Deploying Affordable, High Performance Hybrid Flash Storage for Clustered SQL Server

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1 Deploying Affordable, High Performance Hybrid Flash Storage for Clustered SQL Server Flash storage adoption has increased in recent years, as organizations have deployed it to support business applications. PCIe flash memory is dramatically faster than solid-state drives and unique QoS technology from NexGen Storage guarantees predictable application performance. IT teams can maximize SQL Server performance through storage best practices, including the use of flash storage. ESG found that NexGen s end-to-end flash storage solution significantly improved performance in SQL Server clustered environments. By delivering enhanced database application performance, NexGen s PCIe flash solutions reduce IT costs and improve business operations. Michael Otey, Senior Technical Director, Windows IT Pro, SQL Server Pro Mike Leone, Lead Lab Analyst, ESG Vincent LaPaglia, Senior Storage Engineer, NexGen Sponsored by:

2 Overview In recent years, flash storage implementation options have increased and many organizations now use this technology on servers to improve application performance. In SQL Server environments, flash storage eliminates many traditional storage controller and protocol bottlenecks. It is well suited for data files, log files, indexes, and tempdb. Lab validation by ESG found that the NexGen and NexGen SPX products increased average response times and supported many more transactions per second than traditional SANs. Context The panelists described how flash storage solutions like those offered by NexGen can improve performance for clustered SQL server environments. close to half of organizations (49%) use solid-state drives in external disk storage subsystems, and almost half (48%) use solid-state storage technology as extended cache, memory, or primary storage within servers. If we fast forward to today, we find that flash storage is used heavily in modern data centers. The primary reason is the increased number of implementation options. More organizations are using flash technology to meet their application requirements. Mike Leone Key Takeaways Flash storage adoption has increased in recent years, as organizations have deployed it to support business applications. When flash or solid-state storage was first introduced, its primary benefit was performance. A survey by ESG found that over one third of respondents (36%) said improved performance drove their organizations initial deployment of solid-state storage. However, early adoption was slow due to cost. Today flash storage is used heavily in modern data centers, due to the increased number of implementation options. ESG discovered that End user needs have driven the use of flash storage on servers, closer to applications. An ESG survey found that over half of respondents (52%) said OLTP business applications are driving their organizations to deploy solid-state storage. Application end users always want enhanced performance, higher efficiency, and a better application experience. Flash storage technology can deliver on all these dimensions. PAGE 2

3 NexGen s PCIe flash is dramatically faster than solid-state drives and its unique QoS technology guarantees predictable application performance. Integrating solid-state drives (SSD) into storage arrays can generate performance gains on the back end. However, in many cases, the technology is still bottlenecked by traditional RAID and controller throughput. NexGen addressed these challenges by using flah placed on the PCIe bus providing consistent, best-in-class PCI flash performance. The technology is up to 40 times faster than traditional SSDs. Vincent LaPaglia described the important elements of NexGen s product portfolio: NexGen N5 Hybrid Flash Array. The NexGen N5 combines high performance PCIe flash and efficient spindle storage into a low-cost, high-performance storage array. NexGen N5 SPX Solutions. SPX combines the NexGen N5 with SanDisk ioturbine software. The result is an out-ofthe-box solution that can be used for highly available applications like SQL clustering and three-plus node virtualization. NexGen s unique differentiator is its QoS (Quality of Service) technology. QoS technology guarantees predictable application performance. Two key benefits are: 1. Built-in QoS policies provision performance and the array handles the IO prioritization. The NexGen software and real-time data placement eliminate the need to dedicate array resources for a singular need. That is a major advantage from an architecture, engineering, and administration standpoint. 2. It is possible to guarantee performance levels for many high-performance application workloads. Within a QoS performance policy, a minimum IOPS and a not-to-exceed latency can be guaranteed. By designating different systems as mission critical, business critical, and non-critical, IT teams can assign storage volumes to each and eliminate contention. The NexGen secret sauce... is the QoS technology. Our Quality of Service technology guarantees predictable performance for applications by prioritizing which workloads are assigned to performance policies. Vincent LaPaglia IT teams can maximize SQL Server performance through storage best practices, including the use of flash. SQL Server is different from file server systems. As a result, unique attributes must be considered when designing storage for SQL Server. Michael Otey discussed five storage challenges related to SQL Server: 1. Performance requirements. Today s users and applications have more intense performance requirements than ever before. As a result, it is essential to select a storage subsystem technology that meets the organization s performance needs. PAGE 3

4 2. Database and log files configuration. With database servers, database and log files have different purposes and a single database may contain multiples of these files. The configuration of database and log files can have a significant impact on SQL Server performance. 3. Data availability. It is important to design for high data availability levels. This is as important as performance. If users can t access a database, it doesn t matter how quickly it performs. 4. Backup and restore. Organizations must be able to back up and restore their databases if disasters occur. 5. Efficiency. When it comes to storage, IT teams strive to be as efficient as possible and not spend more than is necessary. These challenges can be addressed by implementing several best practices: Segregate database and log files onto separate drives. By default, SQL Server puts both database and log files on the same drive as the SQL Server binaries. That is undesirable from a performance perspective because all the I/O is funneled through the same drive. A best practice is to separate the data and log files. Since log files get a lot of write activity, they should be placed on fast writing drives, such as RAID 1 or 10 drives. This approach also provides data protection for log files Enable AutoGrow, but don t depend on it. AutoGrow prevents databases from shutting down if they hit their maximum sizes. While this is a good safety mechanism, performance takes a hit every time the database has an AutoGrow operation. Organizations should be proactive and manually size their databases to minimize the chance that AutoGrow will be invoked. Using AutoShrink is not advised. Enable instant file initialization. This avoids zeroing out allocated space. Instant file initialization is set through a Windows Server Policy. Size tempdb properly and store it on its own drive. Tempdb is a SQL Server global resource that is available to all users. It contains internal database engine objects such as joins, aggregations, XML and LOB data, cursors, sorting, hashing, and row versioning. Sizing tempdb is essential to avoid AutoGrow. By default tempdb is only around 8 megabytes, but it can be resized using the ALTER DATA- BASE command. When SQL Server is restarted, it sets tempdb to its last configured size. Ideally tempdb should be maintained on its own RAID 10 or better drive. Flash storage is an excellent solution for tempdb. The SQL Advisory Team recommends that enterprise scale databases use one data file per core for tempdb. Be aware of SANs physical implementation. SANs can be a good solution for storing SQL user databases. They offer high performance, scalability, high availability, clustering, snapshots, replication, and disaster recovery. Since they have a good reputation for data tiering, they are suitable for larger databases. However, it PAGE 4

5 is important to understand the physical implementation. Find out how LUNs are configured and make sure all I/O isn t funneled through one LUN. By maintaining data files, log files, and tempdb on different drives, it is possible to split out I/O and maximize performance. Use flash to accelerate SQL Server performance. CPUs have become faster and memory has become cheaper. Disks, however, haven t gotten much faster. As a result, I/O bottlenecks can occur. Since flash is much faster than rotational disks, it can help with performance. Consider the following statistics: - A 15K rpm SAS drive can offer about -150 to 200 MB/sec of sequential throughput. - A 6 Gbps SATA or SAS solid-state -drive can provide about 550 MB/sec of sequential throughput or about 100,000 IOPS random read and write. - PCIe flash offers about 2 GB/sec of -sequential throughput and 250,000 IOPS random read and write. PCIe flash eliminates many of the traditional storage controller and protocol bottlenecks. Unlike SSD drives, PCIe flash doesn t need to emulate what a disk would look like. This results in better performance and more efficient I/O. PCIe flash isn t a silver bullet, however. It cannot fix incorrect sizing, lack of memory, or slow queries. It is best for heavy, random I/O activity. Flash storage is well suited for data files, log files, indexes, and tempdb. To maintain flash drive performance, keep utilization slightly below 75%. Many times with powerful and memory-rich systems, disks become the bottleneck. Flash technology is a simpler answer than implementing a SAN. Flash storage can be dedicated to SQL Server and provide much better performance. Michael Otey ESG found that NexGen s end-to-end flash storage solution significantly improved performance in SQL Server clustered environments. ESG recently conducted a lab validation that simulated real-world OLTP workloads running on a SQL Server cluster. The tests measured IOPS, latency, and transactions per second. Three storage scenarios were modeled: 1. Traditional. This included a SAN attached array with SAS hard drives and no flash. 2. NexGen. This included a SAN attached hybrid array with SAS drives and PCIe flash. 3. NexGen SPX. This included an end-toend flash hybrid storage solution using PCIe flash and ioturbine software in a pair of servers, as well as a SAN attached NexGen array with PCIe flash and SAS hard drives. The first phase of testing measured the total achievable IOPS and average latency from a simulated OLTP workload. Mike Leone described the key takeaways: PAGE 5

6 From an IOPS standpoint, NexGen and NexGen SPX provided a 4 to 5.5 times performance improvement over traditional SAN. The traditional SAN architecture peaked at little more than 17,000 IOPS, while NexGen and NexGen SPX peaked at around 69,000 and 93,000 respectively. number of concurrent users increased from 2 to 72. NexGen supported 9 times the number of transactions per second as traditional SANs, while NexGen SPX supported 10 times the number of transactions per second. Latency analysis showed that NexGen delivered a significant increase in average response time. When compared to a traditional SAN, NexGen offered 4.2 times faster response times, while Nex- Gen SPX provided a 6 times improvement (see chart below). The NexGen solutions increase productivity and customer satisfaction, as end users demand faster, more responsive application experiences. Moving flash storage closer to where applications reside creates a performance boost. Testing found that NexGen SPX boosted performance boost for the IOPS associated with applications. By offloading IOPS to the server-based flash storage, more array IOPS can service additional SQL Server workloads. This is important when multiple mission-critical applications are running on the same underlying storage subsystems. Under concurrent user loads, the NexGen solutions supported many more transactions per second than traditional SANs. Using an SQL Server OLTP simulation, the number of transactions per second was measured as the PAGE 6

7 By delivering enhanced database application performance, NexGen PCIe flash solutions reduce IT costs and improve business operations. Improving application performance is an important objective for IT administrators. This is especially true for mission-critical database applications that support business operations. Performance problems can lead to decreased productivity, unhappy customers, and lost revenues. Unfortunately, as more diverse workloads are added to the IT infrastructure and leverage the same underlying storage infrastructure, I/O bottlenecks emerge. Usually, IT admins over-purchase and over-provision storage, which adds complexity to the system. In addition, this approach is less appealing as IT budgets shrink. By placing PCIe flash at the right place and the right time, mission-critical applications experience a significant performance boost. This is a cost-effective way to increase storage infrastructure efficiency. NexGen hybrid flash arrays enable higher application density, greater efficiency, and an improved user experience. PAGE 7

8 Biographies Michael Otey Senior Technical Director, SQL Server Pro Michael Otey is senior technical director for Windows IT Pro and SQL Server Pro and is president of TECA, a technical writing, softwaredevelopment and consulting company in Portland, Oregon. Michael covers the topics of SQL Server, Windows Server, VMware vsphere, virtualization, PowerShell and.net development. Michael performs hardware and software product reviews for the Windows IT Pro labs. He does frequent webcasts, is a presenter at IT/Dev Connections and other conferences and has written several books on SQL Server and.net development. Vincent LaPaglia Storage Engineer - Technical Marketing, NexGen Vincent LaPaglia has 18 years in the IT industry with 12+ years of storage architecture, design and implementation experience. Proficient in a wide range of storage technologies, as both an end-user and as a consultant, he is a graduate of Syracuse University and currently makes his home in Colorado. He joined NexGen last year as a Senior Storage Engineer. Mike Leone Lead Lab Analyst, ESG Enterprise Strategy Group is an IT analyst and strategic consulting firm anchored in end-user market research and hands-on testing. Mike Leone, a lead lab analyst, works in one of ESG s major practices, ESG Lab, which provides in-depth testing and analysis of IT technology and products, using methods that simulate or recreate real-world environments. 2014, Penton Media, Inc. All rights Reserved. PAGE 8