Accelerate SQL Server 2014 In-Memory OLTP Performance with Dell PowerEdge R920 and Express Flash NVMe PCIe SSDs

Transcription

1 Accelerate SQL Server 2014 In-Memory OLTP Performance with Dell PowerEdge R920 and Express Flash NVMe PCIe SSDs This technical white paper discusses performance improvements of SQL Server 2014 In-Memory databases by using the Dell PowerEdge R920 and Express flash NVMe SSDs. Gopu Narasimha Reddy Dell Engineering August 2014 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe PCIe SSDs

2 Revisions Date August 2014 Description Initial release THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL INACCURACIES. THE CONTENT IS PROVIDED AS IS, WITHOUT EXPRESS OR IMPLIED WARRANTIES OF ANY KIND Dell Inc. All rights reserved. Reproduction of this material in any manner whatsoever without the express written permission of Dell Inc. is strictly forbidden. For more information, contact Dell. PRODUCT WARRANTIES APPLICABLE TO THE DELL PRODUCTS DESCRIBED IN THIS DOCUMENT MAY BE FOUND AT: Performance of network reference architectures discussed in this document may vary with differing deployment conditions, network loads, and the like. Third party products may be included in reference architectures for the convenience of the reader. Inclusion of such third party products does not necessarily constitute Dell s recommendation of those products. Please consult your Dell representative for additional information. Trademarks used in this text: Dell, the Dell logo, Dell Boomi, Dell Precision,OptiPlex, Latitude, PowerEdge, PowerVault, PowerConnect, OpenManage, EqualLogic, Compellent, KACE, FlexAddress, Force10 and Vostro are trademarks of Dell Inc. Other Dell trademarks may be used in this document. Cisco Nexus, Cisco MDS, Cisco NX- 0S, and other Cisco Catalyst are registered trademarks of Cisco System Inc. EMC VNX, and EMC Unisphere are registered trademarks of EMC Corporation. Intel, Pentium, Xeon, Core and Celeron are registered trademarks of Intel Corporation in the U.S. and other countries. AMD is a registered trademark and AMD Opteron, AMD Phenom and AMD Sempron are trademarks of Advanced Micro Devices, Inc. Microsoft, Windows, Windows Server, Internet Explorer, MS-DOS, Windows Vista and Active Directory are either trademarks or registered trademarks of Microsoft Corporation in the United States and/or other countries. Red Hat and Red Hat Enterprise Linux are registered trademarks of Red Hat, Inc. in the United States and/or other countries. Novell and SUSE are registered trademarks of Novell Inc. in the United States and other countries. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Citrix, Xen, XenServer and XenMotion are either registered trademarks or trademarks of Citrix Systems, Inc. in the United States and/or other countries. VMware, Virtual SMP, vmotion, vcenter and vsphere are registered trademarks or trademarks of VMware, Inc. in the United States or other countries. IBM is a registered trademark of International Business Machines Corporation. Broadcom and NetXtreme are registered trademarks of Broadcom Corporation. Qlogic is a registered trademark of QLogic Corporation. Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and/or names or their products and are the property of their respective owners. Dell disclaims proprietary interest in the marks and names of others. 2 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

3 Contents Revisions... 2 Executive Summary Introduction Microsoft SQL Server 2014 In-Memory OLTP Database Main Memory optimized data structures for high performance Natively compiled stored procedures for efficient business-logic processing High Concurrency for frictionless scale-up Integration of In-Memory database engine into traditional SQLServer database engine for hybrid and integrated experience Dell PowerEdge R920 & NVMe based PCIe Flash drives to accelerate performance of Hybrid OLTP Engine NVMe PCIe Flash drives support on Dell PowerEdge R Advantages of using Dell PowerEdge Express Flash NVMe PCIe drives for In-Memory OLTP engine Test configuration Test methodology Performance results and analysis Performance improvements using Dell Express Flash NVMe PCIe SSD drives Conclusion Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

4 Executive Summary Today s Online Transaction Processing (OLTP) based applications such as online reservations, stock market, and process control need real-time access to data. The traditional disk-based OLTP systems cannot keep up with the requirements of today s applications, therefore, there is a continuous requirement for alternate low- cost OLTP systems that can deliver higher throughput at lower latency. By leveraging the modern hardware trends and recent technology advancements, many of the software vendors introduced several In-Memory OLTP systems to the market. SQL Server 2014 In-Memory database is one such product from Microsoft. It is a high performance OLTP database engine that is designed and optimized for processing In-Memory data. This technical white paper will explore the Microsoft SQL server 2014 In-Memory database feature and showcase the performance benefits that can be achieved by deploying it on the Dell PowerEdge R920 server and NVMe-based PCIe flash drives. You are presented with guidelines and best practices for configuring SQL Server 2014 In-Memory databases and the test results that were conducted at Dell Labs. The key results of this white paper are shown in the snapshot here. Figure 1: Comparing SQL Server 2014 In-Memory VS traditional disk-based databases on Dell platform 4 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

5 5 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

6 1 Introduction In the past, because of expensivie memory chips, the traditional Relational Database Management Systems (RDBMS) were designed to have data stored on physical disk drives for persistence and bring data in to memory when needed for serving query requests. Over a period of time, there has been a steady decline in memory prices coupled with increases in the memory capacity. It is now very common to see modern high-end enterprise servers supporting several tera bytes of memory. In addition to this, today s latest microprocessors contain multiple processor cores and the number of cores available with each new processor release are expected to grow steadily. Because of the legacy design, the traditional database systems may not leverage the mutli-core processors efficiently and effectively. On the other hand, there has been a continuous need for extreme performing systems required by today s software applications which need real-time access to data. Customers are constantly looking for high performing and low-cost OLTP solutions that address their challenges by leveraging these modern hardware trends and advancements. This paper discusses the OLTP performance benefits that customer can gain from SQL Server 2014 In- Memory databases when deployed on Dell PowerEdge R920 server along with NVMe flash cards when compared with traditional disk-based OLTP databases. 6 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

7 2 Microsoft SQL Server 2014 In-Memory OLTP Database Microsoft introduced In-Memory OLTP transaction processing as part of SQL Server The In- Memory database engine is fully integrated into SQL server and runs side-by-side with the traditional database engine. The In-memory engine allows us to create memory optimized tables to be stored in main memory so that the OLTP workload can access this memory resident data much faster. The In-Memory database engine helps improve performance of OLTP applications significantly by using the following mechanisms. 2.1 Main Memory optimized data structures for high performance The In-Memory database engine does not use the traditional B-tree based data page structures for storing indexes and therefore there is no caching of data pages in buffer cache of SQL database engine. The In- Memory database engine uses either hashing indexes or memory-optimized non-clustered indexes for storing the tables in the memory. Hash indexes are efficient for item lookups while the memory-optimized non-clustered indexes are efficient for range searches. To achieve the data durability of these memoryoptimized tables, the In-Memory database engine creates a set of checkpoint files (combination of Data and Delta files) on stream-based storage which keep track of changes to data residing in the memory. The checkpoint files are recommended to store on storage volumes which are optimized for sequential access. This stream-based storage helps reduce the Recovery Time Objectives (RTO) of the memoryoptimized tables. 2.2 Natively compiled stored procedures for efficient business-logic processing With CPU speeds being flattened at 3GHz, the In-Memory database engine uses a different approach to reduce the number of CPU instructions to be executed in order to process the same user query. The In- Memory database engine achieves this by converting the interpreted T-SQL code or stored procedures into natively compiled Win64 code. Natively compiled code allows faster access and more efficient query execution than interpreted (traditional) T-SQL code. The combination of In-Memory database engine and natively complied stored procedures are the primary factors driving the high performance In-Memory OLTP engine. 2.3 High Concurrency for frictionless scale-up As In-Memory database engines get rid of the page structures by using hash indexes, the locking, and latching mechanisms are not applicable to memory resident data. Instead, it uses a new optimistic multiversion concurrency control mechanism in conjunction with the alogorithms that have been optimized for memory resident data. When a row is modified, the In-Memory database engine makes an entirely new version of that row and timestamps it. The In-Memory database engine uses a new lock-free garbage collection process to clean up the unwanted versions of data rows. Later, the engine analyzes and validates any updated rows before it commits them. All these actions are very fast as they are done entirely in memory only. This design offers high concurrency and frictionless scalability over traditional SQL server 7 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

8 database engine because there are no locks or other latch waits that may prevent the database from running at full speed. 2.4 Integration of In-Memory database engine into traditional SQLServer database engine for hybrid and integrated experience In-Memory database engine is fully integrated into the SQL Server which will allows customers to gradually migrate their most performance-critical, disk-based tables to memory-optimized tables and gain the significant performance improvement. This implies that we can have hybrid experiences where the memory-optmized and traditional disk-based tables can co-exist within the same database. The diskbased tables will be cached using regular SQL Server bufferpool inside memory; whereas, the memoryoptimized tables reside in their own dedicated memory areas. This integration offers users the same manageability, administration, development experience, and also integrated high availability (using Always-on feature) and backup or restore options. It offers customers with lower Total Cost of Ownership (TCO) as there is no need for skilled administrators and other thirdparty software to manage the In-Memory databases. For more details about the points discussed earlier here, refer the Microsoft website With above performance driving factors, the SQL Server 2014 In-Memory database engine is well positioned to take full advantage of the changing hardware trends and modern application requirements. By leveraging the recent hardware trends, the Dell PowerEdge R920 server has been designed with the latest multi core Intel processors, multi-terabyte memory support, and with high speed flash-based local storage. At Dell labs, we have explored In-Memory database engine and experimented with accelerating the In-Memory database performance even more against traditional disk-based SQLServer engine by using Dell PowerEdge R920 server and NVMe-based PCIe flash drives. The following sections discuss the hardware infrastructure used and performance gains achieved by using the high performing enterprise servers and flash drives. 8 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

9 3 Dell PowerEdge R920 & NVMe based PCIe Flash drives to accelerate performance of Hybrid OLTP Engine PowerEdge R920 server is a compute-intensive rack server designed to run mission-critical applications for mid-sized and large enterprises. The followings diagram list the technical specifications of PowerEdge R920 server. Figure 2: PowerEdge R920--Front View For detailed specifications, see the product page. 9 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

10 Figure 3: PowerEdge R920 Technial Specifications Snapshot Intel Xeon processor E v2 and E v2 product family Upto 37.5 MB L3 cache QPI of 8.0 GT/s Upto physical 60 cores, when fully loaded Memory (Disk Space) RDIMMs and LRDIMMs at DDR3 (1.5V) and DDR3L (1.35V) voltage specifications Single, Dual, Quad, and Octal rank DIMMs up to 1600 MT/s Upto 96 DIMMs supporting upto 6 TB with LRDIMMs and 1.5 TB with RDIMMs NVMe PCIe Flash drive support and hybrid Drive Backplanes Up to inch 1.6TB front-accessible Express Flash NVMe PCIe SSD (PCIe 3.0) Up to inch hot-plug 12Gb/6Gb SAS HDD or SAS/SATA SSD Supports 2.5 SATA/SAS SSD, SAS HDD (15K, 10K), nearline SAS HDD (7.2K) and 2.5 Dell PowerEdge NVMe Express Flash PCIe SSD I/O Slots Up to 10 PCIe slots; 8 PCIe 3.0, + 1 RAID slot, + 1 NDC slot + 2 optional PCIe slots The Dell PowerEdge R920 is powered by next generation of Intel Xeon processor E7 v2 product family 1. It is a 4-socket 4U rack server, ideal for mission-critical applications, and high performing workloads. PowerEdge R920 supports upto 30 physiscal core in half-loaded configuration and upto 60 physcial cores in full-loaded configuration. With upto 60 physical cores, PowerEdge R920 server provides abundant computing power for compute-intensive hybrid OLTP engine. PowerEdge R920 supports a maximum of 6 TB Memory. Memory-intensive applications such as In- Memory databases enegines and traditional SQL Server engines benefit by greater memory capacity and higher memory bandwidth and deliver more performance in less time. This memory capacity enables the PowerEdge R920 to run SQL Server 2014 In-Memory and traditional database engines seamlessly on a single host server Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

11 PowerEdge R920 supports upto ten PCIe slots for network interface cards (NICs) or Host Bus Adaptors (HBAs). With support of up to 10 PCIe slots, it provides flexibility to get started with a minimal number of network cards, and then scale up when required. This helps to reduce the network latencies and improve the network bandwidth. 3.1 NVMe PCIe Flash drives support on Dell PowerEdge R920 Non-Volatile Memory Express (NVMe) defines an optimized interface and command set for accessing Solid State Drives (SSDs) attached through PCIe bus. The goal of NVMe is to unlock the potential of PCIe SSDs and to standardize the PCIe SSD interface. NVMe is architected from the ground up for faster access of PCIe-based non-volatile devices. NVMe PCIe-based flash drives drastically improve both random and sequential read/write operations required by enterprise applications such as high throughput OLTP database systems. Dell PowerEdge R920 is the first server in the industry to ship with NVMe PCIe SSDs. A single PowerEdge R920 supports up to eight hot-pluggable PowerEdge Express flash NVMe PCIe SSDs. These drives are designed for applications that require ultra-low latency, high Input/Output operations per second (IOPS), and enterprise-class storage reliability and serviceability. The table here shows technical specifications of PowerEdge Expressflash NVMe PCIe SSDs. Table 1 Dell PowerEdge Express flash NVMe SSDs details Feature Capacity Interface Sequential Read/Write Random Read/Write Latency Express Flash NVMe PCIe SSDs 400 GB, 800 GB, and 1600 GB PCIe 2.0 and PCIe 3.0 compliant Up to 3.0/1.4 GB/S 700,000+ / 125,000 IOPs <40 MicroSec With a choice of 400GB, 800GB, and 1.6TB capacities, PowerEdge Express Flash NVMe PCIe SSDs interact with, and optimize high-performance NAND, achieving ultra-high IOPs and sequential read/write speeds. Express Flash NVMe PCIe SSDs deliver exceptional performance in demanding enterprise application environments, such as online transactional processing (OLTP) databases and virtualization workloads. For more details about Dell PowerEdge express flash NVMe SSDs, click the link. 11 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

12 3.2 Advantages of using Dell PowerEdge Express Flash NVMe PCIe drives for In-Memory OLTP engine Irrespective of how powerful the database engine is, the overall performance always depends on the underlying hardware infrastructure. As discussed in the earlier sections, it is evident that the In-Memory OLTP engine has an efficient and high performing engine which can generate high volumes of transactions. In a fully recovered database environment, every data modification is recorded in the transaction log (T-Log) buffer, and then hardened to transaction logs stored on hard drives. The high volume transaction systems generate extreme disk I/O operations on the database transaction log files. The I/O operations on transaction log can become the bottleneck when it is not placed on high performing hard drives such as SSDs. Keeping the transaction log files on rotational hard drives may cause many I/O waits and underutilization of CPUs. The performance get impacted even more when underlying disks are not write-performant because transaction logging activity mostly involves writes to the disk drives. In addition to the transaction logging activity, In-Memory database engine uses checkpoint files to meet the persistence requirements of the in-memory data. An offline checkpoint process keeps track of inserts and deletes of In-Memory data by using data and delta files. This generates considerable amount of sequential disk I/O activity. Storing these checkpoint files on high performing drives improves the overall system throughput. The Dell PowerEdge Express flash NVMe PCIe SSDs provides the ultra low-latency and high, read and write performance required by transaction logging, and checkpoint activities of In-Memory databases. The following sections go into more detail about performance benefits achived by using NVMe PCIe SSDs. 12 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

13 4 Test configuration The objective of the test configuration was to demonstrate the performance benefits of using SQL Server 2014 In-Memory OLTP feature being deployed on Dell PowerEdge R920 servers along with the transaction log files and memory optimized file groups being stored on Dell Express Flash NVMe PCIe SSDs. We also compare the performance achieved with In-Memory engine with traditional SQLServer database engine. The table here describes the test configuration details of PowerEdge R920 using NVMe PCIe SSDs. Table 2 Component Server Test Environment configuration Details Dell PowerEdge R920 BIOS:1.2.2 Processors 4 Intel Xenon CPU E Cores each Total number of Cores 60 Memory Back plane and RAID Controller Storage for OS deployment 32 16G DIMMs Total 512 GB Operating at 1333 MHz 12Gbps 16+8 SSDs backplane Dell PowerEdge RAID Controller PERC H730P Package: Firmware: A RAID1 Volume using two 300G 10,000 RPM drives for Operating System deployment Storage for SQL Server database files A RAID10 Volume using four 146G 15,000 RPM drives for Storing SQL Server database files NVMe Flash drives Operating System One Dell Express Flash NVMe XS GB capacity Driver version: A single volume created using NTFS file system for storing Memory-Optimzed file group & Transactional Log files (T- Log) Windows 2012 R2 Datacenter Edition Database SQL Server 2014 Enterprise Edition Build Version Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

14 Microsoft Windows 2012 R2 is installed on the PowerEdge R920 system. SQL Server 2014 is installed on the server with default settings. A sample database is created and its data files are stored on a RAID10 volume which is created using four 146G 15,000 RPM SAS drives. TempDB data and log files are also stored on the same RAID10 volume. File stream-based Memory Optimized file group is added to sample database and is stored on the Dell Express Flash NVMe 1600 GB SSD drive. 4.1 Test methodology We used OStress tool which is a Microsoft tool that comes with RML utilities package and is used to stress SQL Server. With the help of this tool, we can simulate high volumes of insert and update operations on the underlying SQL Server tables. It allows us to specify the number of threads to execute the statements in parallel. After excecution finishes for all threads, it will display the time taken for all the threads fo finish the execution. Tasks implemented to evaluate the performance of In-Memory OLTP performance: Created a sample database and configured with file stream-based file group on Dell NVMe flash drive which is required for storing memory-optimized tables for data persistence. Initially, all the data and Transaction Log files of the sample database are stored on rotational local storage of the server. Even the TempDB database files are located on local storage of the server. Stressing Disk-based tables of traditional SQL server engine. We first stressed the disk-based tables of traditional SQL Server database engine by using OStress tool by a inserting 10,000,000 records using 100 threads, each inseting 100,000 records. Required performance metrics are captured during the test run. Moved the Transaction Log files to Dell Express Flash NVMe PCIe 1600GB SSD drive. Repeated the same test as above and captured the required performance metrics. Stressing Memory-Optimized tables of In-Memory database engine. Initially the Transaction log file of the database is stored on the rotational drives. With the same workload, we have stressed the memory optimized In-Memory database tables. We moved the Transaction log files of the sample database to Dell Express Flash NVMe PCIe 1600GB SSD drive. We repeated the same tests mentioned above and captured the required performance counters. 14 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

15 5 Performance results and analysis The following sections provide the performance benefits of SQL Server In-Memory databases running on Dell PowerEdge R920 server in conjuction with NVMe PCIe SSDs. 5.1 Performance improvements using Dell Express Flash NVMe PCIe SSD drives The table here compares the performance SQL Server 2014 disk-based tables against SQL Server 2014 memory optimized table being deployed on PowerEdge R920 and Dell Express Flash NVMe PCIe drives. Table 3 OLTP Performance improvements using PowerEdge R920 and Express Flash 1600GB SSD drive Time taken for disk-based tables (mm:ss) Time taken for Memory-Optimized tables(mm:ss) Test#1 Test#2 Test#3 Test#4 WorkLoad T-LOG files T-LOG files on Dell T-LOG files on Dell on T-LOG files on Express Flash NVMe Express Flash NVMe rotational rotational drives 1600GB SSD 1600GB SSD drives Inserting 10,000,000 records with 100 threads each inserting 100,000 63:38 21:56 8:05 01:30 During the workload test, when the T-LOG files placed on rotational drives, we observed huge I/O waits on T-LOGs files (around 80% WRITELOG waits) in both the tests 1 and 3. When moved to Dell Express Flash NVMe PCIe SSDs, the I/O waits on T-LOG files have been elevated and that has caused around 3x and 5x times performance improvement in the respective test cases. 15 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

16 The figure here depicts the time taken by the four test cases to complete the given OLTP workload. Figure 4: OLTP performance improvments using SQL Server 2014 In-Memory database feature and Dell PowerEdge R920 along with Dell Express Flash NVMe 1600GB PCIe SSDs. Figure 5 shows Transactions Per Second (TPS) created for each test case. Figure 5: Troughput comparision of traditional Vs In-Memory SQL engine database tables 16 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

17 Figure 6 shows the response time of Dell Express Flash NVMe PCIe SSD card when compared to rotational 15,000 RPM SAS drives during the workload tests 3 and 4. Figure 6: Dell Express Flash NVMe 1600G PCIe SSD drive response time comparision Figure 7 compares the number of transaction log records written to transactional Log (T-Log) file of the sample database when the log file placed on rotational hard drives Vs Dell NVMe flash drive. Figure 7: Comparison of transaction log records written per Second 17 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

18 And lastly, the figure 8 shows the CPU utilization of the PowerEdge R920 server during the workload tests. Figure 8: CPU utilization report 18 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs

19 6 Conclusion Dell PowerEdge R920, coupled with Express Flash NVMe PCIe SSDs, provides the right platform for deploying SQL Server 2014 In-Memory databases. Powered by intel Xenon V2 E7 product family processors, the R920 provides superb computing power required by high volume transactional databases. Support of Express Flash NVMe PCIe SSDs on R920 will eliminate the IO waites and boost the performance of IO intensive database OLTP workloads. The following figure shows the benefits of deploying SQL Server 2014 In-Memory databases on Dell PowerEdge R920 along with Express Flash NVMe PCIe 1600GB SSD drive against the traditional database engine. Figure 9: Performance improvements using Dell PowerEdge R920 and Express Flash NVMe 1600G SSD drive 19 Accelerate SQL Server 2014 In-Memory OLTP performance with Dell PowerEdge R920 and Express Flash NVMe SSDs