EMC XTREMIO WORKLOAD CONSOLIDATION AND COPY MANAGEMENT FOR MICROSOFT SQL SERVER Virtualize and consolidate OLTP and OLAP instances with consistent performance Reduce SQL Server storage footprint with XtremIO inline data reduction capabilities Simplify DevOps with EMC AppSync management for XtremIO Virtual Copies EMC Solutions Abstract This white paper describes the operational advantages of virtualized Microsoft SQL Server 2012 and 2014 databases deployed on an EMC XtremIO all-flash array, and demonstrates how the solution enhances the capabilities of SQL Server databasedependent environments. December 2015
Copyright Copyright 2015 EMC Corporation. All rights reserved. Published in the USA. Published December 2015 EMC believes the information in this publication is accurate as of its publication date. The information is subject to change without notice. The information in this publication is provided as is. EMC Corporation makes no representations or warranties of any kind with respect to the information in this publication, and specifically disclaims implied warranties of merchantability or fitness for a particular purpose. Use, copying, and distribution of any EMC software described in this publication requires an applicable software license. EMC 2, EMC, AppSync, Avamar, Connectrix, X-Brick, XtremIO, and the EMC logo are registered trademarks or trademarks of EMC Corporation in the United States and other countries. All other trademarks used herein are the property of their respective owners. For the most up-to-date listing of EMC product names, see EMC Corporation Trademarks on EMC.com. EMC XtremIO Workload Consolidation and Copy Management Part Number H14673 2 EMC XtremIO Workload Consolidation and Copy Management
Contents Contents Executive summary... 4 Solution architecture and components... 7 Solution design and configuration... 12 Performance and scalability testing... 20 Conclusion... 47 References... 48 Appendix... 49 EMC XtremIO Workload Consolidation and Copy Management 3
Executive summary Executive summary Business case Database management systems (DBMSs) such as Microsoft SQL Server are used to support business-critical applications. To deliver fast response times across the range of applications, SQL Server databases require storage designed for both lowlatency transactional I/O and high-throughput analytic workloads. Virtualization supports greater consolidation of different types of database workloads, enabling both online transaction processing (OLTP) and online analytical processing (OLAP) workloads to share the same servers and storage. The EMC XtremIO all-flash array is designed to perform in demanding virtualized environments and effectively addresses the challenges associated with virtualizing I/O-intensive database workloads. XtremIO delivers very high and consistent performance for random I/O, consistent ultra-low latency, and the best cost-perdatabase economics. This applies equally to OLTP and OLAP workloads, and to consolidated mixed workloads on a common XtremIO storage array. Solution overview This solution provides a highly available and scalable architecture for consolidated SQL Server 2012 and 2014 workloads deployed in a VMware vsphere virtualized environment with XtremIO all-flash storage. The virtualized transactional and decision-support databases are consolidated on the same physical hosts and storage array. VMware vsphere High Availability (HA) provides failover protection against hardware and OS outages. Microsoft SQL Server AlwaysOn Availability Groups (AlwaysOn AG) provides database high availability and disaster recovery. Data protection and availability are enhanced and simplified by using XtremIO Virtual Copy (XVC) technology to create instant, high performance copies of the databases. EMC AppSync copy management software automates copy creation and enables near-instant data recovery. XVC also enables highly effective business intelligence (BI) reporting, realtime analytics, and test and development (DevOps) with no performance impact to the production volumes. Through a series of use cases and test scenarios, the solution demonstrates how XtremIO enhances the capabilities of SQL Server database-dependent environments in terms of performance, data protection, data reduction, data-at-rest encryption (DARE), simplified deployment, and database repurposing. Key results The solution demonstrates: Achieve maximum array performance with XtremIO greatly simplified LUN provisioning, using standardized sizes for ease of deployment and management, and without the need to specify disk groups, RAID configuration, SQL Server object placement, or free space schemes. Superior cost-to-performance ratio using XtremIO Virtual Copies of SQL Server instances for DevOps and QA, in comparison to traditional copy management methods. 4 EMC XtremIO Workload Consolidation and Copy Management
Executive summary EMC AppSync automation and management of XtremIO Virtual Copies can significantly accelerate AlwaysOn AG secondary replica creation, in comparison to SQL Server native backup and restore. Virtual copies of production databases can be created off the secondary replica for downstream operations such as development and testing. Outstanding transactional performance achieved with realistic OLTP workloads up to 300,000 IOPS in this configuration, while maintaining 1 ms to 2 ms host latencies. This greatly exceeds the industry best practices recommendation for storage subsystem response times. No performance impact when consolidating vastly different random OLTP (8K blocks) and sequential OLAP (64K to 128K blocks) workloads on the same XtremIO array. XtremIO arrays spread workload demand evenly across all storage controllers and disk drives for consistent performance and maximum disk lifetime. SQL Server indirect checkpoints produce consistently higher TPS and generate more write I/O activity than the automatic checkpoints for OLTP workloads. The XtremIO array delivered average sub-millisecond latency across all tests for both indirect and automatic checkpoints. SQL Server reached full cache utilization of 150 GB in less than 4 minutes due to the extremely low latency of the XtremIO all flash volumes. SQL Server Transparent Database Encryption (TDE) decreased OLTP performance by 5 percent and OLAP performance by 30 percent in comparison to XtremIO Data at Rest Encryption (DARE). Implementing TDE also results in additional capacity utilization due to encryption of data prior to being written to the array. All configurations of OLTP, OLAP, and AlwaysOn AG copies benefitted from either XtremIO compression or XtremIO deduplication or both. Document purpose Audience This white paper describes the architecture and key components of the solution and demonstrates the operational advantages of virtualized SQL Server databases deployed on XtremIO. The paper outlines how the solution simplifies configuration and, through a series of use cases, demonstrates how the solution enhances the capabilities and performance of SQL Server database environments. The white paper is intended for SQL Server database administrators, VMware administrators, storage administrators, IT architects, and technical managers who are responsible for designing, creating, and managing SQL Server databases, infrastructure, and data centers. EMC XtremIO Workload Consolidation and Copy Management 5
Executive summary Terminology Table 1 provides definitions for some of the terms used in this white paper. Table 1. Terminology Term Asynchronous commit mode Availability database Availability group Availability replica BW OLTP OLAP Synchronous commit mode VMDK XVC Definition In AlwaysOn AG, an availability mode under which changes sent an availability replica do not have to be written to disk for transactions to complete on the primary database. In AlwaysOn AG, a database that belongs to an availability group. For each availability database, the availability group maintains a single read-write copy (primary database) and one to eight read-only copies (secondary databases). In AlwaysOn AG, a container for a set of databases (availability databases) that fail over together. In AlwaysOn AG, an instance of an availability group that is hosted by a specific SQL Server and contains a copy of each availability database in the availability group. An abbreviation for bandwidth used in diagrams in this white paper. Online transaction processing. Transaction-oriented processes such as data entry and retrieval transaction processing. Online analytical processing. Analytics-oriented processes such as reporting, self-service BI, and data mining. In AlwaysOn AG, an availability mode under which changes sent to an availability replica must be written to disk for transactions to complete on the primary database. Virtual Machine Disk. A file format for virtual disks to be used in virtual machines. XtremIO Virtual Copy (formerly XtremIO snapshot). In-memory, writeable replica. XVC technology abstracts copy operations as unique in-memory metadata operations with no impact on any back-end resources. We value your feedback! EMC and the authors of this document welcome your feedback on the solution and the solution documentation. Contact EMC.Solution.Feedback@emc.com with your comments. Authors: Anthony O Grady, Eyal Sharon, Judith Cuppage. 6 EMC XtremIO Workload Consolidation and Copy Management
Solution architecture and components Solution architecture and components This solution provides an optimal cost-to-performance ratio for SQL Server missioncritical application environments. The SQL Server 2012 and 2014 databases are deployed on virtualized SQL Server instances on an XtremIO storage array. The virtualized DevOps SQL Server instances in the environment access XtremIO copies of the production database for testing and development purposes. XtremIO integrates with AppSync to provide database-aware copy management. Key solution components The solution includes the following key technology components: EMC XtremIO all-flash array EMC Virtual Storage Integrator (VSI) VMware vsphere and VMware vcenter Server 6.0 Microsoft SQL Server EMC AppSync copy management software EMC XtremIO The EMC XtremIO storage array is an all-flash system that uses flash storage to deliver value across the following main dimensions: Scalability A single X-Brick is the building block of the XtremIO scale-out architecture. You can cluster up to eight X-Bricks together to provide increased performance and capacity, as shown in Figure 1. Figure 1. XtremIO all-flash array family The XtremIO array s multi-controller, n-way active architecture means that performance scales linearly with capacity. Two X-Bricks supply twice the IOPS of the single X-Brick configuration, four X-Bricks supply four times the IOPS of the single X-Brick configuration, and so on. Latency remains consistently low as the system scales out. EMC XtremIO Workload Consolidation and Copy Management 7
Solution architecture and components Performance Regardless of how busy the system is, and regardless of storage capacity utilization, latency and throughput remain consistent, predictable, and constant. Latency within the array for an I/O request is typically much less than one millisecond (ms). Efficiency XtremIO supports high-performance and space-efficient copies, inline data reduction (including inline deduplication and data compression), thin provisioning, DARE, and full integration with VMware vsphere Storage APIs for Array Integration (VAAI) with support for FC and iscsi protocols. Simplicity Provisioning storage with XtremIO is as simple as deciding the size of the LUN or LUNs that you want to create and then mapping the LUNs to a host. There is no need to select the RAID type, create a RAID group, or decide whether to enable thin provisioning, deduplication, or any other data service. These functions are built into XtremIO. Data protection XtremIO uses a proprietary flash-optimized data protection algorithm, XtremIO Data Protection (XDP), which protects data while enabling performance that is superior to any existing RAID algorithms. Optimizations in XDP also result in fewer writes to flash media for data protection purposes. For more information about XtremIO, visit www.emc.com/storage/xtremio/. EMC Virtual Storage Integrator EMC Virtual Storage Integrator (VSI) is a plugin for VMware vcenter Server that integrates EMC storage management with vcenter Server. VSI provides VMware administrators with full visibility into EMC storage directly from vcenter, and enables server administrators to easily handle storage-related tasks using the familiar vcenter Server interface. In this solution, we used VSI to streamline and simplify the task of configuring best practice settings. For more information about VSI, refer to the EMC VSI for VMware vsphere Web Client Product Guide. VMware vsphere This solution demonstrates how XtremIO offers efficient enterprise storage with VMware vsphere cloud infrastructures. vsphere provides complete and robust virtualization, enabling SQL Server instances to be virtualized on fully functional virtual machines that run isolated and encapsulated operating systems and applications. In this solution, we configured the ESXi servers as a vsphere High Availability (HA) cluster to ensure failover protection against hardware and operating system outages within the virtualized environment. Microsoft SQL Server The SQL Server DBMS is capable of handling enterprise-level workloads. This solution uses the OLAP data warehousing (DW), BI, and operational OLTP features of the product. SQL Server also provides several high-availability options for databases. This solution uses AlwaysOn Failover Cluster Instances (FCI) and AlwaysOn AG. 8 EMC XtremIO Workload Consolidation and Copy Management
Solution architecture and components EMC AppSync AppSync offers simple, SLA-driven, self-service application protection with tiered protection options and proven recoverability. AppSync support for XtremIO enables orchestration and automation of the creation, mounting, and recovery of multiple SQL Server database-consistent copies. Service plans that match the specific SLA requirements of individual databases control these operations. AppSync supports the following features for SQL Server: AlwaysOn AG Dynamic discovery of user databases during a service plan run SQL Server databases on physical hosts, raw device mapping (RDM) in physical compatibility mode, and virtual disks on virtual hosts Note: AppSync does not support RDM disks in virtual mode. Data protection of stand-alone and clustered production SQL Server instances Mounting to any non-clustered instance of SQL Server (physical or virtual) and mounting as files to any Windows host Mounting with recovery, no recovery, or standby on non-clustered instances For more information about AppSync, visit www.emc.com/storage/data-replication/appsync.htm. Solution architecture As shown in Figure 2, the solution architecture includes the following: Storage layer Two XtremIO X-Bricks clustered as a single logical storage system. SQL Server database layer Two clustered instances (Instance1 and Instance2), and a single standalone instance (Instance3), of SQL Server 2014, with 10 OLTP databases per instance. A SQL Server AlwaysOn AG instance (Instance 2, Instance4, and Instance5) configured using XVC copies. One clustered instance (Instance6) of SQL Server 2012 with a 4 TB OLAP database. XVC copies of the SQL Server databases for backup and repurposing, with both first-generation master copies and second-generation copies used for DevOps. The copies can be mounted to any of the mount hosts at any time, as necessary. Application Layer The application workload tools consist of separate OLTP and OLAP clients. vcenter Server and the EMC Virtual Storage Integrator plug-in provide central management and simple provisioning. AppSync provides database-aware copy management. The solution has a dependency on Microsoft Active Directory for enforcing security and authenticating and authorizing users. EMC XtremIO Workload Consolidation and Copy Management 9
Solution architecture and components Network layer 108 GB/s of active bandwidth with SAN switches that support virtualized data centers and enterprise clouds. Physical servers and virtualization layer Four rack-mounted servers that enable a high-performing, consolidated, virtualized SQL Server infrastructure for deployment flexibility without the need to modify the application. The ESXi servers are configured as a VMware vsphere High Availability (HA) cluster. Figure 2. Logical architecture of the solution 10 EMC XtremIO Workload Consolidation and Copy Management
Solution architecture and components Hardware resources Table 2 lists the hardware resources used in the solution. Table 2. Hardware resources Hardware Quantity Configuration Storage array 1 EMC XtremIO with two clustered X-Bricks with a total of 30.4 TB of usable physical capacity. Servers 4 40 Intel E7 2.9 GHz processor cores (80 logical) with: 512 GB of RAM 2 x 1 Gb quad Ethernet (GbE) NIC 2 x 10 GbE NICs 2 x 8 GB FC dual-port HBAs LAN switches 2 10 GbE, 32-port non-blocking LAN switch. SAN switches 2 EMC Connectrix DS-6510B enterprise-class SAN switch. Software resources Table 3 lists the software resources used in this solution. Table 3. Software resources Software Version Notes XtremIO 4.0.1 All-flash storage. VMware vsphere 6.0 Hypervisor that hosts: Four enterprise-class production virtual machines Three clustered and one standalone SQL Server virtual machines Each virtual machine is configured with 40 vcpus and 150 GB of RAM. VMware vcenter Server 6.0 vsphere management. Microsoft Windows 2012 R2 SP1 OS for database servers. Microsoft SQL Server 2012 Microsoft SQL Server 2014 Enterprise Edition SP2 Enterprise Edition SP1 Database software. Database software. EMC AppSync 2.2.2.0 SQL Server SLA-driven copy management tool, which is integrated with the Volume Shadow Copy Service (VSS). EMC PowerPath/VE 6.0 EMC storage multipath management. EMC Virtual Storage Integrator Industry-standard OLTP and OLAP workload toolkits 6.6 VSI provides the ability to view, provision, and manage EMC block and file storage in a Windows environment. n/a These toolkits simulate OLTP and OLAP workloads respectively. EMC XtremIO Workload Consolidation and Copy Management 11
Solution design and configuration Solution design and configuration XtremIO storage design overview With XtremIO, the performance of your SQL Server workloads is always consistent and predictable, regardless of LUN size, access patterns (sequential or random), and locality of reference database administrators (DBAs) do not need to worry about hot spots on the array. Because storage configuration is set at the factory, you do not need to design or configure disk groups or RAID types. File separation is also unnecessary. Because of the consistent performance of XtremIO across all workloads, disruptive tempdb workloads can co-exist in the same LUN with their write-intensive transaction logs and still provide excellent performance. In addition, with built-in thin provisioning, storage is allocated only when it is needed. This allows DBAs to create larger LUNs to accommodate future or unexpected database growth without wasting any physical space on storage. Metadata operations, such as inline data reduction, thin provisioning allocations, and internal array copy operations, are conducted entirely in memory without affecting I/O operations. Database storage design considerations Uncertainty in capacity planning models requires that you plan for unpredictable data growth to meet changing business needs. Ensuring free space for growth at all levels of the storage stack (from data file to LUN) and not locking out valuable storage capacity ahead of time is vital. EMC and SQL Server traditional best practices recommend that you configure SQL Server data file sizes to be 10 percent to 20 percent larger than the current or intended database size. This configuration requires free space at the NTFS volume level and results in the underlying storage space being locked out until the space is needed. A maintenance window and manual intervention is required if the NTFS volume needs expansion. It is difficult to balance how much free disk space to allocate for the database at the design stage free space that will not have an immediate use against the amount of free space that needs to be readily available for near future growth. The cost and management complexity of free space is compounded multiple times in environments with many SQL Server instances and large numbers of database and log files. Figure 3 shows an example of a 1 TB database, which requires at least 1.58 TB of allocated storage space to adhere to traditional storage design best practices. This represents about a 58 percent waste of physical storage allocation. Figure 3 also shows how, on XtremIO storage, the database can easily use significantly less physical storage allocation and still satisfy the logical free space requirement for storage planning. The example shows an overall 2:1 data reduction rate on XtremIO for a typical OLTP or OLAP database environment. 12 EMC XtremIO Workload Consolidation and Copy Management
Solution design and configuration Figure 3. XtremIO storage capacity planning XtremIO uses thin provisioning, deduplication, and compression to achieve this reduction. XtremIO thin provisioning prevents large volume allocations from wasting physical storage in advance of need, while still providing room for growth when required. Thin provisioning also eliminates operational complexities DBAs can allocate, from the start, as much LUN space, virtual file system space and, therefore, NTFS volume space as required. Solution storage design For this solution, we deployed XtremIO as a cluster of two X-Bricks (20 TB each) with an available physical capacity of 30.5 TB, as shown in Figure 4. Figure 4. XtremIO Management Application storage panel XtremIO processes both random and sequential I/O generated from a database in an equally balanced way across the array. This simplifies the storage design for SQL Server databases compared to traditional provisioning techniques. EMC XtremIO Workload Consolidation and Copy Management 13
Solution design and configuration For the solution, we standardized the volume size for ease of deployment, as shown in Table 4. Table 4. Database volume template Volume Volume size Volume type OLTP databases OS 120 GB VMDK SQL Server installation and systems databases 120 GB VMDK SQL Server data and log 2 TB Raw device mapping (RDM) or VMDK Tempdb 2 TB RDM or VMDK OLAP databases OS 120 GB VMDK SQL Server installation and systems databases 120 GB VMDK SQL Server data 2 TB RDM or VMDK SQL Server log 500 GB RDM or VMDK Tempdb 2 TB RDM or VMDK Note: The performance and availability of RDM and VMDK volumes are similar, so either choice is reasonable depending on individual design requirements. Certain technologies, such as Windows Server Failover Clustering (WSFC), require RDMs when running in virtual machine clustering (to support SCSI-3 reservations). Solution database design We created the following virtualized SQL Server instances and databases on a vsphere HA cluster: Five SQL Server 2014 production instances with transactional (OLTP) databases One SQL Server 2012 production instance with an analytical (OLAP) database As shown in Table 4, we used different database volumes to store the relevant database files. In general, a single database LUN is sufficient for most OLTP databases that require high disk performance. OLAP databases might require up to eight LUNs to provide more disk queues for data files, and a single LUN for the log file. Note: With XtremIO, putting all database files for a single SQL Server database into one LUN easily provides over 20,000 IOPS for OLTP workloads, with sub-millisecond performance. For OLAP databases, evenly distribute the data files across eight XtremIO data volumes. 14 EMC XtremIO Workload Consolidation and Copy Management
Database profiles Table 5 details the OLTP and OLAP database profiles for the solution. Solution design and configuration Table 5. OLTP and OLAP database profiles Item Database size SQL Server databases Memory for SQL Server Workload profiles Average data block sizes Database file layout Checkpoint configuration max degree of parallelism (MAXDOP) configuration Details 250 GB 30 x 250 GB OLTP 20 x 250 GB OLTP mount 1 x 4 TB OLAP 1 x 4 TB OLAP mount 150 GB to 320 GB OLTP workload simulated by an industry-standard OLTP workload toolkit OLTP read/write ratio of 90/10, 70/30, 60/40 OLAP workload simulated by an industry-standard OLAP workload toolkit OLAP 100% reads OLTP reads: mainly 8K index seeks OLTP log writes: 4K to 60K (mainly ~4K) OLTP Background writer: 8K or 32K (mainly 8K) OLAP reads: 64K or 128K OLTP: 8 data files, 1 log file OLTP tempdb: 8 data files, 1 log file OLAP: 64 data files, 1 log file OLAP tempdb: 32 data files, 1 log file OLTP: Indirect checkpoint, 60-second recovery interval OLAP: Default configuration (Automatic checkpoint) OLTP: MAXDOP 1 OLAP: various MAXDOP settings Database LUN design Table 6, Table 7, and Table 8 provide details of the database LUN design for the solution. Table 6. LUN design details for the OLTP databases Item Database name Database and log file size Production OLTP AlwaysOn AG mounts OLTP Instance 1 Instance 2 Instance 3 Instance 4 Instance 5 DB_10 to DB_19 Tempdb DB_20 to DB_29 Tempdb DB_30 to DB_39 Tempdb DB_30s to DB_39s Tempdb DB_30ss to DB_39ss Tempdb 250 GB 250 GB 250 GB 250 GB 250 GB 250 GB 250 GB 250 GB 250 GB 250 GB LUN size 10 x 2 TB 1 x 2 TB 10 x 2 TB 1 x 2 TB 10 x 2 TB 1 x 2 TB 10 x 2 TB 1 x 2 TB 10 x 2 TB 1 x 2 TB EMC XtremIO Workload Consolidation and Copy Management 15
Solution design and configuration Table 7. LUN design details for the OLAP database Item Production OLAP Instance 6 Database name DB_DW tempdb Database and log file size 4 TB 1 TB LUN size 8 x 2 TB 4 x 2 TB Log LUN size 1 x 2 TB 1 x 2 TB Table 8. Total sizes for OLTP and OLAP databases Database Total data and log size Total LUN size Production AlwaysOn AG mounts 11.5 TB (excluding tempdb) 13.25 TB (including tempdb) 5 TB (excluding tempdb) 5.5 TB (including tempdb) 78 TB (excluding tempdb) 93 TB (including tempdb) 42 TB (excluding tempdb) 44 TB including tempdb) Notes: This database LUN design is based on our test workload. In a production environment, database size, especially log file and tempdb size, can vary depending on the types of transactions and queries that are running on the databases. AppSync copies can be mounted on a SQL Server mount host and enabled for clients to connect. The suffix s in the database name indicates a first-generation copy 1. For example, DB_30s is a first-generation copy of database DB_30 that is mounted on the mount host. The suffix ss in the database name indicates a second-generation copy. For example, DB_30ss is a second-generation copy of database DB_30 taken from DB_30s and mounted on the mount host. Best practice settings for ESXi hosts on XtremIO The VSI plug-in enables VMware administrators to easily set ESXi host parameters to the recommended settings for XtremIO. VSI presents the recommended settings through a GUI wizard, as shown in Figure 5. This greatly simplifies and accelerates the provisioning process. As a best practice, we used the recommended settings when configuring the ESXi hosts for the solution. 1 A first-generation copy is a copy that is taken from a database. A second-generation copy is a copy that is taken from a first-generation copy. 16 EMC XtremIO Workload Consolidation and Copy Management
Solution design and configuration Figure 5. Configuring ESXi host recommended settings for XtremIO with VSI For more information on using VSI, refer to the EMC VSI for VMware vsphere Web Client Product Guide. AppSync copy management For the solution, we used AppSync to create and manage database-consistent XVC copies of the SQL Server databases. We validated AppSync with AlwaysOn AG by seeding, restoring, and repurposing an availability group. This section outlines the AppSync options involved in these tasks. For more information on using AppSync to create and manage copies of SQL Server databases, refer to the EMC AppSync User and Administration Guide. Seeding an AlwaysOn AG availability group The AlwaysOn AG feature supports a failover environment for a discrete set of user databases (availability databases) that fail over as a group. An availability group supports a set of primary databases and up to four (SQL Server 2012) or eight (SQL Server 2014) sets of corresponding secondary databases. To add databases to an availability group, you must restore backups of the primary databases to the server instance that hosts the secondary replica. This is a time consuming process that requires multiple steps for multiple databases. With AppSync and XtremIO, however, the process is consolidated into a simple streamlined operation. EMC XtremIO Workload Consolidation and Copy Management 17
Solution design and configuration To validate database seeding, we protected 10 availability databases as a group on the primary instance, during a maintenance window. We then restored all the databases in a single operation by using the Mount Copy of SQL Server wizard in AppSync, as follows: 1. Select the first database copy in the availability group and select Mount. 2. In the Mount Additional Copies window, select the other nine databases, as shown in Figure 6. 3. Follow the standard AppSync procedures to mount and recover the databases. Figure 6. Restoring 10 databases for an availability replica in a single operation Restoring a SQL Server OLAP database after a failed maintenance operation Subscribing a database to an AppSync service plan indicates that you want to protect the database by scheduling reoccurring copy creation. As the service plan runs, copies of the database are created and stored at the required intervals, facilitating point-in-time recovery. To validate database recovery, we simulated a failed maintenance operation on a 4 TB OLAP database by dropping a table. We then used AppSync to select the most recent copy from the service plan and quickly restored the database to the state that it was in before the table deletion. Making multiple repurposed copies An availability replica is held on an instance of SQL Server and contains a copy of all availability databases in an availability group. Availability replicas support two availability modes: asynchronous commit mode and synchronous commit mode. The asynchronous commit mode enables agile, near realtime copies of the database to be taken at any time without affecting production performance. To validate AppSync with this mode, we used an asynchronous replica as a source for creating multiple repurposed copies of the databases, making first- or second-generation copies of three to five databases at one time. You must use the SQL Server copy-only option when backing up from an availability replica. In AppSync, select the Snap and Copy options when creating the copy, as shown in Figure 7. 18 EMC XtremIO Workload Consolidation and Copy Management
Solution design and configuration Figure 7. Creating a first-generation copy with AppSync EMC XtremIO Workload Consolidation and Copy Management 19
Performance and scalability testing Performance and scalability testing Overview The performance and scalability tests we performed for this solution highlight how XtremIO easily services vastly different and competing enterprise workloads while all elements, including storage, stay within the green zone, which is a state of utilization and latency that is healthy and sustainable for production workloads. For the tests, we: Generated OLTP workloads using an industry-standard OLTP workload toolkit application that produces realworld transaction-oriented workloads Generated OLAP workloads using an industry-standard OLAP workload toolkit application that produces realworld data analytics workloads Ran the workloads on a dual-brick XtremIO system that we configured according to best practices Collected system I/O performance metrics, including IOPS, transactions per second (TPS), and latency, at the server (database) and storage levels Figure 8 summarizes the performance profile for all the performance tests. Figure 8. XtremIO performance profile for all performance tests 20 EMC XtremIO Workload Consolidation and Copy Management
Notes on performance results Performance and scalability testing Test results are highly dependent on workload, specific application requirements, and system design and implementation. Relative system performance will vary because of these and other factors. Therefore, you should not use the solution workloads as a substitute for a specific customer application benchmark for critical capacity-planning and product-evaluation decisions. All performance data contained in this white paper were obtained in a rigorously controlled environment. Results obtained in other operating environments might vary significantly. EMC does not warrant or represent that a user can or will achieve similar performance. Test objectives The overall test objectives were to demonstrate: Performance and scale In a series of tests, we measured SQL Server 2014 overall performance and scalability when servicing common OLTP workloads with varying I/O profiles. Baseline OLTP workload We created a baseline OLTP workload to simulate a typical production environment and demonstrate that this environment delivers performance and scalability for OLTP workloads. We used this workload as the basis for the subsequent tests. SQL Server mixed workloads sustainability XtremIO can deliver high throughput and minimal latency for OLTP and OLAP mixed workloads without the need for workload separation or Quality of Service (QoS). Data reduction One of the most impressive capabilities of XtremIO storage is its inline data reduction features. We addressed several aspects of data reduction as it applies to SQL Server environments. Data-at-rest encryption Business requirements to strengthen security are becoming more and more common. To address these requirements, XtremIO version 4 enables DARE by default. We compared XtremIO DARE to the native SQL Server Transparent Data Encryption (TDE) technology for capacity requirements and performance. Support for SQL Server AlwaysOn FCI and AlwaysOn AG on vsphere 6.0 We validated XtremIO support for environments that require the protection of SQL Server AlwaysOn FCI and AlwaysOn AG. Data repurposing with XVC and AppSync We used AppSync to create multiple copies of the production databases and measured the performance impact of AppSync operations. We also measured the effect of multiple copies on the overall data reduction rate. EMC XtremIO Workload Consolidation and Copy Management 21
Performance and scalability testing Test scenarios We tested the following use cases: OLTP linear performance and scalability analysis, including: SQL Server checkpoint impact on variable OLTP workloads Baseline SQL Server OLTP workload Mixed OLTP and OLAP workload performance analysis, including: Performance effect of OLAP query spill operations DevOps copy management performance analysis XtremIO DARE and SQL Server TDE comparison Data reduction analysis, including: SQL Server AlwaysOn AG and AppSync copy management XtremIO data reduction with SQL Server row, page, and columnstore compression OLTP linear performance and scalability analysis The objective of this test was to measure SQL Server 2014 overall performance and scalability while servicing common OLTP workloads with varying I/O profiles. The test simulated a wide spectrum of high-volume, online transactional workloads that are seen in financial services systems, online gaming solutions, e-commerce solutions, and so on. The main metrics we measured were read and write I/O latencies, aggregated throughput in IOPS, and SQL Server TPS. The test also demonstrated how an XtremIO system can accommodate growing database workloads and continue to provide stable performance. In addition, we examined the effect of the SQL Server checkpoint on OLTP workloads, with variable read/write ratios, executed against one of the test databases. This test is described separately at the end of the section. Test methodology We used the OLTP workload toolkit to generate an OLTP workload to drive high physical random I/O to the databases. We configured the toolkit so each database had a fixed number of concurrent users. All the databases ran the same set of OLTP queries. Controlling the number of concurrent users and databases ensured that we generated a specific level of IOPS. Test procedure 1. We ran an OLTP workload for the first database and recorded the system performance after the workload stabilized. 2. We added a workload to four additional databases while the previous workload was still running and recorded system performance after the workload stabilized. 3. We continued adding workloads and recording system performance in increments of five databases until all databases were running with a stabilized workload. 22 EMC XtremIO Workload Consolidation and Copy Management
Performance and scalability testing Table 9 shows the test load sequence; all workloads had a read/write ratio of 90:10. For details about the database profile and configuration, refer to Table 5 on page15. Table 9. Test workload sequence Workload sequence Database name (all 250 GB databases) Total no. of databases Workload (no. of users) 1 DB_10 1 9 2 DB_10 to DB_14 5 45 3 DB_10 to DB_19 10 90 4 DB_10 to DB_24 15 135 5 DB_10 to DB_29 20 180 6 DB_10 to DB_34 25 225 7 DB_10 to DB_39 30 270 8 DB_10 to DB_39, DB_30s to DB_34s 35 315 9 DB_10 to DB_39, DB_30s to DB_39s 40 360 10 DB_10 to DB_39, DB_30s to DB_44ss 45 405 Test results Overall, the average latency remained low for the XtremIO array, while the added database workloads generated more I/O. The entire system generated over 90,000 TPS, with an average of 300,000 IOPS when all database workloads were added and stabilized, as shown in Figure 9. The XtremIO array latency remained at approximately 1 ms and the host s average disk latency ranged from less than 1 ms to 2 ms. Figure 9. SQL Server and XtremIO scalability test EMC XtremIO Workload Consolidation and Copy Management 23
Performance and scalability testing XtremIO system performance XtremIO provided extremely high IOPS and throughput with very low latency and a high overall SQL Server transaction rate, as shown in Figure 10. Figure 10. XtremIO performance with full OLTP workload XtremIO SSD and XDP linear scaling XtremIO N-way, active/active, scale-out architecture linearly scales capacity and performance, creates extremely high IOPS or throughput, and maintains extremely low latency. The XtremIO Management Server (XMS) GUI reporting feature facilitates the capture of realtime performance data. We set up Resource, IOPS, and Latency reports and observed them while the OLTP workload was running. As shown in the Figure 11, regardless of the number or source of the database workload IOPS 1, XtremIO balances I/O processing evenly across storage processors 2 and SSDs 3. 24 EMC XtremIO Workload Consolidation and Copy Management
Performance and scalability testing Figure 11. XtremIO SSD and XDP linear scaling SQL Server checkpoint impact on variable OLTP workloads The objective of this test was to measure the impact of the SQL Server database checkpoint on variable OLTP workloads. Transactional modifications to data pages are performed in memory and periodically written to disk. A data page might be modified multiple times before it is written to disk. A combination of the workload profile and the checkpoint type used determines the frequency and intensity of checkpoint write IOPS: Automatic checkpoint Executes less frequently than other checkpoint types, but under a write-heavy workload might cause an I/O spike and affect transaction processing. This is the default checkpoint, and is used for OLAP workloads in this solution (see Table 5 on page 15). Indirect checkpoint Can offer a more consistent I/O pattern, but can also increase the total percentage of write IOPS. This is the checkpoint type used for OLTP workloads in this solution (see Table 5 on page 15). EMC XtremIO Workload Consolidation and Copy Management 25
Performance and scalability testing For this test scenario, we tested both checkpoint types on a single OLTP database DB_20 (250 GB) while varying the read/write ratio of the workload. As shown in Figure 12, we completed three tests, increasing the percentage of write I/Os for the second and third tests. For all three tests, the indirect checkpoint delivered consistent latency and higher TPS than the automatic checkpoint, but with a greater percentage of write I/O. The XtremIO array delivered sub-millisecond latency across all tests. Figure 12. OLTP database performance with automatic and indirect checkpoints Baseline SQL Server OLTP workload The objective of this test was to demonstrate that performance and scalability for typical OLTP workloads on XtremIO can be achieved using a highly simplified storage layout while still delivering a highly responsive solution. The layout uses the minimum number of required LUNs that is, one LUN for each database. Database data and log files can be consolidated on the same LUN to simplify design. Table 6 on page 15 outlines the storage layout. Note: The OLTP workload used in this test served as a baseline for the remaining tests documented in this paper. Test methodology We used the OLTP workload toolkit to generate an OLTP workload to drive physical random I/O to the databases. We configured the toolkit so each database had a fixed number of concurrent users. All the databases ran the same set of OLTP queries. Controlling the number of concurrent users and databases ensured that we generated a specific level of IOPS. 26 EMC XtremIO Workload Consolidation and Copy Management
Test procedure Performance and scalability testing We ran an OLTP workload for 30 production databases and recorded the system performance for one hour after the workload stabilized. Test results With a simplified storage layout, the XtremIO array can service all the OLTP workloads while maintaining average sub-millisecond latency for all databases. As shown in Figure 13, the average latency variance between all databases was just 60 microseconds. Figure 13. I/O profile of baseline OLTP workload Figure 14 charts the execution count, the logical reads and writes, and the physical reads, for all procedures executed against one of the production databases in the one-hour period. The data was recorded by and analyzed from the SQL Server sys.dm_exec_procedure_stats dynamic management view (DMV). EMC XtremIO Workload Consolidation and Copy Management 27
Performance and scalability testing Figure 14. OLTP production database page reads and writes: logical versus physical Note: To process an OLTP workload, SQL Server reads and writes data pages. A logical read refers to an SQL Server read of a data page. A physical read refers to retrieval of the data page from disk because the page is not in the buffer pool (an area of memory reserved for SQL Server data pages). A logical write refers to an SQL modification to a data page. On NUMA hardware, modifications to data pages are eventually written to disk by the lazy writer during a checkpoint. The SQL Server OLTP database workload used for this solution produced an I/O pattern of predominantly 8K reads for seeks and 8K lazy writer commits. However, SQL Server transaction performance is a function of read latency for scans, seeks, and lookups, write latency for lazy writer commits, and writes to the transaction log. Table 10 shows the Access Methods, Buffer Manager, and Databases activity for the test workload. This activity can produce a varied I/O pattern and block size. Table 10. Access methods and Buffer Manager activity for OLTP workload Counter name Value SQL Server: Access Methods Full Scans/sec 70.554 Index Searches/sec 2,301,413.787 Range Scans/sec 11,282.115 Workfiles Created/sec 3.167 Worktables Created/sec 1.192 28 EMC XtremIO Workload Consolidation and Copy Management
Performance and scalability testing Counter name Value SQL Server: Buffer Manager Background writer pages/sec 152.762 Lazy writes/sec 1,500.088 Page lookups/sec 4,842,695.642 Page Reads/sec 23,694.463 Page Writes/sec 1,652.856 Readahead pages /sec 3,754.080 SQL Server: Databases Log Bytes Flushed/sec 1,098,465.893 Log Flushes/sec 181.955 To maximise SQL Server transaction processing, a well-designed I/O subsystem needs to perform well with this varied I/O pattern and block size. With XtremIO, no additional design considerations are required to satisfy this requirement. For the test workload, the array responded to all request sizes with sub-millisecond latency. SQL Server start-up performance The test OLTP workload had an I/O pattern of primarily 8K reads for page lookups. One exception to this pattern occurs during buffer cache ramp-up 2, when SQL Server transforms 8K requests into aligned 64K requests. In the test environment, the 10 OLTP databases on each OLTP instance share a 150 GB buffer cache. We analyzed the performance data to determine the ramp-up time for the SQL Server buffer cache on XtremIO. Figure 15 shows that it took just 3 mins and 38 secs for SQL Server to reach its memory target. After this initial period, the database TPS permanently stabilizes. 2 Buffer cache ramp-up refers to the time it takes to fill the buffer cache up to its memory target after SQL Server start-up or a restart. EMC XtremIO Workload Consolidation and Copy Management 29
Performance and scalability testing Figure 15. SQL Server ramp-up time on XtremIO Figure 16 shows activity in MB/s and demonstrates that the XtremIO array responds to both the ramp-up 64K requests and the subsequent 8K requests with submillisecond latency. Figure 16. XtremIO response to 64K ramp-up and 8K OLTP workload processing requests 30 EMC XtremIO Workload Consolidation and Copy Management
Performance and scalability testing Mixed OLTP and OLAP workload performance analysis To guarantee predictable performance for consolidated workloads, administrators typically separate the IT resources allocated to competing workloads like OLTP and OLAP. They might also implement QoS mechanisms to maintain the agreed SLAs for each workload. The objective of this test was to demonstrate that, with XtremIO, multiple competing and completely different workloads can run simultaneously on the same array, leveraging the same pool of storage devices, yet provide high throughput with minimal latencies. We performed an additional test to review the performance effect of OLAP query spill operations. The array responded to simultaneous tempdb read and write requests with an average response time of less than 700 microseconds. See Appendix > SQL Server tempdb and OLAP queries for details. Test methodology We used the OLTP workload toolkit to generate an OLTP workload against our 30 production databases. The workload pattern was identical to that used in the baseline OLTP test (see Baseline SQL Server OLTP workload). We used the OLAP workload toolkit to generate an OLAP workload against the SQL Server 2012 4 TB Data Warehouse (DW) database. We initially configured the OLAP database as a rowstore without compression. During the test procedures, we implemented in-memory columnstore indexing compression. Test procedure 1. As an OLTP-only baseline, we used the production workload performance metrics obtained in the baseline OLTP test (see Baseline SQL Server OLTP workload). 2. To gather baseline performance for the rowstore OLAP-only workload, we stopped the production workload and ran the OLAP workload. 3. With the production OLTP workload running again, we introduced the rowstore OLAP workload and gathered performance metrics. We analyzed the data obtained to ensure that baseline OLTP production performance was still achievable. 4. We added columnstore indexing to the OLAP DW database. 5. To gather baseline performance for the columnstore OLAP-only workload, we stopped the production workload and ran the OLAP workload. 6. With the production OLTP workload running again, we introduced the columnstore OLAP workload and gathered performance metrics. We analyzed the data obtained to ensure baseline OLTP production performance was still achievable. Test results Overall, the impact of introducing OLAP workloads into an XtremIO array with an existing production OLTP workload was less than 2 percent. High bandwidth OLAP scans on the same array had a minimal impact on OLTP latencies and throughput. For EMC XtremIO Workload Consolidation and Copy Management 31
Performance and scalability testing all workload tests, the XtremIO array continued to maintain an overall average latency of less than 1 ms. Host performance results: OLTP workloads As shown in Figure 17, when expressed in host-side IOPS and TPS, the impact on the production OLTP workload was less than 2 percent when either the rowstore or the columnstore OLAP workloads were introduced on the same XtremIO array. Figure 17. Sustaining OLTP workload performance with mixed OLAP workloads Host performance results: OLAP query processing OLAP consists of a mixture of long running queries that interrogate large DW data sets and shorter running queries that scan ranges of data. The queries are usually characterized by how long they take to run. We took performance data collected from the SQL Server sys.dm_exec_query_stats DMV and aggregated the workload reads for both the rowstore and columnstore tests. As shown in Table 11, introducing columnstore indexing reduced the overall volume of both the physical and logical processing required to satisfy the same set of OLAP DW queries. Table 11. Aggregated workload processing for both rowstore and columnstore tests Workload Type Logical Reads Physical Reads OLAP Columnstore 24,383,263 12,216,239 OLAP Columnstore + OLTP 24,383,248 12,221,930 OLAP ROWSTORE 336,295,252 336,294,989 OLAP ROWSTORE + OLTP 336,295,252 336,294,989 32 EMC XtremIO Workload Consolidation and Copy Management