Redefining the Economics of Storage: Flash at the Price of Disk

Transcription

1 Redefining the Economics of Storage: Flash at the Price of Disk

2 Contents Redefining the Economics of Storage: Flash at the Price of Disk Contributors: Paul Rubens and Drew Robb 2 2 The State of Storage Economics in the Enterprise 5 The Common Barriers to Flash Adoption Breaking Down the Barriers to Flash Storage with Dell

3 The State of Storage Economics in the Enterprise By Paul Rubens E nterprise storage requirements are exploding as Big Data applications, increased mobile device usage and industry data retention regulations create a perfect storm of demand. This massive growth in data storage requirements has been going on for several years, and it looks set to continue for several more: Research firm IDC says that enterprise storage capacity has seen a compound annual growth rate (CAGR) of 53 percent since 2011 and predicts it will continue to grow at a similar rate at least until There are many reasons for this growth, but the rise in Big Data applications is probably the most significant one. That s because these applications increase the value of all kinds of data particularly when there is a great deal of it stretching back over a long period of time and this acts as a driver for the notion of store everything, forever. Budget Squeeze The problem for many organizations is that storage budgets have not even come close to enjoying similar growth rates. This is due in part to the difficult economic climate of the past five years. Hence, many IT departments are strapped for cash, struggling to provide enough storage capacity to keep up with demand without even beginning to think about introducing technologies to improve storage performance or efficiency. The bad news is that there are residual effects from this type of explosive growth, and they stretch storage budgets even further. At the most basic level, organizations need to store at least two copies of their data for redundancy, and the more data they store, the more backup data they have to store as well. Backing up large amounts of data also requires effective backup systems. As organizations increase their storage capacity by purchasing new NAS, SAN and other storage devices, they incur further costs adapting their backup regimes to include these new storage systems. It s also increasingly common for enterprises to have to implement ediscovery software to enable them to produce relevant documents during legal action. Although the cost of these systems is coming down, increasing volumes of stored data mean ediscovery systems are becoming more of a drain on IT budgets. (The cost of these systems is small, however, compared to the cost of manually reviewing documents produced 2 Back to Contents

4 by ediscovery systems: A 2012 Rand Corporation report estimates this at about $18,000 per gigabyte.) Investment in Performance One result of this concentration of spending on raw capacity, and the infrastructure to support it, is that other types of storage investment have often had to be abandoned through lack of funds. Mark Peters, senior analyst at Enterprise Strategy Group, says that in many cases companies have delayed buying costly solid state drive (SSD) based storage, which could increase the performance of their applications, because of the budget squeezes. But he points out that taking that approach can sometimes end up costing businesses money rather than saving it. The choice is not a simple one of capacity or performance, he points out. A well-instituted implementation of a judicious amount of solid state (whether as SSD or server cache or an all-flash array) can actually help enterprises manage budgets. That s because for applications that require a given number of input/output operations per second (IOPS), it may well cost less and stretch the budget less to use some high-performance SSDs rather than to buy large numbers of conventional spinning drives and shortstroke them to achieve the same number of IOPS. That s likely to be increasingly true in the future as SSD prices continue to fall. This lack of investment in higher performance storage systems is a problem for many organizations because applications (and users) are becoming more demanding. Real-time, data-intensive applications such as business intelligence are going mainstream as organizations seek to exploit the data they are storing, yet to get the most from them it is necessary to have storage systems offering high performance and low latency. The rise in bring your own device (BYOD) programs also means that an unprecedented number of users are accessing applications from mobile devices. This is putting further strain on storage systems. Storage Efficiency Ironically, many organizations don t actually need to use up their storage budgets buying new storage devices to increase their total storage capabilities. The reason is that it s highly likely they are not utilizing technologies such as thin provisioning, virtualization and deduplication to make the most of their existing capacity, even if they have already paid for them. There are all sorts of un-mined storage efficiency opportunities if people take the time to investigate their options and actually deploy the functions they have on existing systems, says Peters. I know from checking with some large vendors that even amongst users that have something as simple and proven as thin provisioning on their storage systems it s usually only around 50 percent that have actually turned the feature on. Increasing storage efficiency using these technologies can clearly avoid (or at least delay) the need to purchase new capacity. That also helps reduce spending on data center space, as well as the related power and cooling requirements that go with it. This lack of investment in higher performance storage systems is a problem for many organizations because applications (and users) are becoming more demanding. 3 Back to Contents

5 Another way to reduce data center related costs may be to invest in new technologies, such as helium-filled drives, that offer high-density storage (and thus take up less space), low heat generation and power consumption, and lower cost per gigabyte than existing spinning hard drives. Tiering and Cloud Organizations could also make their budgets go further if they invested in data lifecycle management and storage tiering to ensure that data is stored in the most costefficient media. More specifically, that means moving older, rarely accessed data off more costly primary storage media onto cheaper secondary media such as tape archives, less expensive disk drive types or RAID groups. There s also an argument to be made for the use of inexpensive cloud storage either for primary or secondary storage. But many organizations are unwilling to consider it, and there are a variety of valid reasons for this. Some are unwilling to entrust the security of their data to a third party, and some feel they are constrained from doing so for regulatory compliance reasons. Peters warns that organizations should take a careful look at the economics of cloud storage because in many cases the savings are not clear cut. Cloud storage tends to look price-attractive and is both granular and flexible, he says. But you have to ask questions like: What s the workload? Are you talking just storage or also processors and apps? What s the full TCO? and How do you view risk with clouds? The one thing that is clear-cut to most enterprises is that their rate of storage growth is unlikely to slacken off any time soon. Budgets may be tight, but the good news is that by implementing storage efficiency and performance technologies enterprises should be able to make them go much further. 4 Back to Contents

6 The Common Barriers to Flash Adoption By Drew Robb C omputers are like cars: the faster the better. At least, that s the first take. Most people don t turn down a Maserati because it is too fast. But they do once they look at the sticker price, the maintenance, the insurance, miles per gallon of gasoline, the reliability and the lack of cargo space. Paying extra to drive 200 mph is a waste when jammed in stop-and-go traffic during the daily commute. When it comes to purchasing their primary transportation, therefore, automobile customers will look at cost and carrying capacity, not just speed. But when there is a real advantage to speed, they will fly across the country much faster than any sports car could take them. The same rules apply to data storage. Faster is better as a general rule, but companies aren t dropping all their hard disk drives (HDDs) for more costly Solid State Drives (SSDs). But for the right applications and in the right environment, it is an effective investment. Flash may not be a panacea or a magic bullet, but it is likely to be at the heart of any solution to speed up storage, says David Hill, Principal, Mesabi Group in Westwood, Mass. Cost has been the perceived disadvantage of flash, but if used judiciously and properly that should not be the case. someone to write a report is constrained by the speed of their fingers, not the speed of their storage. When looking at costs, SSDs are not currently competing against bulk storage, but against the 15,000 RPM enterprise-class disks. Even in this comparison, however, HDDs do come out significantly better on cost per GB. If the need is speed, then use flash storage, says Larry Carvalho, principal consultant for RobustCloud, LLC. Flash is still quite expensive, but used in the right way it can be valuable. In April 2013 Gartner released a report titled Solid-State Drives Will Complement, Not Replace, Hard-Disk Drives in Data Centers in which it compared the costs of enterprise HDDs and SSDs based on vendor revenue. The report looked at two different comparisons: Enterprise Business-Critical HDD vs. Enterprise-Grade Server SSD and Enterprise Mission-Critical HDD vs. Enterprise-Grade Storage SSD. (Note: prices given below are for large-scale integrators and OEMs, not end users.) Cost and Capacity The first barrier to using SSDs is the much higher initial cost per unit of storage. But, when looking at comparative costs, keep in mind the appropriate usage scenario and when to use commodity or enterprise class storage. Companies don t run their Oracle databases on 4TB commodity drives, and the time it takes 5 Back to Contents

7 Taking the first pairing, Gartner found that the HDD prices had been relatively flat recently, going from $0.09/GB in 2010 to $0.08/GB in The SSD prices meanwhile had dropped by two-thirds over the same period, from $4.46/ GB to $1.50/GB. This resulted in the cost ratio between the two types of drives going from 49.5:1 in 2010 to 19.9:1 in Gartner estimated that costs of both technologies would continue to fall over the next five years, with SSDs hitting $0.27 in HDDs, however, were predicted to drop even faster, reaching $0.01/GB, so the SSD:HDD price ratio would remain above 20:1. It was much different for the second group. Enterprise Mission-Critical HDDs had gone from $0.43/GB in 2010 to $0.33/GB in 2012, with an estimated cost of $0.14/GB in Enterprise-Grade Storage SSDs were $8.85/GB in 2010, $2.67/GB in 2012 and an estimated $0.36/GB in As a result, the SSD:HDD price ratio continues to drop, from 20.5:1 in 2010 to 8.1:1 in 2012 to 2.8:1 in The cost of the disks themselves, however, is only one part of the overall storage cost. Since they don t have any moving parts, SSDs lower the power and cooling costs at least slightly, but the greater savings lay elsewhere. Often more compelling from a TCO perspective is the potential for server consolidation to offer a more favorable density per rack, said the Gartner report. Lastly, the improved CPU utilization can lead to server consolidation due to a reduction of performance bottlenecks, which also potentially reduce software licensing costs, providing further justification for SSD purchasing. Slow Applications A further barrier to greater SSD adoption is that most software is written for disk-based storage. True, such applications will run just as well on SSDs as on HDDs, but if just as well is the standard one is going for there is no point in paying a premium for SSDs. But software can be written to take advantage of flash memory. At the top end, databases and analytic applications are being optimized for in-memory computing. For consumers, smartphone and tablet applications are written for a flash environment. The problem is in the middle ground where software has to be written to run on any storage the customer provides. Software providers are not going to optimize their products for a small group of users. But as SSDs make their way into the data center, particularly on applications that currently make use of high speed HDDs, more applications will be written to take advantage of SSDs. Ideally, businesses shouldn t have to isolate applications on flash. Instead of investing in flash storage to be used solely by the application, for example, businesses should strive to develop an application intelligent architecture that can take advantage of flash capacity and be automatically optimized regardless of the application. Networking Bottlenecks Finally, there is the matter of networking speed. When companies began implementing server virtualization, they quickly found that even if a server had plenty of RAM, storage and processing power, the speed of its network connections limited the number of VMs that could be run on a box. Those switching to flash storage are running into a similar situation. Why invest in flash (a high-end sports car) if the highway is always congested? An application like Microsoft Exchange, for example, has very spiky demand. It s busy with users writing and extracting data when users arrive for work in the morning, and then settles down. Many businesses over-compensate by over-building their SAN for the peak usage period, but what is really needed is a network that can carry the data. Implementing a network with the speed to match the storage, such as 16 Gigabit Fibre Channel, makes sure that the investment in flash pays off. Traditional disk technology has not kept pace with CPU technology, resulting in a significant performance gap between storage and computing, said Dan Iacono, Research Director, Storage Systems for IDC. This shortfall in performance presents a huge opportunity for solid state storage to fill the void in terms of both input/output operations per second (IOPS) and latency. 6 Back to Contents

8 Breaking Down the Barriers to Flash Storage with Dell By Drew Robb F or decades, storage systems have failed to keep up with the rapid speed growth of CPUs and other data system components. Spinning disks and read/write heads just aren t as fast as silicon transistors. With the advent of flash storage and Solid State Drives (SSDs), storage systems can finally match the rest of the infrastructure. But not all companies have adopted flash storage, and it isn t due to backlash against a newer technology. The previous article, Barriers to Flash Adoption, discussed the primary reasons that companies are not taking advantage of the faster storage. Identifying any problem is a step in the right direction, but that problem still requires a solution. This article lays out what Dell is doing to make it easier and less expensive to expand the use of flash storage. Tiered Storage The first issue to address, as we discussed in the first article of this ebook, is storage growth and storage cost. As with HDDs, SSD prices have dropped dramatically over the past few years and this trend will continue. Drive sizes also increase every year. The problem is that larger drives with lower costs per GB are offset by a higher demand for storage capacity. To improve storage speed and keep up with storage growth requires implementing storage tiering so only that portion of data which requires high-speed access resides on flash while the rest can sit on lower speed, lower cost HDDs. Dell Compellent Flash-Optimized Storage Systems allow all-flash or hybrid storage in the 2U SC220 enclosure, and through the use of Intelligent Tiering provide up to a 2x price advantage over competitive hybrid-flash solutions and up to a 5x price advantage over other all-flash solutions. With Intelligent Tiering, SSD, Fibre Channel and SAS drives can be part of the same storage system, and SAS drives of different rotational speeds can reside in the same enclosure. The tiering software dynamically moves enterprise data to the optimal storage tier and RAID level based on actual use so that the most active blocks reside on high-performance SSD, Fibre Channel or SAS drives, while infrequently accessed data migrates to lower-cost, high-capacity SATA drives. Since most data goes through a lifecycle where the frequency of access declines over time, the Data Progression software migrates the data to a lower tier as the access drops off. For data residing on HDDs, the Fast Track technology dynamically places the most frequently accessed data on the fastest, or outer, tracks of each drive. 7 Back to Contents

9 This tiering is all done automatically, eliminating manual data classification and migration so storage administrators are freed up to concentrate on their own higher tier functions. Several models of Dell EqualLogic PS Series iscsi storage arrays also support SSDs, with up to GB drives per enclosure. Slow Networks A second barrier to adopting flash is that the data systems are restricted by their slowest component. While this used to be the read/write speed of disks, with SSDs that problem can move down the line into the network. To remove this barrier, for more than a decade Dell has partnered with Brocade to provide customers with integrated solutions that ensure that the network and storage are well matched. To get the most out of SSDs, there is nothing better than a 16 Gb Gen 5 Fiber Channel connection. This is one of the connection options on the SC220 Flash-Optimized enclosures. Brocade s 16 Gb Gen 5 DCX 8510 Backbones and 6500 series switches can be used to connect the Dell storage units to each other and the rest of the data center. The entry-level 6505 provides 12 or 24 ports in a 1U package, the 6510 has 48 ports and the 6520 has 96. If 16 Gb FC is not needed, the Dell Compellent SC8000 storage controller also offers a wide range of other connection options including: 2Gb, 4Gb and 8Gb FC; 1Gb and 10Gb iscsi; 6Gb and 6Gb SAS; and 10Gb FCoE. Brocade has switches to match these other options. Several models of Dell EqualLogic PS Series iscsi storage arrays also support SSD, with up to GB drives per unit. Not All Flash is the Same Finally, let s take a look at the type of flash that is used in a storage array. Dell partners with SanDisk, which builds the drives used on the flash arrays. Not all SSDs use the same technology. To get the most value out of flash storage is it important to select the right technology for the right application. There are two basic types of types of SSDs: SLC and MLC. Single-level Cell (SLC) flash stores one bit of data in each cell of flash media, a zero or a one, which makes it faster to interpret and which lowers the chance of errors. Each individual memory cell can be written to about 100,000 times, making it ideal for high-speed write-intensive operations. Multi-level Cell (MLC) flash, on the other hand, stores more than one bit per cell. This allows more data to be stored on a flash drive, greatly lowering the cost per GB. However, MLC is more prone to error than SLC flash and also has many fewer write cycles than SLC. A two-bit MLC cell will start to fail after about 3,000 to 10,000 write cycles and a three-bit cell after about 300 to 3,000 cycles. There is also emlc (Enterprise Multi-Level Cell) flash with two-bit cells that are good for 20,000 to 30,000 writes. Through its partnership with SanDisk, Dell offers customers the choice of both SLC and MLC SSDs. Both types can be used in the same system with Compellent Storage Center Version 6.4 s auto-tiering function deciding which type of SSD to use. This approach with SSDs is similar to the way storage software can choose between high-speed, low-capacity SAS drives and slower but larger SATA drives. Write-intensive data such as databases would go to the SLC drives while functions such as file serving can be done off the MLC drives without worrying about exceeding their write-cycle limits. These higher capacity MLC drives allow 1.6TB of flash storage to fit in a single 2.5-in. drive bay. Using both types of drives allows customers to achieve the benefits of SSD storage at a lower cost than if they were restricted to using only SLC flash. With these innovations, the main barriers to achieving the full benefits of flash storage, at an affordable price have been resolved. For more information on Dell Compellent Flash-Optimized storage visit flashstorage or contact your Dell sales representative. 8 Back to Contents