DDN’s storage systems leverage a clustered architecture of 4U chassis, each with as many as 84 disk drives (HDD and SSD), processing power and up to 16 InfiniBand ports. In an active/active configuration, the Storage Fusion Architecture (SFA) 12K can produce an amazing 40 gigabytes per second (GBps) of throughput and 1.4 million sustained IOPS (1 terabyte per second with 25 modules). DDN systems also have some of the best density available, with more than 7.6 petabytes (PB) stored in two data center floor tiles.

The products’ performance comes from a silicon-based data architecture with intelligent write caching and a non-blocking internal SAS fabric. Unlike the commodity hardware that’s become so popular in storage lately, DDN’s SFA can actually support SSDs at their rated speed, along with spinning disk drives in the same chassis. This eliminates the need for special hybrid storage appliances with embedded flash or PCIe-based flash devices.

DDN combines these modules into scalable NAS systems, parallel storage appliances and streaming content delivery systems. It has also been early to the game with object storage technologies. The Web Object Scaler (WOS) is a scale-out object-based storage system that debuted about three years ago. It replaces the central metadata store that maintains the hierarchical structure of a traditional file system with a flat index of object identifiers. This allows nearly unlimited capacity growth, while maintaining performance and, combined with erasure coding technologies, enables the geographic dispersion of data as well.

According to DDN, its technology is behind eight of the top 10 HPC systems in the world. And WOS is being used as the back-end infrastructure for multiple high-profile cloud companies. In keeping with its expansion plans, DDN is looking for qualified VARs and MSPs to take its technology up against the big legacy storage companies. For VARs looking for a disruptive solution, this would certainly qualify.

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But he said his company would start looking for new solutions when customers had clearly unmet needs that it couldn’t satisfy with its existing products. Said another way, it was time to find a new vendor when defending the technology of its current vendors’ products no longer made sense. All vendors’ product lines cover a range of use cases or certain segments of the overall market. They also have “sweet spot” use cases that they handle really well, and the opposite, which I like to call “flat spots” (think of the bottom of a melon). These are the use cases their technology doesn’t cover well.

All VARs (and most customers) are aware that most vendors will exaggerate their range to some extent and tend to ignore their flat spots, which can become more pronounced as a technology gets older. One of the primary value propositions that customers rely on VARs to provide is knowing these flat spots and having the independence to say so, and then to recommend an alternative when it’s appropriate.

From the VAR’s perspective, promoting products that aren’t as strong a fit for an application is a good way to lose a deal because they can be fairly certain that another VAR will bring in a better solution. This is the scenario mentioned above that prompts VARs to look for a new vendor.

One example could be selling a “name brand” disk array system when there’s a lesser-known solution that has comparable specs and a much lower price tag. Years ago, NAS appliances were sold primarily by one or two leading vendors. Now there are many alternatives to these Tier 1 brands — both hardware appliances and software-based SAN file systems — that could be very appealing to customers looking to save some money.

Another example is solid-state storage devices. SSDs have become an accepted solution in environments where more application performance is needed, and an appealing alternative to high-spindle-count configurations that legacy disk array vendors have traditionally sold. Now these companies are offering SSDs but most often as hard drive replacements in their existing arrays. Server-side caching and tiering is a viable technology but one that’s not available from most Tier 1 disk array vendors. And then there’s network-based flash caching appliances and all-flash storage arrays. While definitely more specialized solutions, these products can offer astounding performance at competitive price points, in the right application scenario.

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NAS cache

For file storage environments that need better performance than is available from existing NAS systems, a network-based caching appliance like CacheIQ can be an appealing solution. These appliances sit in-line, between existing NAS systems and application servers, caching frequently accessed files. Most contain a combination of SSD and DRAM memory and provide a nondisruptive implementation of solid-state performance in an existing storage environment. Also, since they can support multiple NAS devices, the cost of the SSD purchase can be spread out across more storage systems.

SAN cache

For high-performance block storage environments, like online databases and SAN-attached virtualization implementations, block-based caching appliances like those from GridIron Systems are also available. These solutions contain DRAM and SSD flash capacity and connect to a Fibre Channel SAN, servicing multiple storage arrays. Block-based caching solutions install on the network and start improving performance, transparently. For databases, this means no changes to application code and no ongoing administration tasks.

Network-based caching appliances are designed for the performance characteristics of solid-state storage and aren’t limited by a legacy architecture that was built for HDDs. They can provide a transparent performance boost to existing SAN or NAS environments that doesn’t require the management of an SSD tier. Since they can front-end storage systems from different manufacturers, they allow SSD costs to be spread across multiple storage systems and give customers a way to keep using existing disk arrays.

For VARs, network-based caching appliances can be an excellent option for an account that needs more performance for critical applications but is tired of paying “minibar prices” for storage upgrades to their existing Tier 1 arrays, upgrades that may not meet their expectations anyway. These solutions can boost performance without complex storage tiering and enable users to keep running existing storage systems.

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Server-side caching or tiering systems essentially augment hard disk drive (HDD) performance; they don’t replace disk drive arrays. This means they need to run a process to analyze and determine which data sets should be on flash and then move those data at the appropriate time. The net effect of these processes can be increased system complexity and reduced overall performance.

For tiering systems, this analysis is typically applied only after data’s been written to the HDD tier and can involve a “warming” period where multiple accesses are analyzed. Moving those data at the appropriate time also creates storage controller overhead, especially on the hard disk array that it’s supporting.

But there’s another issue: flash endurance. As we covered in the first blog post of this series, “Server-side flash implementation explainer,” flash memory can support a finite number of write and erase cycles. The data turnover of caching or tiering consumes more of these cycles, shortening the effective useful life of flash devices.

All-flash arrays are an alternative to caching and tiering systems that can address these issues.

All-flash arrays are complete storage systems with storage controllers, modular flash capacity and storage services (RAID, snapshots, cloning, replication, etc.). They also can support multiple storage protocols — either block storage or both block and file storage. They use storage controllers that are designed for flash’s performance, breaking free from the limitations of putting flash in legacy disk arrays that used HDD controllers designed around the latency of spinning disk drives.

These modular systems implement like traditional disk arrays, providing data centers with flash performance without the complexity and potential side effects of caching or tiering. They also leverage flash’s performance to bring acquisition costs closer to that of the high-performance HDD arrays they’re replacing.

All-flash arrays also include data reduction technologies like thin provisioning, deduplication and compression to decrease the amount of capacity they need to store a given data set. Unlike HDD arrays, flash-only systems have plenty of performance to accommodate the CPU load of these processes. This can bring typical data reduction rates up to 10 times or more, driving down their effective cost per gigabyte. When compared with the disk drive arrays they’re replacing, typically high-performance SAS or Fibre Channel systems in high-spindle-count configurations, flash-only arrays can be more than cost-competitive.

Nimbus Data Systems was one of the first on the market with an all-flash array but has been joined more recently by others, like Pure Storage. All-flash systems are not for every environment but are certainly a product that should get serious line-card consideration for VARs interested in embracing flash as part of their storage go-to-market strategies. As a disruptive alternative to legacy high-performance storage arrays, they can be an ideal way to get into a new account or unseat an incumbent vendor.

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Flash is getting more affordable but is still several times the cost per gigabyte of hard disk drives (HDDs). Because of the cost disparity, it’s often used to augment HDD performance: The more performance-critical data sets are placed on flash, sometimes temporarily, to take advantage of its orders-of-magnitude better performance, especially IOPS.

Read caching involves placing a copy of the most frequently used data objects into SSD to speed access times by applications or users. When data’s changing, it’s more complicated (write caching) since the primary data set must be kept updated and writes must be protected against system failures until they’re committed to nonvolatile storage. But there are algorithms that can do this too, as part of the OS or application or as a part of a PCIe card that houses the flash storage itself.

Caching can be the simplest to implement, since it leaves the primary copy of data intact on existing disk storage, often operating transparently to the application. It can also be implemented with a relatively small amount of SSD capacity, since data can be moved into and out of the cache area rapidly.

Tiering is like caching except it involves moving an entire application or data set into cache and then copying back to primary storage when the period of high activity is over. For this reason, tiering typically requires more SSD capacity than caching and may involve configuration changes to the application.

Server-side flash implementations can be done with PCIe flash devices, which can have up to a terabyte or more of flash capacity and may include caching software as well. Flash can also be in SAS or SATA drive form-factor packages, which plug into 3.5-inch, 2.5-inch or 1.8-inch drive slots. There are also SSDs that plug into an empty DDR3 memory slot on the motherboard and connect via a SATA cable.

Server-side flash is dedicated to the server it’s installed in, meaning less flash capacity is required than with array- or network-based flash devices and implementation is simpler than in those shared storage scenarios. Although flash capacity is significantly more expensive than HDDs, SSDs caching or tiering can actually provide a lower-cost alternative, with better performance.

For VARs, server-side SSD implementation can be an ideal way to break into a new account or capture new business in an existing account that’s currently going to an array vendor. Whether implemented as a cache or tier or just a high-performance storage area, server-side flash can provide an immediate solution for a slow application.  For other use cases, an all-flash array or flash appliance may be a better alternative. We’ll look at those in another post.

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The CIO I spoke with said his biggest concern wasn’t really the BYOD movement; it was the security risk from the use of laptops outside the company — hacking or snooping at places like Starbucks and the potential for lost laptops. I had a big “Oh yeah” moment and was brought back into the real world, one I’d stopped thinking about a year or more ago. Shame on me for not focusing on the issues users have today and talking about solutions they can use. While making this mistake is a “my bad” situation for me, it’s much more serious for a VAR.

Being a year or two removed from what users are implementing is a mistake VARs can’t afford to make. They do need to bring in fresh ideas to show their clients, but they also have to keep their line cards stocked with a comprehensive set of solutions to the problems users have today. Taking the example of my discussion with the CIO above, data loss prevention (DLP) is a topic that probably got more ink from folks like me a year or two ago. It may never have scored particularly high in gee-whiz value, but it’s what he needs — and it’s what VARs should be showing him.

Other examples could be addressing performance issues on a SAN or a WAN or improving SAN troubleshooting. SSD caching and tiering are certainly collecting more than their share of attention, considering how much of those technologies users are actually buying as a percentage of their total IT spend. But there are some basic server-side SSD implementations that users should know about, like simply replacing a boot drive with an SSD.

The point is that while VARs do need to know about what’s coming up from a technology perspective, they must keep rooted in the “hear and now.” Customers want to hear about what they need now.

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Feeds and speeds instead of business cases, features instead of benefits — a lot of people trying to sell stuff in the storage space are talking about the “what” of their products instead of the “why.” As a VAR I never understood this tendency, which seemed more prevalent with vendors but was also practiced by many of those in the channel. Focusing on the why, on the business benefits of what you’re providing, is a sure way to solidify your value in end users’ minds. If Tom Cruise was a VAR and Renée Zellweger was a customer in “Jerry McGuire,” she might have said, “You had me at why.”

One of the reasons some VARs get stuck in the “what rut” is that they don’t really understand the range of technologies available or the variety of solutions that could be applied. Maybe they don’t have a complete range of products on their line cards. This is a classic vendor problem; they don’t typically sell a complete solution, which is why they (fortunately) rely on their channel partners to provide the missing pieces.

One example is SSDs. Everyone knows they’re fast and speed is something that customers are interested in, but emphasizing how SSD can increase the performance of a critical database application is the business benefit that will make the sale. There’s a lot of gray area between fast hardware and reduced processing time for an application that generates revenue for a company.

Is the solution a PCIe SSD card installed in the host, an appliance SSD solution or maybe a software accelerator that runs on the hypervisor? It doesn’t matter. All of these products can be on your line card ready to support the why discussion the customer is interested in. Get them to think about the why (reduced processing time) and you’ll take care of the what (SSDs).

How about a cloud storage example? No one really disputes the veracity of the cloud as a technology solution for a number of IT problems. Cloud solutions offer nearly limitless scale, pay-as-you-go financing, simple implementation, minimal IT overhead, etc., but there are about as many variations on the cloud theme as there are companies claiming to have a cloud solution. As a VAR, this doesn’t matter.

Armed with the knowledge that they carry all or most of the technology options available enables VARs to preach the business benefit of reduced overhead or upfront costs and ignore the distraction of the specific cloud implementation details. It’s all about value, and focusing on the why instead of the what is one of the best ways to show your value to customers.

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The old standby, storage tiering, is certainly one way to do this, and most major storage systems allow users to create a “Tier 0” for SSDs. But this method may not be able to keep up with how quickly data access requirements change, resulting in underutilized SSD investments and disappointed users. SSD caching may provide the answer.

A flash storage caching solution monitors data traffic between the CPU and storage devices and determines which subsets of data are the most active. It then copies those data blocks or files to the high-speed cache area, giving applications data access at silicon speeds. Read caching is the most common and provides the majority of performance improvements since most applications generate a much higher percentage of read than write transactions. Write caching is more complicated and requires separate steps to ensure that data is protected throughout the write process.

Flash SSD caching is typically implemented as a piece of software that runs on the host, on a PCIe card or on the RAID controller card. There are also caching solutions built into networked storage devices and even into applications. Server-based solutions typically allow any internal or server-attached SSD capacity to be used as the cache pool, making this an easier product to implement than caching solutions that only use dedicated storage capacity.

This technology has a number of advantages over tiering solutions for solving the data placement issue. Caching typically monitors data access continuously, making it a good fit for dynamic data sets that may need SSD performance for only a short period of time. Also, caching solutions are easy to implement since they’re usually application-agnostic. Most move data at the block level and don’t require APIs or integration with existing software.

At the Flash Memory Summit in Santa Clara, Calif., last week, it was all about SSD cache. Storage Switzerland was briefed by five companies that had read and write caching products. For VARs, caching can be the piece that’s been missing from their SSD solution sets. As many early users have found out, just putting SSDs into a server or storage array doesn’t magically improve performance—at least not to the extent most have expected. They need to solve the data placement question. This is one their VAR can answer, with an appropriate SSD caching solution.

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They ask VARs to show them a solution that they’ve typically done some research on (maybe) or just heard about. They don’t say, “I think my storage is causing application performance issues; what types of things can you show me to solve that?” Instead we get, “Can you show me some SSDs?” Next, you’re pulled down the path of answering whether SLC is better than MLC, whether SSD drives are better than PCIe-based SSD, or maybe even questions on the merits of SSD caching appliances vs. server-based devices. While these are viable alternatives, they may not be the best approach for a particular situation. In that case, you end up having to “unsell” the customer on a product they don’t need and start over with the options that they should really be considering.

There are a number of ways to implement solid-state storage devices within an existing infrastructure and effectively accelerate the IOPS performance of an existing disk array. But the best option may be to look at a storage array that’s 100% solid-state. This eliminates the complexity of creating an SSD tier and moving data around at the right time to maximize its effect, assuming the existing disk array architecture can sustain the needed IOPS in the first place.  

As VARs, we need to get in the door before the fun starts, so we have to respond to a lot of customer requests to show a specific product or technology. It’s often simpler to come in with a solution or two that they’re asking about and start the quoting process. But the better course of action may be to move them back from the edge. While it may seem like you’re running the sales cycle in reverse, getting them to start talking about what their problems are is the way to make sure they’ll get the best solution.

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Violin Memory’s Memory Array supports up to 10 TB of single-level cell (SLC) flash on hot-swappable, internal circuit cards the company calls “VIMMs” in a 3U enclosure. Card-mounted flash provides better density than drive form-factor SSDs, lowering the cost per gigabyte and providing better performance through the elimination of the SAS or SATA protocol. Putting more flash modules together on each card also improves the write performance, since writes can be spread over more flash modules and overhead can be done more efficiently.

Nimbus Data Systems’ dedicated flash array also puts flash modules onto hot-swappable circuit cards, or “flash blades.” A 2U array holds 24 of these blades and provides 2.5 TB of capacity. Nimbus’ HALO operating system includes storage features like snapshots and replication but also deduplication and thin provisioning. These capabilities give the system a much larger effective capacity and lower its cost per gigabyte.

Solid-state storage is moving into the dedicated array space with some compelling capabilities and price/performance numbers. These “pure flash” SSD arrays deserve a closer look by any VAR that’s serious about storage.

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