Click here to close now.

Welcome!

Apache Authors: Nikita Ivanov, VictorOps Blog, Carmen Gonzalez, Sematext Blog, Ruxit Blog

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: http://www.demartek.com/Reports_Free/Demartek_LSI_CacheCade_Performance_...

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: http://www.velobit.com/Portals/106427/docs/demartek_velobit_ssd_caching_...

Conclusion

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
One of the biggest impacts of the Internet of Things is and will continue to be on data; specifically data volume, management and usage. Companies are scrambling to adapt to this new and unpredictable data reality with legacy infrastructure that cannot handle the speed and volume of data. In his session at @ThingsExpo, Don DeLoach, CEO and president of Infobright, will discuss how companies need to rethink their data infrastructure to participate in the IoT, including: Data storage: Understanding the kinds of data: structured, unstructured, big/small? Analytics: What kinds and how responsiv...
Cloudian, Inc., the leading provider of hybrid cloud storage solutions, today announced availability of Cloudian HyperStore 5.1 software. HyperStore 5.1 is an enhanced Amazon S3-compliant, plug-and-play hybrid cloud software solution that now features full Apache Hadoop integration. Enterprises can now transform big data into smart data by running Hadoop analytics on HyperStore software and appliances. This in-place analytics, with no need to offload data to other systems for Hadoop analyses, enables customers to derive meaningful business intelligence from their data quickly, efficiently and ...
Since 2008 and for the first time in history, more than half of humans live in urban areas, urging cities to become “smart.” Today, cities can leverage the wide availability of smartphones combined with new technologies such as Beacons or NFC to connect their urban furniture and environment to create citizen-first services that improve transportation, way-finding and information delivery. In her session at @ThingsExpo, Laetitia Gazel-Anthoine, CEO of Connecthings, will focus on successful use cases.
Sensor-enabled things are becoming more commonplace, precursors to a larger and more complex framework that most consider the ultimate promise of the IoT: things connecting, interacting, sharing, storing, and over time perhaps learning and predicting based on habits, behaviors, location, preferences, purchases and more. In his session at @ThingsExpo, Tom Wesselman, Director of Communications Ecosystem Architecture at Plantronics, will examine the still nascent IoT as it is coalescing, including what it is today, what it might ultimately be, the role of wearable tech, and technology gaps stil...
The true value of the Internet of Things (IoT) lies not just in the data, but through the services that protect the data, perform the analysis and present findings in a usable way. With many IoT elements rooted in traditional IT components, Big Data and IoT isn’t just a play for enterprise. In fact, the IoT presents SMBs with the prospect of launching entirely new activities and exploring innovative areas. CompTIA research identifies several areas where IoT is expected to have the greatest impact.
Wearable devices have come of age. The primary applications of wearables so far have been "the Quantified Self" or the tracking of one's fitness and health status. We propose the evolution of wearables into social and emotional communication devices. Our BE(tm) sensor uses light to visualize the skin conductance response. Our sensors are very inexpensive and can be massively distributed to audiences or groups of any size, in order to gauge reactions to performances, video, or any kind of presentation. In her session at @ThingsExpo, Jocelyn Scheirer, CEO & Founder of Bionolux, will discuss ho...
The explosion of connected devices / sensors is creating an ever-expanding set of new and valuable data. In parallel the emerging capability of Big Data technologies to store, access, analyze, and react to this data is producing changes in business models under the umbrella of the Internet of Things (IoT). In particular within the Insurance industry, IoT appears positioned to enable deep changes by altering relationships between insurers, distributors, and the insured. In his session at @ThingsExpo, Michael Sick, a Senior Manager and Big Data Architect within Ernst and Young's Financial Servi...
The Internet of Everything (IoE) brings together people, process, data and things to make networked connections more relevant and valuable than ever before – transforming information into knowledge and knowledge into wisdom. IoE creates new capabilities, richer experiences, and unprecedented opportunities to improve business and government operations, decision making and mission support capabilities. In his session at @ThingsExpo, Gary Hall, Chief Technology Officer, Federal Defense at Cisco Systems, will break down the core capabilities of IoT in multiple settings and expand upon IoE for bo...
SYS-CON Events announced today that Vitria Technology, Inc. will exhibit at SYS-CON’s @ThingsExpo, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. Vitria will showcase the company’s new IoT Analytics Platform through live demonstrations at booth #330. Vitria’s IoT Analytics Platform, fully integrated and powered by an operational intelligence engine, enables customers to rapidly build and operationalize advanced analytics to deliver timely business outcomes for use cases across the industrial, enterprise, and consumer segments.
The Internet of Things (IoT) is causing data centers to become radically decentralized and atomized within a new paradigm known as “fog computing.” To support IoT applications, such as connected cars and smart grids, data centers' core functions will be decentralized out to the network's edges and endpoints (aka “fogs”). As this trend takes hold, Big Data analytics platforms will focus on high-volume log analysis (aka “logs”) and rely heavily on cognitive-computing algorithms (aka “cogs”) to make sense of it all.
SYS-CON Events announced today that GENBAND, a leading developer of real time communications software solutions, has been named “Silver Sponsor” of SYS-CON's WebRTC Summit, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. The GENBAND team will be on hand to demonstrate their newest product, Kandy. Kandy is a communications Platform-as-a-Service (PaaS) that enables companies to seamlessly integrate more human communications into their Web and mobile applications - creating more engaging experiences for their customers and boosting collaboration and productiv...
From telemedicine to smart cars, digital homes and industrial monitoring, the explosive growth of IoT has created exciting new business opportunities for real time calls and messaging. In his session at @ThingsExpo, Ivelin Ivanov, CEO and Co-Founder of Telestax, shared some of the new revenue sources that IoT created for Restcomm – the open source telephony platform from Telestax. Ivelin Ivanov is a technology entrepreneur who founded Mobicents, an Open Source VoIP Platform, to help create, deploy, and manage applications integrating voice, video and data. He is the co-founder of TeleStax, a...
The industrial software market has treated data with the mentality of “collect everything now, worry about how to use it later.” We now find ourselves buried in data, with the pervasive connectivity of the (Industrial) Internet of Things only piling on more numbers. There’s too much data and not enough information. In his session at @ThingsExpo, Bob Gates, Global Marketing Director, GE’s Intelligent Platforms business, to discuss how realizing the power of IoT, software developers are now focused on understanding how industrial data can create intelligence for industrial operations. Imagine ...
The explosion of connected devices / sensors is creating an ever-expanding set of new and valuable data. In parallel the emerging capability of Big Data technologies to store, access, analyze, and react to this data is producing changes in business models under the umbrella of the Internet of Things (IoT). In particular within the Insurance industry, IoT appears positioned to enable deep changes by altering relationships between insurers, distributors, and the insured. In his session at @ThingsExpo, Michael Sick, a Senior Manager and Big Data Architect within Ernst and Young's Financial Servi...
The 3rd International @ThingsExpo, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - is now accepting submissions to demo smart cars on the Expo Floor. Smart car sponsorship benefits include general brand exposure and increasing engagement with the developer ecosystem.
Operational Hadoop and the Lambda Architecture for Streaming Data Apache Hadoop is emerging as a distributed platform for handling large and fast incoming streams of data. Predictive maintenance, supply chain optimization, and Internet-of-Things analysis are examples where Hadoop provides the scalable storage, processing, and analytics platform to gain meaningful insights from granular data that is typically only valuable from a large-scale, aggregate view. One architecture useful for capturing and analyzing streaming data is the Lambda Architecture, representing a model of how to analyze rea...
Sensor-enabled things are becoming more commonplace, precursors to a larger and more complex framework that most consider the ultimate promise of the IoT: things connecting, interacting, sharing, storing, and over time perhaps learning and predicting based on habits, behaviors, location, preferences, purchases and more. In his session at @ThingsExpo, Tom Wesselman, Director of Communications Ecosystem Architecture at Plantronics, will examine the still nascent IoT as it is coalescing, including what it is today, what it might ultimately be, the role of wearable tech, and technology gaps stil...
SYS-CON Events announced today that Open Data Centers (ODC), a carrier-neutral colocation provider, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. Open Data Centers is a carrier-neutral data center operator in New Jersey and New York City offering alternative connectivity options for carriers, service providers and enterprise customers.
When it comes to the Internet of Things, hooking up will get you only so far. If you want customers to commit, you need to go beyond simply connecting products. You need to use the devices themselves to transform how you engage with every customer and how you manage the entire product lifecycle. In his session at @ThingsExpo, Sean Lorenz, Technical Product Manager for Xively at LogMeIn, will show how “product relationship management” can help you leverage your connected devices and the data they generate about customer usage and product performance to deliver extremely compelling and reliabl...
SYS-CON Events announced today that SoftLayer, an IBM company, has been named “Gold Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place June 9-11, 2015 at the Javits Center in New York City, NY, and the 17th International Cloud Expo®, which will take place November 3–5, 2015 at the Santa Clara Convention Center in Santa Clara, CA. SoftLayer operates a global cloud infrastructure platform built for Internet scale. With a global footprint of data centers and network points of presence, SoftLayer provides infrastructure as a service to leading-edge customers ranging from ...