. can be ignored;
Power measurements should be recorded at the following times:
All equipment off (validation check);
Single tile load;
100% tile capacity;
75% tile capacity;
50% tile capacity;
Power measurements should be recorded using a time-power data-logger with readings recorded as 5-minute averages;
Notations should be made concerning “cache warm-up” intervals, if applicable, where “cache optimized” storage is used.
Why is this important? In the wake of the VCE announcement, solution stacks like VCE need to be measured against each other in an easy to “consume” way. Is VCE the best platform versus a component solution provided by your local VMware integrator? Given that the differentiated VCE components are chiefly UCS, Cisco switching and EMC storage, it will be helpful to have a testing platform that can better differentiate “packaged solutions” instead of uncorrelated vendor “propaganda.”
Let us know what your thoughts are on the subject, either on Twitter or on our blog…
Virtual Storage Appliances (VSA) are really picking-up these days. Even the legacy hardware vendors are getting into the fray. They’re great in the lab and – assuming tailored performance – can fit some really interesting “embedded” applications.
If you haven’t had a chance to look at the EMC Celerra VSA then click over to Chad Sakac’s VirtualGeek Blog and have a look at his series on configuration and testing. If you have time, check out some of Chad’s more visionary stuff while your there – he has some good information on what’s to come in the next few months from EMC and VMware…
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