Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

Transcription

1 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN This Dell technical white paper describes the tasks to deploy a high IOPS (heavy user), 800-user, virtual desktop environment in a VMware Horizon View VDI infrastructure by leveraging Fluid Cache and Compellent storage array. A Dell Reference Architecture January Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

2 Revisions Date January 2015 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 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

3 Contents Revisions... 2 Executive summary Introduction Objectives Audience Dell Fluid Cache for SAN and VDI Solution architecture Software: Horizon view Horizon view components Virtual desktops Horizon view desktop pools Using linked clones Hypervisor platform: VMware vsphere Hardware: Dell infrastructure Solution configuration Host design considerations Network design considerations Dell Compellent SC8000 storage array configurations vsphere host network configuration Horizon view configuration Windows 7 VM configuration Horizon view test methodology Test objectives Test tools Load generation Monitoring tools Test criteria Storage capacity and I/O latency System utilization at the hypervisor Virtual desktop user experience Test configuration Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

4 6 Test results and analysis Test scenarios Boot storm I/O Login storm and steady state for standard users (LoginVSI Medium) Server host performance Monitoring user experience Standard user test results summary Login storm and steady state for heavy users (LoginVSI Medium + Iometer) Server host performance User experience monitoring Heavy user test results summary Best practices Virtual Desktop Infrastructure Implement roaming profiles and folder redirection Boot and login storm considerations Windows 7 master image for desktop VMs VDI Management infrastructure recommendations Server host Network layer Storage Conclusion A Horizon view solution configuration B vsphere host network configuration B.1 vswitch Management traffic B.2 vswitch - iscsi B.3 vswitch Fluid Cache network B.4 vswitch Additional resources Acknowledgements Feedback Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

5 Executive summary A Virtual Desktop Infrastructure (VDI) deployment can place high storage capacity and performance demands on the storage platform. For example, consolidating large amounts of inexpensive stand-alone desktop storage in to a centralized infrastructure can create tremendous storage capacity demands on centrally managed shared storage used in VDI deployments. Performance demands are determined by the number of I/O operations per second (IOPS) generated by basic desktop client operations such as system boot, logon, and logoff, and by desktop usage operations from different users. Storm events such as simultaneous booting of many desktops, morning logons, and afternoon logoffs by many users at approximately the same time and virus scan can cause I/O requirement variances that place high performance demands on the storage infrastructure. Current VDI solutions in the market can cost-effectively manage desktop virtualization use cases where performance demands are not really demanding. For example, a task worker environment in a call center can generate 5 10 IOPS/VM, or a knowledge worker environment in an office can generate IOPS/VM. Typically, hybrid arrays or all-flash arrays are deployed to accommodate performance needs in these VDI environments. The next frontier for VDI to conquer is the high IOPS use cases such as a software developer organization or an engineering CAD/CAM team. In these use cases, not only the capacity demands are large (repositories for code or design in development), but also performance demands are extremely high (often IOPS/VM). Dell Fluid Cache for SAN an innovative server-side read/write caching solution for workload acceleration can provide an innovative, cost-effective solution for high IOPS type VDI environments. Even though these VDI environments need a lot of storage capacity, the working set is typically relatively small. However, this working set is very I/O intensive more read operations (write operations) during boot storms and more write-operations during steady state. Fluid Cache software can provide extremely high IOPS with minimal latency for these working set VDI data leveraging PCIe SSDs as read/write cache pool in the computational tier, while a Dell Compellent SAN storage array can provide the performance and large capacity needed for the shared storage. This combination fits perfectly for high IOPS VDI environment. This technical white paper demonstrates how a high IOPS, 800-user virtual desktop environment can be deployed in a VMware Horizon View VDI infrastructure leveraging Fluid Cache and Compellent storage array. The test infrastructure also included Dell Networking switches and Dell PowerEdge servers running VMware vsphere 5.5 as the hypervisor. In the test environment, the solution infrastructure successfully hosted 800 desktops with satisfactory performance results across all layers of the stack, including the user layer, hypervisor layer, and storage layer, while delivering approximately 90 IOPS/VM as a sustained steady state load. Fluid Cache performance ensured excellent end-user desktop application response times, as determined by the user-level experience monitoring software, LoginVSI s VSIMax. Details are provided for the storage I/O characteristics about various VDI workload scenarios such as boot and login storms along with performance characteristics throughout the VDI stack. 5 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

6 1 Introduction Desktop virtualization platforms such as VMware Horizon View 6.0 (Horizon View) can provide organizations with significant cost savings, streamlined implementation, and ease of desktop management. In order to achieve these VDI benefits and to ensure optimal user experience, the end-toend infrastructure design and sizing considerations need to be addressed carefully. While VDI workloads for task and knowledge workers are correctly understood by using many cost-effective solutions that are available, the high IOPS, 800-user VDI use cases are addressed less often, because current solutions typically do not meet the stringent performance- and capacity requirements of these use cases in an economically sensible manner. The goal of this technical white paper is to present the results of a series of storage I/O performance tests and provide the optimal end-to-end infrastructure design for high IOPS, 800-user type VDI environments leveraging Dell Fluid Cache for SAN, Dell Compellent SAN storage arrays, Dell PowerEdge servers, and Dell Networking switches. 1.1 Objectives The primary objectives of the tests conducted for this technical white paper are: Develop an optimal end-to-end infrastructure design for a Horizon View and vsphere-based heavy user type VDI solution deployed by using the Fluid Cache, Compellent storage, PowerEdge servers, and Dell Networking switches Determine the performance at every layer of the VDI solution stack under high IOPS workload. For example, desktops generating IOPS/VM at steady state Determine the performance impact of peak I/O activity such as boot and login storms The test infrastructure used for the tests included: VMware Horizon View 6.0 VMware vsphere 5.5 hypervisor Dell PowerEdge R720 servers with Dell Express PCIe SSDs Dell Networking S4810 switches Dell Compellent SC8000 storage array Audience This technical white paper is intended for solution architects, storage network engineers, system administrators, and IT managers who need to understand about designing, properly sizing, and deploying Horizon View-based VDI solutions by using Dell infra design, properly sizing, and deploying Horizon Viewbased VDI solutions by using Dell infrastructure. It is expected that the reader has a working knowledge of the Horizon View architecture, vsphere system administration, iscsi SAN network design, and Dell Compellent SAN operation. 6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

7 2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for improved storage workload performance. Applications write directly to the cache pool, the acknowledgement is sent back to the application, and in the background, the I/O is flushed to the external storage array. Data is copied in to the cache pool when it is accessed (read) by application and is available from the cache pool for reread operations. Also, data that is written into the cache pool by the application is then available for reread operations from the application. A high-speed link to other cache nodes in the Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data, even if a single node in cache pool stops working. Fluid Cache for SAN provides a single management interface and provides other capabilities such as cache-aware snapshots and replication and compression. Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between server and storage. Three nodes are required to run Dell Fluid Cache for SAN software. Two of these three nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each, and the network for private cache network is based on the low-latency RDMA protocol. The RDMA network handles the cache pool communication between the nodes. Creation and management of the Fluid Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through automatic cache server discovery. Figure 1 Dell Fluid Cache for SAN communication 7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

8 Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive workloads because it provides extremely fast and low-latency server-side write back caching. Because writes are mirrored across high-speed network and later destaged to the SAN with significant write coalescing, this solution can sustain significantly higher IOPS/VM than an external hybrid or all-flash array based solution could. 8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

9 3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here. Figure 2 VDI solution architecture 3.1 Software: Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure and managed service from a centralized infrastructure. A Horizon View infrastructure consists of many different software, network, and hardware layer components. This section presents an overview of the key Horizon View components and technologies that are critical for successful design and deployment of the VDI environment. 9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

10 3.1.1 Horizon view components A functional list of Horizon View components used in this solution is given in the table here. Table 1 Horizon View components Component Client Devices Description Personal computing devices used by end users to run the Horizon View Client. These can include special end-point devices such as Dell Wyse end points, mobile phones, and PCs. Horizon View Connection Server A software service that acts as a broker for client connections by authenticating, and then directing the incoming user requests to the appropriate virtual desktop, physical desktop, or terminal server. Horizon View Client Horizon View Agent Software that is used to access the Horizon View desktops. A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server. Horizon View Administrator vcenter Server Horizon View Composer A web-based administration platform for the Horizon View infrastructure components. Central administration platform for configuring, provisioning, and managing VMware virtualized data centers. A service running with Horizon View servers, used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements Virtual desktops Virtual desktops can be classified in to two major categories: persistent and non-persistent. Persistent desktop environment: All configuration and personalization on the assigned desktop is kept for the user-between sessions. When using persistent desktops, an administrator usually has to provision additional storage along with other administrative requirements such as patching and upgrading of individual desktops. Non-persistent desktop environment: Users are dynamically assigned virtual desktop VMs from a pool of resources during login. This type of virtual desktop does not retain any information between sessions. At logoff, all changes are simply discarded and the virtual desktop is returned to the original state. Patching and upgrading non-persistent desktops requires only making the change to the base image and refreshing or recomposing the virtual desktop pool. Thus, these desktops are much easier to manage, but lack the potential for persistent user customization. 10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

11 3.1.3 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single entity by the Horizon View Administrator interface. Horizon View desktop pools allow administrators to group users depending on the type of service the user requires. There are two types of pools Automated and Manual. In Horizon View, an Automated Pool is a collection of VMs cloned from a base template, while a Manual pool is created by the Horizon View Manager from existing desktop sources, physical or virtual. For each desktop in the Manual pool, the administrator selects a desktop source to deliver Horizon View access to the clients. VMware View Personas profile management features can be used to achieve persistent desktop-like behavior on non-persistent desktops. By using these features, an administrator can design a user account where the configuration settings are written to a remote profile that is stored separately from the virtual desktop image files. This reduces the need for additional management on individual virtual desktops while still providing a customized user experience Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration are possible when using VMware-linked clones. A linked clone is a duplicate VM that shares the same base image with the original VM, but has separate differential data disks to track the differences from the original one. Each linked clone functions as an independent desktop VM with its own unique identity. Because linked clones share the same base image, they consume significantly less storage disk space than a set of completely independent VM images. Temporary system data and other data, unique to each linked clone desktop VM, are written to separate differential data storage and these temporary changes are discarded during restart and/or user logoff. Persistent data such as user profiles, applications, and user data can be optionally redirected to a CIFS share. With this model, software maintenance updates, antivirus remediation, and patches need to be applied only on the base image. These base image changes automatically take effect on all linked clones without affecting any user settings and data. To configure linked clones, the administrator creates a snapshot of a parent VM image with the required OS, settings, and software installed. Horizon View Composer first creates a full replica (clone) of the parent VM, and then uses this replica to create linked clones. The replica can be placed on the same data store as the linked clones or on a separate data store. More information about configuring linked clones can be found in the Creating Desktop Pools section of the VMware Horizon View Online Library here Hypervisor platform: VMware vsphere 5.5 VMware vsphere 5.5 is the enterprise virtualization platform used for building VDI and cloud infrastructures. VMware vsphere 5.5 includes three major layers: virtualization, management, and interface. The virtualization layer includes infrastructure and application services. The management layer is central 11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

12 for configuring, provisioning, and managing virtualized environments. The interface layer includes the vsphere client and the vsphere web client. Throughout the solution, all VMware and Microsoft best practices and prerequisites for core services were used (NTP, DNS, Active Directory, and others). 3.2 Hardware: Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon View based, high IOPS type VDI deployment that leverages Fluid Cache. An eight-node vsphere server cluster is used to host the virtual desktops. Each of these server nodes has a direct-attached PCIe SSD that is added to the Fluid Cache pool, thus making each server a Fluid Cache Provider (a server contributing to the Fluid Cache capacity). The eight PCIe SSDs were distributed among all the servers to better balance the load on the Fluid Cache server. Fluid Cache server 1. These servers were connected by using a private caching network to provide the Fluid Cache functionality. Also, the servers were connected through a separate management/vdi client network and a 10 GB Ethernet iscsi SAN network. Another two-node vsphere server cluster is used to host the VDI infrastructure VMs such as vcenter server, View Connection server, View Composer server, SQL Server, and Active Directory etc. These infrastructure servers were connected to the management network and the iscsi SAN network. The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs, 15K SAS HDDs, and 7.2K NL-SAS HDDs to provide the optimal performance and capacity needed for the solution. Two switches are stacked together for different networks to provide redundancy in the networking layer. Ideally, 40 GB Ethernet switches are recommended for the cache network. While 1 GB Ethernet switches can be used for management network, it is better to use 10 GB Ethernet switches combining management and VDI client networks. The same 10 GB Ethernet switches can be used for iscsi SAN also (with different network traffic segmented by VLANs), provided they have adequate bandwidth needed for the specific VDI deployment. Information about how this reference architecture was developed ensuring the optimal utilization across the servers, switches, and storage arrays, is discussed later in the following sections of this technical white paper. 1 Fluid Cache does not require all servers to be a Fluid Cache Provider. For example, in this case, four servers could have two PCIe SSDs each. This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache. However, the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers. 12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

13 (Server 1) (Server 2) Figure 3 Infrastructure Set-up for VDI Solution 1. Enterprise Manager Console 2. Management and VDI Client Network 3. vsphere Servers hosting virtual desktops 4. Cache network switches (2) 5. SAN switch 6. Storage Center controllers (2) 7. Storage Center expansion enclosures (2) 8. Server hosting VDI infrastructure VMs 13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

14 4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View virtual desktops, including infrastructure components, networking, and storage subsystems. 4.1 Host design considerations The entire VDI solution was installed in two vsphere server clusters. The clusters included: Figure 4 vsphere server clusters Infrastructure Cluster: Two Dell PowerEdge R720 servers, hosting VMs for Active Directory services, VMware vcenter 5.5 server, Horizon View Connection server (primary and secondary), View Composer server, Microsoft Windows Server 2012 R2 based file server, and SQL Server 2012 R2. View Client Cluster: Eight Dell PowerEdge R720 servers hosting the virtual desktops. Each server had o 2 10 core Intel Xeon CPU o 256 GB RAM o GB Dell Express Flash PCIe SSD o 1 Mellanox Connect X3 card o 1 Dual-port Broadcom NetXtreme II BCM Gigabit NIC o 1 Quad-port Broadcom NetXtreme BCM5720 Gigabit NIC Along with the other servers, the above servers, 40 LoginVSI launcher VMs were used to generate VDI workload. They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation purposes. 14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

15 4.2 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vsphere 5.5 installed. Figure 5 vsphere host network configuration Three network switches are used in the Fluid Cache for VDI implementation. One Force10 S55 1 GB switch for all management traffic and VDI traffic. The management traffic includes hosts and vsphere management, Compellent storage management, and so on. The networks are segregated by using VLANs to separate different types of traffic. One Dell Force10 S GB switch is used for Fluid Cache cache network which supports all the traffic between cache layer on eight VDI VM hosts. Another Force10 S GB switch is used for iscsi network between infrastructure hosts, VDI VM hosts, and Compellent SC8000. Appendix B has extended information on the vswitch configuration for each vsphere host. 15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

16 4.3 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center Operating System (SCOS) 6.5. All two front-end ports were 10 GB iscsi and all two back-end ports were six GB serial-attached SCSI (SAS). The array used two external enclosures with Write Intensive (WI) SSDs comprising Tier 1, and 15K SAS HDDs comprising Tier 2 for performance. Also, 7.2 NL-SAS drives were used in Tier 3 to provide capacity for user data. Table 2 summarizes the storage hardware configuration. Table 2 Storage hardware components Storage role Type Qty. Description Controllers SC System Center Operating System (SCOS) 6.5 Enclosures External 2 24 bay 2.5 disk drive enclosure Ports Ethernet 10 Gbps 2 Front end host connectivity SAS - 6 Gbps 4 Back end drive connectivity Drives 400 GB WI SSD active with 1 hot spare 300 GB 15K SAS HDD active with 1 hot spare 4 TB 7.2K NL-SAS HDD active with 1 hot spare The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity technology for efficient capacity allocation. Table 3 lists the volume layout used for the infrastructure functions including user data. Table 3 Volume layout for hosting infrastructure components and user data Volume name Size Purpose Infrastructure 500 GB Storage for Active Directory, SQL Server, vcenter Server, View Connection Server, View Composer, and File Server UserSpace 2 TB Storage for User profiles and folder redirection space (Average, 2.5 GB per user) Along with the infrastructure volumes, the storage array also provided shared storage for hosting the virtual desktops. The volume layout used for configuring the base image (View Composer Replica) and VDI volumes on the array is shown in Table Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

17 Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops Volume name Size Purpose View-Replicas1 and GB each Storage for base image for VDI deployment VDI-Images1 through GB each Storage for VDI VMs in VDI Cluster. Each volume hosted 100 desktops. 4.4 vsphere host network configuration VMware vsphere 5.5 hypervisor was installed on all servers. The network configuration on each of those hosts is described here. Each vsphere host was configured with five virtual switches, vswitch0, vswitch1, vswitch2, vswitch3, and vswitch4 to separate different types of traffic on the system. Table 5 vswitch vswitch0 vswitch configuration in vsphere hosts Description Management Network vswitch1 and vswitch2 vswitch3 iscsi SAN Fluid Cache VLAN vswitch4 VDI LAN For additional information about individual vswitch configuration, refer to Appendix B in the Dell technical white paper. 4.5 Horizon view configuration Horizon View 6.0 was installed by using the documentation provided by VMware. Horizon View installation documentation: Table 6 Specific configuration used in the tests Purpose Count Type Memory CPU Horizon View Connection Servers 2 VM 16 GB 8nos View Composer Server 1 VM 8 GB 8nos 17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

18 4.6 Windows 7 VM configuration Following the guidelines from VMware and Login VSI, the Windows 7 base image was generated based on a generic base VM with the following properties: VMware Virtual Hardware version 8 Two virtual CPU 3 GB RAM with 1.5GB reserved 25 GB virtual hard drive One virtual NIC connected to the VDI network Windows 7 64-bit OS Also, the base image was customized by using the VMware Horizon with View Optimization Guide for Windows 7 and Windows 8, available at this location: OptimizationGuideWindows7-EN.pdf 18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

19 5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN for high IOPS type VDI environment. 5.1 Test objectives As noted in Section 1.1, the test objectives were: Develop an optimal end-to-end infrastructure design for a Horizon View and vsphere based high user type of VDI solution deployed by using the Fluid Cache, Compellent storage, PowerEdge servers, and Dell Networking switches Determine the performance at every layer of the VDI solution stack under high IOPS workload, For example, desktops generating IOPS/VM at steady state Determine the performance impact of peak I/O activity such as boot and login storms 5.2 Test tools All tests were conducted by using Login VSI 4.0 as the workload generator and user experience analyzer tool. Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop environments such as Server Based Computing (SBC) and VDI. Note: More information can be found at the Login VSI website: In addition to Login VSI, Iometer is used in desktop VMs to simulate high IOPS conditions. Iometer is invoked in desktop VMs by using custom scripting of Login VSI workloads. Note: More information can be found at the Iometer project website: Load generation First, the Medium workload from Login VSI was used to simulate the standard user workload. The characteristics of the Medium workload are: Up to five applications are started simultaneously. Applications include Microsoft Internet Explorer, Microsoft Word, Microsoft Excel, Microsoft PowerPoint, PDF reader, 7-Zip compression software, Movie player, and FreeMind. After a session is started, the medium workload repeats approximately after every 48 minutes. During a loop, the response time is measured after every 3 4 minutes. Idle time is about two minutes in each 48-minute loop. Type rate is approximately 160 milliseconds per character. After the test by using Login VSI Medium was complete, tests were rerun with Login VSI Medium and Iometer in desktop VMs to simulate high IOPS VDI workload. While the Login VSI Medium generates Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

20 IOPS/VM, the latter method was able to generate IOPS/VM. For these tests, each VM in the Horizon view pool is created with standard LoginVSI contents and applications. Also, Iometer is installed on each VM. After the user logs in, a customized logon script starts the Iometer with required I/O specification (.icf file) Monitoring tools The following monitoring tools were used: Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage array performance VMware vcenter statistics for vsphere performance Login VSI Analyzer for end user performance statistics Detailed performance metrics were captured from the storage arrays, hypervisors, virtual desktops, and the load generators during the tests. 5.3 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with acceptable user experience by using Fluid Cache for SAN. VDI configurations involve many components at different layers application, hypervisor, server, network, and storage. As a result, multiple metrics need to be captured at different layers to ensure that the environment is healthy and performing optimally and appropriately for all users. The specific test criteria are described in the following sections Storage capacity and I/O latency The typical industry standard latency limit for storage disk I/O is 10 milliseconds. Maintaining this limit ensures good user application response times when there are no other bottlenecks at the infrastructure layer. In addition, Dell recommends to maintain a 10 percent spare disk space on the storage array for optimal performance System utilization at the hypervisor Even though the primary focus of these tests was storage characterization, additional metrics at the hypervisor infrastructure layer were defined to ensure solution consistency. These were: CPU utilization on any vsphere server must not exceed 85 percent Minimal memory ballooning on the VMs Total network bandwidth utilization must not exceed 90 percent on any one link TCP/IP storage network retransmissions should be less than 0.5 percent 20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

21 5.3.3 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to ensure that all the desktops had acceptable levels of application performance. Login VSI uses the VSImax parameter to determine the maximum number of sessions that can be obtained from a deployed solution. The calculation methodology used in VSImax is available here: Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface. Each pool was built from a Windows 7 base image. The Windows 7 configuration information is available in Section 4.6. Desktop pool properties: Automatic Desktop Pool Users are assigned using Floating assignments. View Storage Accelerator is enabled for all hosts with a refresh period of seven days. 800 desktops were deployed across eight hosts (100 desktops a host) Replica images were stored on a separate volume 21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

22 6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key findings from each test. The testing was focused on the high IOPS workload profile. 6.1 Test scenarios The following tests were conducted to gather results and analysis on the solution stack. 1. Boot storm: Boot storms represent the worst-case scenario where many virtual desktops are turned on at the same time and they all contend for the system resources simultaneously. This test was used to evaluate if the storage array hosting the desktops was capable of handling huge variation in storage I/O, without causing significant impact on other services. 2. Login storm: Login storms also represent a high IOPS situation where many users are logging in to their virtual desktops at the beginning of a workday or a shift. In this test, all the desktops were pre-booted and left in an idle state for more than 20 minutes to let their I/O settle before running the Login VSI Medium workload to simulate users logging in to their virtual desktops. 3. Steady state workload for standard users with normal IOPS: After the login storm for the previous test was completed, the Login VSI Medium workload was allowed to run for at least one hour to simulate the real-world scenario of users performing their daily tasks. The VSImax (Dynamic) parameter from Login VSI is used to evaluate the end-user experience of simulated users working on their virtual desktops throughout these tests. 4. Steady state workload for users with high IOPS: The previous test was repeated with the Login VSI Medium workload and Iometer scripts in desktop VMs as described in Section to simulate real-world heavy users performing their daily tasks with high IOPS. The VSImax (Dynamic) parameter from Login VSI is used to evaluate the end-user experience of simulated users working on their virtual desktops throughout these tests. The following sections provide results from the boot storm, login storm, and steady state testing for the Fluid Cache for SAN based VDI solution. 22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

23 6.2 Boot storm I/O To simulate a boot storm, the virtual desktops were reset simultaneously from the VMware vsphere client. Figure 6 shows the I/O pattern on the Fluid Cache for the boot storm. Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array With 800 desktops, the boot storm generated about 115,000 total IOPS with a majority of them being 'write' operations. All desktops were available for use in less than four minutes. 23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

24 6.3 Login storm and steady state for standard users (LoginVSI Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after prebooting the virtual desktops. The peak IOPS during the login storm observed by the vsphere servers hosting the desktops was about 6,500 IOPS (8 10 IOPS a VM). In a standard user environment, login storms generate significantly more write IOPS than a boot storm or steady state because of multiple factors such as: User profile activity Starting operating system services on the desktop First start of applications After a virtual desktop has achieved a steady state after user login, the Windows 7 OS has cached applications in memory and does not need to access storage each time the application is started. This leads to lesser IOPS during the steady state. Figure 7 here shows the various I/O characteristics during the login storm and steady state of these tests. 24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

25 Figure 7 IOPS and Cache Hit for the standard user test On the Fluid Cache layer, the maximum IOPS reached 6,500, with cache-hit reaching 100 percent, and read-hit around 95 percent. As shown in the Figure 8 here, the throughput peaked at 98 MBps with a low latency of less than 2 msec. 25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

26 Figure 8 Throughput and Latency for the standard user test Server host performance During the login storm and steady state of the test, the vsphere host CPU, memory, network, and storage performance were measured on all the servers that hosted the virtual desktops. The performance of one such vsphere server is given here. The other vsphere servers had similar performance characteristics. Statistics for the vsphere hosts were captured by using VMware vcenter Server. The figures here show the CPU, memory, and network utilization for boot storm, login storm, and steady state of one of the vsphere servers hosting the virtual desktops. The results shown here are for a test run with 800 no standard, user desktops in the desktop pool. 26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

27 GB Percent CPU Performance :20 10:45 11:10 11:35 12:00 12:25 Time Figure 9 Average CPU performance per core on one vsphere host during login storm and steady state 300 Memory Performance :20 10:40 11:00 11:20 11:40 12:00 12:20 Time Granted Swap used Shared common Figure 10 Disk space usage during login storm and steady state 27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

28 msec kbps Network Performance :20 10:45 11:10 11:35 12:00 12:25 Time Figure 11 Overall network performance during login storm and steady state 2.5 Storage adaptor performance :20 10:45 11:10 11:35 12:00 12:25 Time Figure 12 Storage adapter performance during login storm and steady state 28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

29 The key observations from the statistics were: CPU utilization was less than the 85 percent threshold throughout the test. Active disk space usage was about 80 percent during the boost storm and about 60 percent during login storm and steady state. There was minimal-or no memory ballooning observed. Network utilization was about 45 percent, which included all the networks such as iscsi, SAN, VDI LAN, Management LAN, and vmotion LAN. Average read- and write latencies at the storage adapter level were very close to the observed latencies in Fluid Cache 2 msec Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI. The graph clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or inactive sessions. This means that the array is capable of supporting the 1,000 desktops and all users have acceptable response times for applications that the user is has started. Figure 13 Login VSI user experience monitoring for 800 standard user desktops 29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

30 6.3.3 Standard user test results summary The key observations from the test results are listed here. The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a standard user type of I/O activity. The VDI I/O was mostly write-intensive I/O with more than 98 percent write-only operations and less than 2 percent read-only operations. None of the system resources on the vsphere servers hosting the virtual desktops reached maximum utilization levels at any time. When 800 users were logged in within 20 minutes, the Fluid Cache for SAN VDI solution was able to handle this login storm easily with low latency it delivered the required 6,500 IOPS with less than 2 milliseconds of write latency with a 99 percent write VDI I/O workload. 6.4 Login storm and steady state with high IOPS (LoginVSI Medium + Iometer) As mentioned earlier, Iometer was used in desktop VMs alongside the Login VSI Medium workload to simulate high IOPS type of VDI environment. To mimic actual VDI workload profile, the following Iometer profile was used: 20 KB block size, 80 percent write, 75 percent random, with 25 msec burst delay Figure 14 here shows the various I/O characteristics during the login storm and steady state of these tests. Figure 14 IOPS and Cache Hit for the high IOPS test On the Fluid Cache layer, the maximum IOPS reached was approximately 72,000 (or 90 IOPS/VM) with cache write-hit 100 percent and read-hit around 95 percent. As shown in the Figure 15, the throughput peaked at greater than 900 MBps with a peak latency of approximately 7.5 msec. 30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

31 Figure 15 Throughput and Latency for the high IOPS test 31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

32 6.4.1 Server host performance Similar to the standard user test, statistics for the vsphere hosts were captured by using VMware vcenter Server during the high IOPS (heavy user) test also. There are no significant differences in CPU, disk space, and network utilization between standard users and heavy users. The storage adapter latency is also showing similar on hosts and observed on Fluid Cache User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the heavy user test. The graph shows that the VSImax (Dynamic) value was 796, indicating that the solution is capable of supporting the 800 user, high IOPS desktops with 90 IOPS/VM. Figure 16 Login VSI user experience monitoring for 800 user, high IOPS desktops 32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

33 6.4.3 High IOPS (heavy user) test results summary The key observations from the test results are listed here. The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a high user type of I/O activity. The VDI I/O was mostly write-intensive I/O with more than 98 percent write-only and less than 2 percent read-only operations. None of the system resources on the vsphere servers hosting the virtual desktops reached maximum utilization levels at any time. When 800 users were logged in within 20 minutes, the Fluid Cache for SAN VDI solution was able to easily handle this login storm with low latency. Subsequently it was able to handle 72,000 IOPS at high IOPS steady state with 90 IOPS/VM with a maximum of 7.5 msec latency. 33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

34 7 Best practices This section provides the best practices derived from the testing and analysis in Section Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder redirection. This preserves user profiles and user data across boots while using non-persistent virtual desktops. Also, Dell recommends to use a high performance file service to provide the profile and folder redirection. A separate array may be used to host these volumes for best performance Boot and login storm considerations Section 6.2 demonstrated the Fluid Cache for SAN performance under boot storm. To avoid any potential I/O bursts because of boot storm and degraded user experience and performances, Dell recommends that all or portion of desktops be prebooted. Connection brokers such as VMware Horizon View provide the functionality to configure number of standby desktops Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a VDI environment. This includes disabling some services, which may not be required. This can improve performance for the end user. VMware has a specific set of recommendations and settings for Windows 7 and Windows 8 that allow for faster logins, quicker screen refreshes, and generally better performance. The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here: VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services, in the case of VMware Horizon View solution as tested here, the vsphere Server, VMware Horizon View Servers, and SQL Servers. Ideally, these should be running on clustered hosts with VMware vsphere DRS (distributed resource scheduler) and HA (high availability) enabled. 7.2 Server host The vsphere servers hosting the infrastructure service providers and the virtual desktops are recommended to be configured as follows: 34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

35 Follow VMware and Dell best practices for installing and configuring vsphere. Separate virtual switches to segregate iscsi SAN traffic, VDI traffic, vmotion traffic, and Management network traffic. Each network path must be assigned to a minimum of two physical NICs for high availability. VMware Knowledge Base article about best practices for installing vsphere 5.5: Network layer Dell recommends that at least two physical NICs on each vsphere server be dedicated to the VDI network. Use VLANs to segregate different types of network traffic on the same physical network. In this case, Dell recommends to separate the infrastructure, vmotion, and VDI LAN traffic in to separate VLANs. Do not use VLANs to segregate iscsi SAN and Fluide Cache traffic. It is required that SAN and Cache traffic be on separate dedicated physical network to provide the best performance. Virtual switches in vsphere have a default limit of 120 ports. If the number of virtual desktops on each host exceeds the available ports, vswitch properties should be changed to support the required number of virtual desktops. This change requires a restart of the host vsphere server. On iscsi SAN switches, Spanning tree must be disabled on switch ports connected to end devices for server and storage ports. The PortFast setting must be enabled in the switch configuration for these ports. Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iscsi network. More information about configuring Dell Networking switches for use with Dell Storage iscsi SANs is available here: Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective performance in VDI environments. Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the server. By providing a single infrastructure for data at both high- and low ends of the performance spectrum, Fluid Cache for SAN with Storage Center 6.5 array software eliminates the tradeoffs between server performance and full-featured SAN benefits such as reliability, manageability, and data protection. Dell recommends to have separate volumes for base image and virtual desktops. This enables better manageability of the volumes, easier performance monitoring, and allows easy future growth. Dell recommends to use a separate high performance file service to provide file shares for roaming profiles and user shares. 35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

36 8 Conclusion The technical white paper demonstrates how a high IOPS, 800-user, virtual desktop environment can be deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN. The storage I/O characteristics under various VDI workload scenarios (boot storm, login storm, and steady state) along with performance characteristics throughout the VDI stack (for example, vsphere server performance and user experience) demonstrate the optimal configuration of the infrastructure used for this VDI deployment. For more information about Fluid Cache, contact your Dell account manager. 36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

37 A Horizon view solution configuration Table 7 Hardware components Hardware components: Description Virtual Desktops 4 Dell PowerEdge R720 Servers (Fluid Cache Providers): 2 Intel Xeon E GHz Processors 192 GB RAM 1 Connect-X3 card GB Dell Express Flash PCIe SSDs 1 Dual-port Broadcom NetXtreme II GbE NIC ESXi 5.5 U2 on all R720 servers Windows 7 (64 Bit) VMs Infrastructure Servers Login VSI Launchers 4 x Dell PowerEdge R720 Servers (Fluid Cache Clients): 2 Intel Xeon E GHz Processors 192 GB RAM 1 Connect-X3 card 1 Dual-port Broadcom NetXtreme II GbE NIC 2 x Dell PowerEdge R720 servers: 2 Intel Xeon E GHz Processors 96 GB RAM GB 10K SAS internal disk drives 1 Dual-port Broadcom NetXtreme II GbE NIC 8 x Dell PowerEdge M610 servers 2 Intel Xeon E GHz Processors 16 GB RAM GB 10K SAS internal disk drives 1 Dual-port Broadcom NetXtreme II GbE NIC ESXi 5.5U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2. Active Directory VMware Horizon View 6.0 Server 1 VMware Horizon View 6.0 Server 2 VMware vcenter Server 5.5 update 2 VMware Horizon View Composer SQL Server File Server ESXi 5.1 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions. 37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

38 Network Storage Performance Monitoring Management, VDI LAN, 1 Dell Force10 S55 1Gb Ethernet Switch iscsi SAN 1 Dell Force10 S Gb Ethernet Switch Cache network 1 Dell Force10 S Gb Ethernet Switch 2 Dell Compellent SC8000 controllers 4 6Gb SAS 4-port, PCI-E, Full-height cards for back-end connectivity 2 10Gb iscsi, 2 port, PCI-E, Lowprofile IO cards for front end connectivity 1 Dell Compellent SC200 disk enclosures 12 4TB NL-SAS 6Gb, 7.2K, 3.5 drives Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool (?) vcenter Performance monitoring Liquidware Stratusphere UX One Force10 S4810 switch might suffice for all the cache, iscsi SAN, VDI LAN and management traffic User Data, Infrastructure VMs, Virtual Desktops Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop 38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

39 Table 8 Software components Software components Description / Version Dell Fluid Cache for SAN 2.0 Dell Compellent Storage Center 6.4 Dell Compellent Enterprise Manager 6.4 VMware Horizon View Server 6.0 VMware Horizon View Composer 6.0 VMware Horizon View Agent 6.0 VMware Horizon View Client 64-bit 6.0 VMware ESXi Hypervisor VMware vcenter Server 5.5 U2 5.5 U2 Microsoft SQL Server 2008R2 Enterprise x Client VM OS Management VM OS Microsoft Windows 7 Enterprise x64 SP1 Microsoft Windows Server 2008 Enterprise R2 x64 SP1 Microsoft Office MS office 2010 Standard Service Pack 1 Login VSI Version 4.0 Iometer Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

40 B vsphere host network configuration Each vsphere host was configured with four virtual switches - vswitch0, vswitch1, vswitch2, and vswitch3. B.1 vswitch Management traffic vswitch0 provides connection paths for all management LAN traffic. The first partition of the physical adapters from the two on-board NICs (Fabric A) was assigned to this switch. Figure 17 vswitch0 Management LAN B.2 vswitch - iscsi Two partitions from the physical adapters in Fabric A are assigned to this virtual switch. This vswitch carries the traffic required to provide VMware vmotion services. Figure 18 vswitch1 vmotion LAN 40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN

41 B.3 vswitch Fluid Cache network This virtual switch provided paths for all the iscsi SAN traffic. Two partitions of the physical adapters from the two on-board NICS (Fabric A) were assigned to this virtual switch. Figure 19 vswitch2 iscsi virtual switch B.4 vswitch3 Two 10 GB physical adapters in Fabric B are assigned to this virtual switch. This vswitch carried all network traffic for the VDI LAN. Figure 20 vswitch3 VDI LAN 41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN