VMware Virtual Desktop Infrastructure Planning for EMC Celerra Best Practices Planning

Transcription

1 VMware Virtual Desktop Infrastructure Planning for EMC Celerra Best Practices Planning Abstract This white paper provides insight into the virtualization of desktop systems using the EMC Celerra IP storage protocols to expedite systems deployment, improve desktop systems reliability, and reduce the total cost of ownership for end-user desktop systems. February 2008

2 Copyright 2008 EMC Corporation. All rights reserved. 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. For the most up-to-date listing of EMC product names, see EMC Corporation Trademarks on EMC.com All other trademarks used herein are the property of their respective owners. Part Number H4194 Best Practices Planning 2

3 Table of Contents Executive summary...4 Introduction...6 Audience... 6 Terminology... 6 Technology overview...7 Virtualization server... 7 Virtual Desktop Manager... 7 Storage system... 8 Celerra storage provisioning... 9 LUN masking Virtual Desktop installation and configuration iscsi snap management...14 ESX integration Swap file configuration Celerra network considerations System power up Snap image revocation Conclusion...20 References Best Practices Planning 3

4 Executive summary With the successful adoption of virtual computer systems, customers have continued to look for virtualization solutions that allow them to improve their business practices. One such area undergoing much evaluation and adoption is the centralization of desktop systems into the data center using VMware ESX virtualization technology. This solution is called Virtual Desktop Infrastructure (VDI). VDI provides an alternative approach to desktop provisioning and support by encapsulating the Virtual Desktop system image within a VMware virtual machine in the ESX environment. End users connect to the desktop environment from a thin client device or system that supports remote connection protocols over local area, wide area, and wireless networks. Unlike other approaches to server-based computing, VDI users connect to a self-contained operating system instance that is independent of other virtual machines running in the environment. However, since VMware encapsulates each desktop image within a set of files, the service level and systems management processes can be significantly improved through enterprise-class hardware and storage systems. VDI improves upon the limiting value areas of traditional enterprise desktop systems, offering the ability for cost savings and increased reliability, security, and manageability of the desktop systems. It also improves resource efficiency in that desktop systems are typically the most poorly utilized in the corporate environment while also carrying significant support costs to the IT department. With the shift to energy efficiency and green computing, VDI allows for systems to share a reduced set of hardware resources while allowing for improved performance and reducing the amount of energy required to support the systems. From a security standpoint, VDI offers the ability to secure corporate assets in the data center where their access can be controlled and monitored. Additional benefits include increased system availability by using advanced VMware functionality such as ESX Server clustering, DRS, and VMotion to protect against hardware failures and balance system desktop systems across the available resources. It offers the ability to migrate all of the isolated desktop disk drives to a higher class of RAID-protected storage with integrated data backup, replication, and recovery features. With a more mobile workforce and end-user community, desktop access can be extended to just about anywhere you can get onto the Internet and access your organization s network. Depending on the applications and role of the users, one of several access methods would be employed to establish the client interaction and user desktop assignment. The following list and Figure 1 provide some examples of how Virtual Desktops could be employed. Defining a pool of desktop systems, a help desk, or academic environment may leverage one of the hardware-based thin client devices and connect to the desktop system using one of the remote desktop protocols that the device offers. A knowledge worker or corporate partner may retain a laptop to do local tasks but also leverage a remote connection or web access to log in to a desktop environment where a collaborative project is being conducted. A secure perimeter could be established disallowing any classified materials to exist on a user s portable desktop or laptop systems. In this case all access is conducted over the network while Virtual Desktop policy rules define a user s entitlements and enforce their access. Best Practices Planning 4

5 Figure 1. Virtual Desktop Infrastructure topology The synergies that exist from a data storage perspective are derived from the complementary nature in which an IP storage system can facilitate and improve upon some of the cyclical tasks of the VDI system. EMC Celerra IP storage provides significant benefits to the overall deployment and systems management aspects of VDI. Offering a multi-protocol product with iscsi LUNs for the VMFS Datastores and CIFS file shares to store persistent data, Celerra provides an attractive consolidated platform solution to satisfy all of the storage requirements of the VDI environment. The solution provides a method to quickly replicate and deploy virtual machine images within a Virtual Desktop environment. It uses Celerra virtually provisioned file systems for CIFS shares and virtually provisioned iscsi LUNs for VMFS Datastores to make efficient use of the disk resources in the environment. Architectural benefits are realized from the creation and management of golden system copies that can be customized and deployed when application updates or operating system changes are required. A common example would be in the area of patch management. Rather than applying patches to each individual desktop in the environment, patches can be applied to the centralized golden copy image and propagated throughout the environment using the iscsi LUN replication capabilities of Celerra. Likewise multiple desktop images can be customized to support a specific line of business or set of user applications and, as application changes are made to one or more of the images, updates can be applied to the golden copy and quickly pushed out to the virtual machine pool. Figure 2 provides a simplified view of this deployment process. Best Practices Planning 5

6 Figure 2. Celerra Virtual Desktop deployment process overview The remainder of this white paper provides additional details on the architecture and solution as well as some considerations and best practices for implementing VDI with Celerra. Introduction This white paper provides an overview of an integrated solution combining Virtualization technology from VMware with IP Storage Virtualization and Replication technologies from EMC s Celerra storage system. The solution offers a repeatable process for rapid deployment and updates of virtual machine images using Celerra iscsi replication technologies. Audience This paper is intended for storage and systems administrators as well as systems architects interested in leveraging the capabilities of IP storage, virtual storage devices, and Virtual Desktop Infrastructure. The paper provides a mix of high-level concepts with implementation details. Terminology Celerra Data Mover Networked storage server that runs the Data Access in Real Time (DART) operating system to process storage requests. iscsi target - An iscsi endpoint, identified by a unique iscsi name, which executes commands issued by the iscsi initiator. Link Aggregation - A high-availability feature based on the IEEE 802.3ad Link Aggregation Control Protocol (LACP) standard allowing Ethernet ports with similar characteristics on the same switch to combine into a single virtual device/link with a single MAC address and potentially multiple IP addresses. LUN (Logical Unit) - For iscsi on a Celerra Network Server, a logical unit is an iscsi software feature that processes SCSI commands, such as reading from and writing to storage media. From an iscsi host perspective, a logical unit appears as a block-based disk device. Virtual Desktop Infrastructure (VDI) A set of software products that provide services and management infrastructure for centralization of desktop operating environments using virtual machine technology. Best Practices Planning 6

7 Virtual Desktop Manager (VDM) - A server-based computer offering that provides desktop environments as an enterprise hosted service. Technology overview The Virtual Desktop Infrastructure solution with EMC IP storage is made up of three separate technologies that have been integrated to form one seamless application. In this section we review the components individually and explain the role that each plays in the overall system. Virtualization server The primary technology used in VDI is a virtualization server such as ESX Virtual Infrastructure 3 from VMware. The role of the virtualization server is to support the virtual or guest machines within the hardware platform where the ESX Server software has been installed. The VMware server partitions and virtualizes physical system resources such as CPU, memory, network, and disk to create software-based computers. For the purposes of the solution being described in this paper, the virtualization software refers to ESX Virtual Infrastructure 3. ESX VI3 offers datastore support for SCSI storage over Fibre Channel, and iscsi or NFS storage over Ethernet networks. The ESX servers house the virtual machines or guest OS instances that are accessed by the end users. Since there will likely be many guest OS instances generated from a single image, the set of VDI desktops can be viewed as a pool of systems. The benefit is that a connection broker can redirect users to any one of a number of identical images from a pool. Additionally, changes or updates are applied to a single standard image and quickly deployed using Celerra writable snap technology. The virtual machine can be established in the traditional method of installing it from software distribution media, or an ISO image, and using the VMware Converter software to import the machine image from the hardware system to the ESX environment. The latter method might be the approach you would use when migrating hardware-based computers to software computers in the ESX environment. Virtual Desktop Manager Virtual Desktop Manager (VDM) provides the framework to establish and enforce policies within the VDI environment. There are several options available from VMware and third parties that deliver VDM functionality, providing a wide range of policy options for defining and enforcing system and user behavior. Some common features of a Virtual Desktop Management system are the ability to configure a set of virtual machines into a logical set of systems. Many of these systems offer integration into user databases such as Active Directory, allowing access policies to be applied based on user or group identity. VMware s VDM allows for multiple configuration options to establish virtual machine pools, and to assign individual users to them. It provides options for explicit machine assignment as well as policy-based assignment to persistent and non-persistent machine pools. Non-persistent VDI machine pools establish a set of systems that are not bound to a particular user. The benefit of this model is that it provides a set of systems that can be shared among a group of users in an adhoc or on-demand fashion. The flexibility of this model is complemented through the use of networked storage for user home directories or mapped drives. Celerra can offer the persistent storage through CIFS shares for Windows-based virtual machines, and NFS exported file systems for Linux VMs. Additional options aid in power and system resource conservation by powering the system off based upon defined criteria such as system idle time or a user logging off. The Virtual Desktop Manager also includes a connection broker. The connection broker or proxy provides session management and remote protocol connection support. At a functional level the connection broker is Best Practices Planning 7

8 responsible for enforcing the management policies and arbitrating access to the virtual machine system pool. The connection broker also supports the type of protocol that is used by the client system to access the guest virtual machine. Examples of access protocols are remote desktop protocol (RDP), which is a standard part of Windows XP and 2003, and VNC, which is an add-on software package. Storage system The final component of the solution is the storage used to support the environment. Up to this point the focus of this paper has been on the value realized through desktop virtualization, which includes benefits of resource efficiency, user mobility, and desktop reliability. Those benefits and some others can be significantly advanced through the inclusion of EMC s Celerra multi-protocol storage system in the VDI environment. The Celerra storage system provides networked storage using iscsi target LUNs, NFS exported file systems, and CIFS file shares. In some models such as the NS20 and NS40, it also includes Fibre Channel access. Additionally the system provides support for virtually provisioned storage devices that typically use very little allocated disk space. Applications and OS images will only allocate a fraction of the device space when a unique write is originated. These devices are storage objects that have very little storage burden on the storage system for creation of VMFS Datastores to house the VDI Virtual Desktop images. The EMC Celerra Data Mover provides SCSI termination through one or more iscsi targets. The iscsi target presents iscsi LUNs to the ESX environment using standard Ethernet connectivity with the option to enable advanced networking functionality for high availability and session load-balancing algorithms. Each iscsi target on Celerra supports up to 255 LUNs This allows for significant scalability in that the system can support additional connectivity points by associating additional targets with unused network interfaces, and scaling addressable capacity by increasing the number of LUNs associated with a target. Celerra also provides support for near instantaneous replicas of these iscsi LUNs. In the case of VDI and ESX a Linux-based snap management utility is available for incorporating the snap provisioning and LUN association into a scripted solution or application. In itemized format the solution leverages the following capabilities in order to seamlessly integrate with ESX for rapid deployment of virtual machine images using Celerra for reliable storage provisioning and data mobility. Celerra iscsi LUNs provide the support for Virtual Machine File System (vmfs3) file systems and leverage the virtual provisioning aspects of the product to minimize the amount of space required to support the VMs. Local iscsi LUN replicas can instantly create additional copies of the VMFS Datastores and the VMs. This provides a data mobility option for easily replicating and presenting images to the ESX environment. Remote Snap Management through the Linux Snap Management utility, providing for scripted solutions to manage all aspects of the VM storage container. Virtual Desktop Infrastructure for policy management and access to the VMs in the environment. Best Practices Planning 8

9 The remainder of this paper will focus on the steps involved in the desktop deployment cycle. This cycle represents a repeatable process of establishing the machine pool, as well as applying updates to the golden image or any of the applications. The impact of using the iscsi snap technology for deployment is that system updates such as operating system patches or upgrades are made to a single system, the golden image, and then redeployed to update the Virtual Desktop machine pool. Figure 3. Virtual Desktop deployment process with Celerra Celerra storage provisioning The first step in establishing the environment is to create the storage for the VMFS Datastores that constitute the staging ESX server and the Production Cluster where the VDI desktop pool will be generated. The solution leverages several Celerra iscsi LUNs and shared file systems with at least three iscsi LUNs being used to establish the VMFS Datastores for the virtual machines. The number of LUNs and associated datastores required in the environment are going to be based on several factors including the number of unique virtual machine images, and the desired number of production images. The minimum environment uses the three LUNs to support infrastructure services systems, virtual machine swap files, and the virtual machine images used to create the VM pool. The infrastructure LUN or VMFS Datastore is used to support the virtual machines that support the infrastructure services of the solution. The Linux host or virtual appliance is responsible for iscsi snap management and also provides the integration and task execution for the ESX Servers. The infrastructure Datastore is also where the user database, DNS, and DHCP servers would reside if you have chosen to virtualize those services in your environment. It lastly provides an area to support backup and clone copies of the golden images. A second VMFS Datastore will be used to support the swap files for the Virtual Desktop systems. Separating the swap file from the virtual machine files is a feature that was introduced in ESX version 3.5. Best Practices Planning 9

10 It allows for separation of vmdk and swap I/O in the event that the system runs short of virtual memory resources. For planning purposes it is important to understand the impact of the swap device sizing. The size of the LUN or LUNs used to support virtual swap files is going to be based upon several factors including the amount of physical memory in the ESX servers and the amount of memory reserved for each virtual desktop image. In a windows configuration for example, the ESX server will create a page file and allocate space which is equal to the amount of memory assigned minus amount of memory reserved for that VM. As an example if the golden image is configured with 512MB of memory, but no memory is reserved on the ESX server, each virtual desktop machine will allocate a 512MB page file which will be used to support OS paging operations. In a second example using the same image with 512MB of memory, we reserve 256MB of physical memory within the VM properties configuration. After deployment using this configuration, each VDI machine will have a page file size of 256MB. The third LUN will establish our virtual machine seed pool. This LUN or LUNs will be the source of all of the virtual machines that are created in the desktop environment. Each time the LUN is replicated it will increment the number of virtual machines available to the VDI pool. However since this is virtually provisioned storage, the storage system will not incur any storage penalty as we increase the number of replicas. An example of a small configuration is illustrated in Figure 4. ESX Cluster Figure 4. Celerra VDI architecture overview Best Practices Planning 10

11 As previously mentioned, the number of LUNs is tied directly to the implementation of VDI in the environment. With the potential exception of the Active Directory server, the infrastructure datastore contains a group of servers with fairly lightweight applications. In an environment with a high rate of Active Directory requests it may be necessary to allocate a separate LUN. The number of datastores used for the Virtual Desktop golden images is going to be based on the number of Virtual Desktop images that you wish to build in the production environment. There are some hard restrictions that need to be considered. VMware Virtual Desktop sizing guidance recommends a maximum of 40 running desktops 1 per ESX server, however, the actual number used in your environment may differ based on factors such as the desktop user I/O patterns and the number of core processors in the system. Core processor sizing would suggest between six and eight virtual desktops per core. This number could be fewer based on the desktop user profile and applications. In the current versions of ESX Server the maximum number of LUNs that can be addressed to ESX is 256. This means that we need to balance the number of Virtual Desktop images with the number of supported LUNs and the available ESX Server systems in the VDI environment. The Celerra solution offers two basic options. The first is to create unique VMFS volumes and establish one base or golden image within each datastore. Benefits of this option are that it can be managed independent of other desktop images in the VDI environment. In smaller environments it may be more manageable to isolate a specific application instance to its own LUN thus providing a finer level of control and avoiding any impact to that environment during updates. The second option is to create fewer VMFS Datastores and populate them with multiple Virtual Desktop images. Benefits of this option are that you can replicate more systems with fewer snaps. It is also a requirement for environments requiring more than 250 snap images based upon the max LUN limit in ESX Server. Note: If the environment requires that more than 250 virtual machines be presented to a single ESX Server, even if they are clustered, you need to include multiple VMs within a single VMFS Datastore. So, for example, a configuration with a single image and single LUN would work fine up to the 255 th LUN. Once the need for more than 255 arises, we would need to add another virtual machine image to the datastore. In order to take advantage of virtual (thin) provisioning of iscsi snapshots it is necessary to set a Celerra Data Mover parameter called sparsetws. The parameter is part of the Celerra NBS facility and enabling the parameter will limit the storage required for each new snap to roughly four 8k blocks or 32k of total disk space within the Celerra storage system. Through the use of Virtual Provisioning for Celerra volumes, iscsi LUNs and iscsi snapshots, we can create up to 1,000 snapshot images of the source images with an infinitesimally small percentage of the overall storage space allotted to the VMFS Datastore. The option exists to implement the solution using virtually provisioned storage on the Celerra system, adding further value by economizing the available disk space in the storage system. Virtually provisioned iscsi LUNs are created within virtually provisioned Celerra file systems. They are created using the server_iscsi command with the -vp argument as illustrated in the following command line example. (Note: This example assumes that an iscsi target named VDI already exists.) 1 VDI Server Sizing and Scaling white paper ( Best Practices Planning 11

12 By default the Celerra automatic file system extension will trigger at 90% and increment the size of the base file system that contains the virtually provisioned iscsi LUNs by 10% of its current value. So, for example, if the virtual provisioned file system size is 1 GB, the AutoFS extension will increase the size of the file system to 1.1 GB when the capacity reaches 900 MB. Since this is a pooled environment it is suggested that you reduce the high water mark to a lower value. Setting the value to 75% will trigger the 1.1 GB extension when the file system reaches 750 MB and another 10% extension when the file system reaches 825 MB. By the time it reaches 900 MB it will have been extended three times as opposed to one time when using the default value. The high water mark you define is largely based upon your end-user usage pattern and proactive planning for burst activity. If the system never hits the high water mark, file system will not need to be extended. Note: When creating the virtual provisioned file system it is recommended that you reduce the high water mark threshold to be less than the default value of 90% of the volume size. An alternate view of our environment presented through the VirtualCenter topology maps is provided in Figure 5. In this topology view there are two ESX data centers; one for the IT Department where the Active Directory, Linux Snap Manager systems, and Sales and Service golden images reside. The second data center is the production data center. In the state illustrated in the figure, the Virtual Desktops have not been created and the data center contains a four-node ESX cluster and a single datastore for the swap files. Infrastructure Production Figure 5. VirtualCenter topology map of a VDI environment using Celerra iscsi storage Best Practices Planning 12

13 LUN masking Masking is the functionality used to restrict a LUN s visibility from all but the intended client systems. Celerra uses an explicit deny rule for LUN access so all of the LUNs created on the Celerra must be masked to the intended systems using the iscsi Qualified Name (IQN) before they can be used. In the example configuration, the LUNs are mapped to different servers based upon the role of that system. The IT data center contains a single ESX server called vdi-esx5. The IQN for that server is iqn com.vmware:vdi-esx5. As illustrated in Figure 5, this server has been presented with three iscsi LUNs for the Infrastructure, Swap, and Virtual Desktop Datastores. The masking of devices in this environment is described in Table 1. Table 1. Device masking LUN type Description Masked to Infrastructure Linux Snap Manager, AD Server, DNS iqn com.vmware:vdi-esx5 Virtual desktop Golden virtual machine images Linux Snap Manager Swap Virtual machine swap files All ESX servers iscsi snap LUNs Thin replicas of virtual desktop LUN Production ESX servers vdi-esx1, vdi-esx2,vdi-esx3, vdi-esx4 Virtual Desktop installation and configuration Once the storage configuration has been completed we proceed to establish the baseline desktop images for the environment. The golden image can be established in several ways. The traditional method is to create a VM on one of the ESX servers using the Virtual Center Wizard and install the OS using the manufacturer s distribution media and patch files. Once the baseline image is completed, an ESX VM clone or template of the image should be created to preserve the current state. New VM instances are created from the clone and customized with the applications required for each end-user environment. This final product contains two virtual machine images; one that is a base OS from which you can create additional golden copy images, and the other that is a desktop build image that will be used for deployment after configuration with the sysprep utilities. It s also possible to use the VMware conversion tools or P2V (physical to virtual) to import an existing desktop into the ESX environment. A third option would be to make a copy or clone of an existing system and modify that to suit the needs of the user community. Note: Once the source system has been completed it is strongly recommended that you make a clone or template of the image and store it in the Infrastructure Datastore. For Windows-based systems we can aid in the deployment process using the Windows setup and sysprep utilities that are part of the Windows tools CD. For Windows XP, for example, we would: Complete the system installation and customization process Clone the VM using VirtualCenter or the VMFS volume from the storage array Install the Windows Deployment tools (for an example see Once the system preparation has been completed, perform a virtual machine migration from the staging VMFS Datastore called Infrastructure to the Celerra iscsi LUN (Virtual Desktops), which will be the source of our replication system. Best Practices Planning 13

14 iscsi snap management The Snap Manager is a central component in rapid deployment of virtual machine images. iscsi snap creation and management for the Celerra IP storage system is achieved using a Linux virtual machine that issues secure network commands to the Celerra iscsi target(s). The Linux Snap Manager VM uses a utility called cbm_iscsi to issue LUN management commands to the Celerra iscsi target. The device being snapped is the LUN that constitutes the Virtual Desktop s Datastore. The LUN contains a VMFS formatted file system and the golden copies of the virtual machines that were established in the previous step of the deployment process. The iscsi snap management provided through the Linux-based cbm_iscsi utility offers the control necessary to orchestrate the creation and assignment of the snap LUNs to the ESX server environment. The Celerra iscsi replica management utility is part of a software package that also includes the option to create fully provisioned clones. The software uses an authenticated session between the Linux host and the iscsi target to issue SCSI commands. Configuration of session security requires the creation of a Data Mover user account and CHAP secret configuration on the Linux host prior to the snapshot utility s use. The basic syntax for cbm_iscsi is: cbm_iscsi -snap /dev/sdb create This host must have an iscsi session established with the Celerra iscsi target in order to complete this task. The masking of iscsi LUNs must include each of the ESX servers that are part of the cluster as well as the Linux Snap Manager server. After all of the snaps have been created the promote option can be used to promote the LUNs to the ESX cluster in the production environment cbm_iscsi s /dev/sdb p ESX integration Once the snaps have been created and promoted, the Linux Snap Manager system can issue commands to the ESX environment to perform the following tasks Rescan the iscsi bus and host bus adapters Import the new volumes into the volume tables Identify and import the virtual machines The Linux API utility was used to present the set of snap volumes to each of the servers in the ESX environment. After the devices are masked, the ESX server is able to identify the devices and identify the virtual machines that exist within each snapped volume. Using the command line interface to the ESX server, via the Linux management VM, a trusted command can be executed triggering each server to import the VMs into the environment and establishing a pool of virtual machines. If the systems represent different organizations, the Virtual Machine Name can be modified to identify its role in the organization. In the example used for this white paper the virtual machines are broken into two core groups: one for sales, and the other for service. The VM names thus provide key filters that can be used to create the Virtual Desktop Manager policies. At the completion of these steps the ESX production environment will contain a considerable number of virtual machines. In the test configuration we established two virtual machine images, one each for our sales and service users. Both of these images were included in a single datastore and replicated as a single unit 125 times. At the end of the process the production environment is populated with a total of 250 Virtual Desktop images that are broken into to logical pools. This is visible from an updated topology map that is illustrated Best Practices Planning 14

15 in Figure 6. The Virtual Desktop Management software can then be applied to this pool to establish the user access rights, and power policy. In this example a filter could be applied to the major value of the VM names (that is, sales or service). Figure 6. VirtualCenter topology map view of a VDI environment after deployment with Celerra snapshot technology The ESX server configuration does require some modification to facilitate a seamless volume import and Virtual Desktop registration. Using either VirtualCenter or the ESX server command line interface, set the following parameter to allow the snapped device to be accessed by the ESX server: LVM.Enable.Resignature=1 Additionally the system will require a unique VM UUID when the system starts. In order to avoid user interaction when the system starts, add the following line to the server s.vmx configuration file. This will establish a new ESX UUID when the system boots. uuid.action = "create" Swap file configuration As of ESX version 3.5 the option exists to change the location of the swap file. Prior to this release the swap file was stored with the virtual machine configuration files. Moving the swap file location may be beneficial in an environment where there are lots of virtual machines sharing a single VMFS Datastore. This capability could offload the I/O to a separate disk device and improve the overall performance of the environment. Use ESX and storage performance tools to monitor the disk volumes and determine when it may be necessary to modify the swap configuration by adding additional swap datastores. Figure 7 shows how you would set the swap file to use a separate datastore. Best Practices Planning 15

16 Figure 7. VirtualCenter swap file configuration for a VDI production environment Another key recommendation when using IP storage to support the ESX environment is the use of NIC teaming with load balancing. NIC teaming combined with Celerra advanced network settings provides for multiple I/O paths to the iscsi targets supporting the Virtual Desktop Infrastructure environment. It is strongly recommended that you employ these advanced features in your environment to achieve the optimal performance results. Figure 8 illustrates the VirtualCenter configuration interface for setting network load balancing on the vmkernel interface of the ESX server. Figure 8. VirtualCenter network load-balancing configuration Celerra network considerations Since this is a networked storage system, it is important to ensure all network interfaces are used to distribute the I/O the ESX server requests. Celerra provides advanced network options such as LACP, Ether Best Practices Planning 16

17 Channel, and Failsafe Networking to accommodate this need. Celerra provides several connectivity options for session distribution that, when combined with the ESX load-balancing options, will improve the overall performance of the network protocols. Each iscsi target within the environment is presented through a network portal. A network portal is a component of the iscsi architecture that has a TCP/IP network address and may be used by an iscsi node (vmkernel interface) for connections within one of its iscsi sessions. Celerra provides the ability to assign network portals to any of the physical or logical network interfaces on the Data Mover. A best practice would be to ensure that you create multiple iscsi targets for the VDI environment, and associate each target with a different network portal distributing the iscsi sessions across all of the logical interfaces. The Celerra Management interface provides an option to modify the Data Mover parameters. By default the Celerra iscsi target will respond to the iscsi initiator sendtargets request with all targets that are configured on that network portal. In the case of VDI, we don t necessarily want the Linux Snap server to see all of the targets. Enabling the iscsi SendTargets parameter will return only the list of targets for which the host has been explicitly granted access to a LUN. Note: Set the iscsi.sendtargets parameter to 1 System power up The Virtual Desktop Management software provides several options, including power management for Virtual Desktop environments. A useful option when defining the Virtual Desktop policies is to enable the power saving options for the VDM. It provides both power saving and resource conservation benefits for the VDI environment. As the system is started for the first time the Windows system will trigger the setup utility. Sysprep is provided as a set of windows tools that allow you to prepare an image for distribution or deployment. When a system is started it will run the setup utility and apply the predefined settings to the image within the environment. In VDI some settings would include the network configuration. Since this system is going into an environment where Virtual Desktop is a commodity, IP address assignment will be randomly assigned using a DHCP server. Additional settings would include the Active Domain information and how a hostname will be assigned to the system. Since the solution uses Windows Active Directory for user credentials, VDI can take advantage of another key value from Celerra, which is, the NAS file sharing capabilities and home directory capability, needed for persistent storage in non-persistent virtual machine pools. In order to use home directories in the VDI environment, the Celerra must have a CIFS server, at least one CIFS share configured within Active Directory, and folder redirection enabled for the My documents object. In the following example the CIFS server name is \\cifs. The shared folder is named home_dir and we are going to create an explicit home dir mapping for an Active Directory domain user account through the Properties page of the selected user, as shown in Figure 9. Best Practices Planning 17

18 Figure 9. Active Directory user properties and GPO interface Alternatively the setting can be applied for all users with the Folder redirection GPO for My Documents and can be set following the Windows Manager path: Group Policy Object > User Configuration > Windows Settings > Folder Redirection > My Documents Figure 10. Active Directory and GPO editor interface This feature ensures that no matter which VM a user logs in to, their home directory and any additional mappings will be available to store and access persistent data. Best Practices Planning 18

19 Snap image revocation Earlier the concept of how to create and promote a snap was covered for the purposes of provisioning virtual machines. The Celerra iscsi snap architecture allows the administrative user to also demote the snap, in essence discarding any changes that have been made to the system and reverting the image to its initial snap state. For example if a system has been promoted and powered on and accessed by a particular user, it might be desirable to reset or demote the snap image in order to clear any contents that were created during that user s session. Snap demotion is also part of the update process. In order to roll out a new or updated image of the desktop, we would simply invoke the snap demote command, delete the snap, create and promote a new image, and log in to the system with the updated version. This entire process can be accomplished in a matter of minutes using Celerra iscsi snap technology. So in these two brief examples we see how snaps can be used in a security conscious environment to reset the desktop image between user sessions, and as part of an overall deployment process to refresh the desktop image. Best Practices Planning 19

20 Conclusion Throughout this paper we have highlighted the benefits that Virtual Desktop Infrastructure can provide within your environment. There are several areas of benefit that can be realized through the migration to a centralized desktop model. They include the following: Improved system reliability Increased security Faster time to deployment Reduced restore and service times. Improved desktop image management. We have illustrated how the value provided through the VDI framework can be demonstrably improved through the addition of a Celerra IP storage system. Celerra offers functionality to accelerate the deployment process for initial implementations as well as periodic updates to operating system patches, virus signature files, applications, and any other type of image customization affecting all of your desktop users. Celerra and VDI offer a single image management solution for increased reliability and recovery of the desktop images in your environment. Reliability is achieved through the knowledge that each desktop image contains the same operating system version, patch version, and application revision levels. Integration testing can be completed using a single golden copy in a separate ESX data center and once completed used as the source version to update all of the target systems. Additional support from Celerra is provided through multiprotocol storage for user home directories and persistent network storage devices using RAID protected enterprise storage. This paper s aim was to illustrate how easy it is to tie an enterprise class storage system together with the leader in virtualization technology to provide a fast and efficient desktop deployment solution. With a few generally available command line utilities that exist within Celerra, ESX Server, and Virtual Desktop Manager, we can establish a Virtual Desktop environment comprised of hundreds of virtual machines in a matter of minutes. References The following documents can be found on EMC.com or Powerlink, EMC s password-protected customerand partner-only extranet, unless noted: Configuring iscsi Targets on Celerra technical module (Powerlink only) EMC Celerra Virtual Provisioned Storage white paper Using EMC Celerra IP Storage with VMware Infrastructure 3 white paper The following can be found on VMware.com: Virtual Desktop Infrastructure white paper Virtual Desktop Infrastructure Server Sizing Guide Best Practices Planning 20