Welcome!

Apache Authors: Gil Allouche, Liz McMillan, William Schmarzo, Christopher Harrold, Elizabeth White

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
With 15% of enterprises adopting a hybrid IT strategy, you need to set a plan to integrate hybrid cloud throughout your infrastructure. In his session at 18th Cloud Expo, Steven Dreher, Director of Solutions Architecture at Green House Data, discussed how to plan for shifting resource requirements, overcome challenges, and implement hybrid IT alongside your existing data center assets. Highlights included anticipating workload, cost and resource calculations, integrating services on both sides...
Manufacturers are embracing the Industrial Internet the same way consumers are leveraging Fitbits – to improve overall health and wellness. Both can provide consistent measurement, visibility, and suggest performance improvements customized to help reach goals. Fitbit users can view real-time data and make adjustments to increase their activity. In his session at @ThingsExpo, Mark Bernardo Professional Services Leader, Americas, at GE Digital, discussed how leveraging the Industrial Internet a...
Big Data engines are powering a lot of service businesses right now. Data is collected from users from wearable technologies, web behaviors, purchase behavior as well as several arbitrary data points we’d never think of. The demand for faster and bigger engines to crunch and serve up the data to services is growing exponentially. You see a LOT of correlation between “Cloud” and “Big Data” but on Big Data and “Hybrid,” where hybrid hosting is the sanest approach to the Big Data Infrastructure pro...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
A critical component of any IoT project is what to do with all the data being generated. This data needs to be captured, processed, structured, and stored in a way to facilitate different kinds of queries. Traditional data warehouse and analytical systems are mature technologies that can be used to handle certain kinds of queries, but they are not always well suited to many problems, particularly when there is a need for real-time insights.
The best-practices for building IoT applications with Go Code that attendees can use to build their own IoT applications. In his session at @ThingsExpo, Indraneel Mitra, Senior Solutions Architect & Technology Evangelist at Cognizant, provided valuable information and resources for both novice and experienced developers on how to get started with IoT and Golang in a day. He also provided information on how to use Intel Arduino Kit, Go Robotics API and AWS IoT stack to build an application tha...
IoT generates lots of temporal data. But how do you unlock its value? You need to discover patterns that are repeatable in vast quantities of data, understand their meaning, and implement scalable monitoring across multiple data streams in order to monetize the discoveries and insights. Motif discovery and deep learning platforms are emerging to visualize sensor data, to search for patterns and to build application that can monitor real time streams efficiently. In his session at @ThingsExpo, ...
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
Extracting business value from Internet of Things (IoT) data doesn’t happen overnight. There are several requirements that must be satisfied, including IoT device enablement, data analysis, real-time detection of complex events and automated orchestration of actions. Unfortunately, too many companies fall short in achieving their business goals by implementing incomplete solutions or not focusing on tangible use cases. In his general session at @ThingsExpo, Dave McCarthy, Director of Products...
Amazon has gradually rolled out parts of its IoT offerings in the last year, but these are just the tip of the iceberg. In addition to optimizing their back-end AWS offerings, Amazon is laying the ground work to be a major force in IoT – especially in the connected home and office. Amazon is extending its reach by building on its dominant Cloud IoT platform, its Dash Button strategy, recently announced Replenishment Services, the Echo/Alexa voice recognition control platform, the 6-7 strategic...
WebRTC is bringing significant change to the communications landscape that will bridge the worlds of web and telephony, making the Internet the new standard for communications. Cloud9 took the road less traveled and used WebRTC to create a downloadable enterprise-grade communications platform that is changing the communication dynamic in the financial sector. In his session at @ThingsExpo, Leo Papadopoulos, CTO of Cloud9, discussed the importance of WebRTC and how it enables companies to focus...
Verizon Communications Inc. (NYSE, Nasdaq: VZ) and Yahoo! Inc. (Nasdaq: YHOO) have entered into a definitive agreement under which Verizon will acquire Yahoo's operating business for approximately $4.83 billion in cash, subject to customary closing adjustments. Yahoo informs, connects and entertains a global audience of more than 1 billion monthly active users** -- including 600 million monthly active mobile users*** through its search, communications and digital content products. Yahoo also co...
"There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
SYS-CON Events announced today that LeaseWeb USA, a cloud Infrastructure-as-a-Service (IaaS) provider, will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. LeaseWeb is one of the world's largest hosting brands. The company helps customers define, develop and deploy IT infrastructure tailored to their exact business needs, by combining various kinds cloud solutions.
Is your aging software platform suffering from technical debt while the market changes and demands new solutions at a faster clip? It’s a bold move, but you might consider walking away from your core platform and starting fresh. ReadyTalk did exactly that. In his General Session at 19th Cloud Expo, Michael Chambliss, Head of Engineering at ReadyTalk, will discuss why and how ReadyTalk diverted from healthy revenue and over a decade of audio conferencing product development to start an innovati...
It’s 2016: buildings are smart, connected and the IoT is fundamentally altering how control and operating systems work and speak to each other. Platforms across the enterprise are networked via inexpensive sensors to collect massive amounts of data for analytics, information management, and insights that can be used to continuously improve operations. In his session at @ThingsExpo, Brian Chemel, Co-Founder and CTO of Digital Lumens, will explore: The benefits sensor-networked systems bring to ...
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
There will be new vendors providing applications, middleware, and connected devices to support the thriving IoT ecosystem. This essentially means that electronic device manufacturers will also be in the software business. Many will be new to building embedded software or robust software. This creates an increased importance on software quality, particularly within the Industrial Internet of Things where business-critical applications are becoming dependent on products controlled by software. Qua...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2016 Silicon Valley. The 19th Cloud Expo and 6th @ThingsExpo will take place on November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Interne...