Click here to close now.


Open Source Cloud Authors: Liz McMillan, XebiaLabs Blog, Pat Romanski, Elizabeth White, Lori MacVittie

Blog Feed Post

Don’t Buy RAID cards for SSD Caching

“Where have you been Dog?”

The IT Dog here again, back from summer sabbatical. Well, it was more like an “election” sabbatical since I spent the last six months working on the campaign to elect Barkington T. Howl, III as President of United Dogs of America (UDA). “Bark,” as his frat brothers call him, turned out to be a little too high-brow and out of touch with the rank-and-file UDA constituency. He lost in a landslide. Anyway, I am now back at my day job, talking about SSDs in the IT marketplace. Did you miss me?

Back to Our Regularly Scheduled Blog Topic

So what is the first thing to write about since coming back? How about looking at a trend in the RAID marketplace – offering RAID controller cards sold with proprietary SSD caching software designed to boost performance over traditional RAID offerings.

SSD Caching RAID Controller Cards

Redundant Array of Independent Disks or RAIDs, as they are affectionately known, have been around for many years. They are a vital component in many IT installations offering data redundancy and performance improvements over standard disk array. With the introduction of SSDs and SSD caching, many RAID controller card manufactures have updated their product offering to include the ability to run SSD caching algorithms on the RAID controller card itself. Examples of this in the market place include LSI MegaRAID controller card with CacheCade SSD caching software and Adaptec Series 7 controller cards with maxCache SSD caching software. The basic idea here is to buy the controller card from a particular vendor and use the SSD caching software they offer that runs only on their controller card.

Show Me The Money

Ok, so I understand the idea. Let’s see if we can figure out if this is the right way to do SSD caching. I am going to talk about LSI’s solution, not because “LSI” is easier to type than “Adaptec”, but because there happen to be some independent test results published on the web by Demartek for LSI MegaRAID with CacheCade. I am going to try and decipher just what the results are telling me. You can click on the link to read the entire report which documents test set-up etc. I am just going to discuss one chart presented to see what the fuss is about.

Figure 1 below is from page 8 of the report. It shows throughput in Megabits per second for a 90 minute web server test for the baseline system with no SSD caching and for the same system with SSD caching using one or two Intel X25-E 32GB SLC SSDs. The chart shows the baseline system without SSD caching maxed out at about 58 Mbps and that using one SSD and SSD caching, the performance improved to approximately 211 Mbps. Pretty nice. 3.6X improvement. And, with 2 SSDs for caching the throughput improved to 416 Mbps. 7.1X improvement! Excellent.

But let me dig into this a little more. The first thing I am trying to understand is just how they could get only 58 Mbps out of the baseline system. Remember now this is MegaBITS per second, not MegaBYTES per second. I am not a RAID controller guru, but I would have expected the baseline performance to be greater than 7.25 Mbytes/s. A quick internet search of RAID performance led me to this ZDNet page which listed a test RAID performance in MegaBYTES/s ranging from 64 to 257. So the baseline figure for the LSI test is suspect and therefore 3.6X or 7.1X improvement of really bad performance is not that impressive. But, if we ignore ___X improvement and just look at the data – 211 Mbits/sec (that’s 26 Mbytes/sec to you and me) is nothing to be too excited about.

Figure 1. LSI MegaRAID with CaceCade Demartek Throughput. Source:

Velobit SSD Caching Software Results

So, I was trying to come up with an apples-to-apples comparison for the RAID SSD caching test data shown above but unfortunately I don’t have data which exactly duplicates the LSI test. However, Demartek performed system testing using Velobit HyperCache SSD caching software under different conditions which can be used to provide some general comparison observations.

Figure 2. below is taken from page 12 the Velobit Demartek report. The chart title is confusing: “Average MBPS – Linux without RD2”. When translated to English, the title means: Average MegaBYTES/s of a Linux based system running the vdbench workload test. The ‘without RD2’ part of the title means that there is a second chart in the report with a test called ‘RD2’ (mostly read operations test) whose results (more than 3200 Mbytes/s) cause the other test results shown in the first graph on P12 to be compressed and difficult to read. So the RD2 test results are removed for this graph (see the report) to zoom in on RD1, RD3 and RD4 results. Well, that was a lot to explain for a chart title, sorry about that.

Anyway, several takeaways (don’t you just hate that word) from this data:
1. The baseline performance for each test ranged from approx. 20-35 Mbytes/s (Mbytes!). Much higher than the baseline for the LSI tests (7.25 Mbytes/s).
2. The Velobit Hypercache performance ranged from 200 to 275 Mbytes/s (that is 1600 - 2200 Mbits/s to keep the same units as the LSI results)
3. These tests results also show testing results of FlashSoft SSD caching software because FlashSoft was available at Demartek for comparison purposes. By the way, FlashSoft outperforms the LSI CacheCade software significantly also.

Figure 2. Velobit HyperCache SSD Caching Software Demartek Test Results. Source:


This was a long and winding road to try to make a simple point. RAID systems and SSD caching are two independent components within your IT system. If you have to go with a RAID solution for redundancy reasons, don’t get lured into the illusion that you can solve two problems with one product: you do need to have your RAID solution also be your SSD caching solution. It may seem easy to combine RAID and SSD caching for you, but if you try to solve two independent ‘problems’ with one product, you may not be getting the best performance for either problem. SSD caching enabled RAID controller cards:

  • tend to be more expensive than standard RAID controller cards
  • limit your SSD caching software solutions to software compatible with that card (vendor lock-in)
  • do not perform as well as other SSD caching options

The benefit of using RAID based SSD caching is the software runs on the RAID card and does not consume any server CPU/memory resources. However, the benefits don’t seem to be worth the cost and performance hit you take by using this solution.

Read the original blog entry...

More Stories By Peter Velikin

Peter Velikin has 12 years of experience creating new markets and commercializing products in multiple high tech industries. Prior to VeloBit, he was VP Marketing at Zmags, a SaaS-based digital content platform for e-commerce and mobile devices, where he managed all aspects of marketing, product management, and business development. Prior to that, Peter was Director of Product and Market Strategy at PTC, responsible for PTC’s publishing, content management, and services solutions. Prior to PTC, Peter was at EMC Corporation, where he held roles in product management, business development, and engineering program management.

Peter has an MS in Electrical Engineering from Boston University and an MBA from Harvard Business School.

@ThingsExpo Stories
In his session at @ThingsExpo, Tony Shan, Chief Architect at CTS, will explore the synergy of Big Data and IoT. First he will take a closer look at the Internet of Things and Big Data individually, in terms of what, which, why, where, when, who, how and how much. Then he will explore the relationship between IoT and Big Data. Specifically, he will drill down to how the 4Vs aspects intersect with IoT: Volume, Variety, Velocity and Value. In turn, Tony will analyze how the key components of IoT influence Big Data: Device, Connectivity, Context, and Intelligence. He will dive deep to the matrix...
When it comes to IoT in the enterprise, namely the commercial building and hospitality markets, a benefit not getting the attention it deserves is energy efficiency, and IoT’s direct impact on a cleaner, greener environment when installed in smart buildings. Until now clean technology was offered piecemeal and led with point solutions that require significant systems integration to orchestrate and deploy. There didn't exist a 'top down' approach that can manage and monitor the way a Smart Building actually breathes - immediately flagging overheating in a closet or over cooling in unoccupied ho...
Scott Guthrie's keynote presentation "Journey to the intelligent cloud" is a must view video. This is from AzureCon 2015, September 29, 2015 I have reproduced some screen shots in case you are unable to view this long video for one reason or another. One of the highlights is 3 datacenters coming on line in India.
“The Internet of Things transforms the way organizations leverage machine data and gain insights from it,” noted Splunk’s CTO Snehal Antani, as Splunk announced accelerated momentum in Industrial Data and the IoT. The trend is driven by Splunk’s continued investment in its products and partner ecosystem as well as the creativity of customers and the flexibility to deploy Splunk IoT solutions as software, cloud services or in a hybrid environment. Customers are using Splunk® solutions to collect and correlate data from control systems, sensors, mobile devices and IT systems for a variety of Ind...
SYS-CON Events announced today that ProfitBricks, the provider of painless cloud infrastructure, will exhibit at SYS-CON's 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. ProfitBricks is the IaaS provider that offers a painless cloud experience for all IT users, with no learning curve. ProfitBricks boasts flexible cloud servers and networking, an integrated Data Center Designer tool for visual control over the cloud and the best price/performance value available. ProfitBricks was named one of the coolest Clo...
You have your devices and your data, but what about the rest of your Internet of Things story? Two popular classes of technologies that nicely handle the Big Data analytics for Internet of Things are Apache Hadoop and NoSQL. Hadoop is designed for parallelizing analytical work across many servers and is ideal for the massive data volumes you create with IoT devices. NoSQL databases such as Apache HBase are ideal for storing and retrieving IoT data as “time series data.”
Clearly the way forward is to move to cloud be it bare metal, VMs or containers. One aspect of the current public clouds that is slowing this cloud migration is cloud lock-in. Every cloud vendor is trying to make it very difficult to move out once a customer has chosen their cloud. In his session at 17th Cloud Expo, Naveen Nimmu, CEO of Clouber, Inc., will advocate that making the inter-cloud migration as simple as changing airlines would help the entire industry to quickly adopt the cloud without worrying about any lock-in fears. In fact by having standard APIs for IaaS would help PaaS expl...
Organizations already struggle with the simple collection of data resulting from the proliferation of IoT, lacking the right infrastructure to manage it. They can't only rely on the cloud to collect and utilize this data because many applications still require dedicated infrastructure for security, redundancy, performance, etc. In his session at 17th Cloud Expo, Emil Sayegh, CEO of Codero Hosting, will discuss how in order to resolve the inherent issues, companies need to combine dedicated and cloud solutions through hybrid hosting – a sustainable solution for the data required to manage I...
Apps and devices shouldn't stop working when there's limited or no network connectivity. Learn how to bring data stored in a cloud database to the edge of the network (and back again) whenever an Internet connection is available. In his session at 17th Cloud Expo, Bradley Holt, Developer Advocate at IBM Cloud Data Services, will demonstrate techniques for replicating cloud databases with devices in order to build offline-first mobile or Internet of Things (IoT) apps that can provide a better, faster user experience, both offline and online. The focus of this talk will be on IBM Cloudant, Apa...
Mobile messaging has been a popular communication channel for more than 20 years. Finnish engineer Matti Makkonen invented the idea for SMS (Short Message Service) in 1984, making his vision a reality on December 3, 1992 by sending the first message ("Happy Christmas") from a PC to a cell phone. Since then, the technology has evolved immensely, from both a technology standpoint, and in our everyday uses for it. Originally used for person-to-person (P2P) communication, i.e., Sally sends a text message to Betty – mobile messaging now offers tremendous value to businesses for customer and empl...
As more and more data is generated from a variety of connected devices, the need to get insights from this data and predict future behavior and trends is increasingly essential for businesses. Real-time stream processing is needed in a variety of different industries such as Manufacturing, Oil and Gas, Automobile, Finance, Online Retail, Smart Grids, and Healthcare. Azure Stream Analytics is a fully managed distributed stream computation service that provides low latency, scalable processing of streaming data in the cloud with an enterprise grade SLA. It features built-in integration with Azur...
SYS-CON Events announced today that HPM Networks will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. For 20 years, HPM Networks has been integrating technology solutions that solve complex business challenges. HPM Networks has designed solutions for both SMB and enterprise customers throughout the San Francisco Bay Area.
The enterprise is being consumerized, and the consumer is being enterprised. Moore's Law does not matter anymore, the future belongs to business virtualization powered by invisible service architecture, powered by hyperscale and hyperconvergence, and facilitated by vertical streaming and horizontal scaling and consolidation. Both buyers and sellers want instant results, and from paperwork to paperless to mindless is the ultimate goal for any seamless transaction. The sweetest sweet spot in innovation is automation. The most painful pain point for any business is the mismatch between supplies a...
The broad selection of hardware, the rapid evolution of operating systems and the time-to-market for mobile apps has been so rapid that new challenges for developers and engineers arise every day. Security, testing, hosting, and other metrics have to be considered through the process. In his session at Big Data Expo, Walter Maguire, Chief Field Technologist, HP Big Data Group, at Hewlett-Packard, will discuss the challenges faced by developers and a composite Big Data applications builder, focusing on how to help solve the problems that developers are continuously battling.
SYS-CON Events announced today that IBM Cloud Data Services has been named “Bronze Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. IBM Cloud Data Services offers a portfolio of integrated, best-of-breed cloud data services for developers focused on mobile computing and analytics use cases.
As enterprises capture more and more data of all types – structured, semi-structured, and unstructured – data discovery requirements for business intelligence (BI), Big Data, and predictive analytics initiatives grow more complex. A company’s ability to become data-driven and compete on analytics depends on the speed with which it can provision their analytics applications with all relevant information. The task of finding data has traditionally resided with IT, but now organizations increasingly turn towards data source discovery tools to find the right data, in context, for business users, d...
SYS-CON Events announced today that MobiDev, a software development company, will exhibit at the 17th International Cloud Expo®, which will take place November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. MobiDev is a software development company with representative offices in Atlanta (US), Sheffield (UK) and Würzburg (Germany); and development centers in Ukraine. Since 2009 it has grown from a small group of passionate engineers and business managers to a full-scale mobile software company with over 150 developers, designers, quality assurance engineers, project manage...
Learn how IoT, cloud, social networks and last but not least, humans, can be integrated into a seamless integration of cooperative organisms both cybernetic and biological. This has been enabled by recent advances in IoT device capabilities, messaging frameworks, presence and collaboration services, where devices can share information and make independent and human assisted decisions based upon social status from other entities. In his session at @ThingsExpo, Michael Heydt, founder of Seamless Thingies, will discuss and demonstrate how devices and humans can be integrated from a simple clust...
SYS-CON Events announced today that Cloud Raxak has been named “Media & Session Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Raxak Protect automates security compliance across private and public clouds. Using the SaaS tool or managed service, developers can deploy cloud apps quickly, cost-effectively, and without error.
Who are you? How do you introduce yourself? Do you use a name, or do you greet a friend by the last four digits of his social security number? Assuming you don’t, why are we content to associate our identity with 10 random digits assigned by our phone company? Identity is an issue that affects everyone, but as individuals we don’t spend a lot of time thinking about it. In his session at @ThingsExpo, Ben Klang, Founder & President of Mojo Lingo, will discuss the impact of technology on identity. Should we federate, or not? How should identity be secured? Who owns the identity? How is identity ...