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1 Clustered Open iscsi SANs 1 SAN/iQ : Enabling Technology for Effective VMware Deployments Technical White Paper CLUSTERED OPEN ISCSI SANS

2 Clustered Open iscsi SANs 2 This white paper describes how SAN/iQ technology from LeftHand Networks can help you to deploy VMware Infrastructure 3 software more effectively through SAN/iQ technology s volume snapshot, volume migration, and high-availability features. Copyright 2007 LeftHand Networks Inc. All rights reserved. LeftHand Networks, the LeftHand Networks Logo, and SAN/iQ are registered trademarks of LeftHand Networks, Inc. VMware and the VMware boxes logo are a registered trademarks of VMware, Inc. INTRODUCTION IT organizations are recognizing the benefits of virtualizing their datacenters, and many of them are enabling server virtualization with VMware Infrastructure 3. VMware Infrastructure 3 software allows IT organizations to manage their server infrastructure as a single pool of resources on which applications can be deployed and then moved dynamically from server to server as workload and business requirements dictate (Figure 1). Some of VMware Infrastructure 3 software s features, including high availability VMotion, require the use of a SAN. Figure 1: VMware Infrastructure 3 virtualizes an IT organization s server infrastructure. With applications and their host operating systems encapsulated into individual virtual machines, they are no longer bound to a specific physical server. IT organizations can finally break free of the legacy of silo-oriented application architectures that limit sharing and require each application domain to run on its own dedicated set of underutilized hardware. By virtualizing and consolidating their applications onto a smaller number of more highly utilized physical servers, organizations can re-claim valuable datacenter space and reduce their power and cooling requirements. With applications and servers decoupled, they are free to allocate varying resources to applications as their workloads change and as their business priorities dictate. Rolling out new applications does not always require deploying new servers because they can draw on the power of a uniform, shared infrastructure. VMware Infrastructure 3 offers compelling features for IT organizations concerned with resource management, high availability, and disaster recovery. VMware VMotion enables running virtual machines to move from server to server. This allows administrators to balance workloads and performance to match user demands, and even to vacate a server in order to take it offline for maintenance. VMware HA monitors the state of running virtual machines and, in the event of a server failure, restarts the virtual machines on alternate servers. A Choice of SAN Technologies Features such as VMotion and VMware HA require continuous access to the underlying storage from multiple servers, which requires implementing a SAN. VMware allows customers to choose between traditional Fibre Channelbased SANs, network-attached storage, and iscsi SANs. There are several advantages to using iscsi SANs implemented with SAN/iQ technology from LeftHand Networks. LeftHand SAN/iQ technology-based iscsi SANs use simple and cost-effective technology that helps IT organizations save on the cost of implementing storage-specific networks with specialty host bus adaptors, switches, and optical interconnects. In addition, LeftHand SAN/iQ provides specific features that virtualize

3 Clustered Open iscsi SANs 3 storage in ways that are analogous how VMware virtualizes server resources (Figure 2). LeftHand SAN/iQ products use standard IP networking, a technology that every IT organization understands and has existing infrastructure to support. Ethernet networks are everywhere, so equipment to support them is priced low by a highly competitive marketplace. This significantly reduces the cost of iscsi SANs. SAN/iQ technology allows IT organizations to add storage as needed, incorporating new modules in its clusters dynamically and transparently. Figure 2: LeftHand SAN/iQ technology virtualizes storage infrastructure with logical volumes supported by storage clusters. Capabilities Analogous to VMware LeftHand SAN/iQ technology is certified to work with VMware, and is listed on VMware s Hardware Compatibility List (HCL). In addition, several SAN/iQ technology features complement VMware s virtualization capabilities by performing functions in storage that are analogous to those VMware performs in servers: Organizations can clone storage volumes just as VMware clones virtual machines. But by cloning at the storage level, duplicate volumes can be created through snapshot mechanisms and mounted for read/write activity in an instant and with minimal use of storage. Just as VMotion can move running virtual machines from server to server, LeftHand SAN/iQ technology can move a virtual machine s virtual disks from storage cluster to storage cluster without taking down or reconfiguring the virtual machine. This allows logical volumes to be moved to different storage clusters to balance storage capacity and workloads, and it can be used to completely offload a cluster so that it can be taken out of service for upgrade or maintenance. SAN/iQ technology allows IT organizations to treat their storage infrastructure as a single, continuously available, virtual pool of storage. You even can distribute the pool of storage among multiple locations, ensuring that SAN/iQ technology s built-in replication function maintains identical copies in each of two locations. VMware can re-start failed virtual machines in alternate locations even through the failure of a datacenter that takes one site s servers and storage offline. LEFTHAND SAN/IQ TECHNOLOGY FUNDAMENTALS LeftHand Networks SAN/iQ technology uses standard iscsi protocols and standard IP networking techniques to deliver storage that is open, clustered, and compatible with VMware. This section discusses some of the technology behind SAN/iQ software and how it can best be leveraged with VMware products. Standard, Compatible iscsi Initiators LeftHand Networks SAN/iQ technology supports standard iscsi protocols, providing compatibility with virtually any operating system having an iscsi initiator. Indeed, the fact that LeftHand implements standard, open iscsi protocols allows servers to utilize SAN/iQ technology-based storage without having to install any third-party server software. The operating system s iscsi initiator acts as if it controls a physical SCSI device, making the underlying IP network invisible to applications. When the iscsi initiator is initialized, it is configured with a set of iscsi Qualified Names (IQNs). These IQNs map to a set of IP addresses where the initiator can discover which Logical Unit Numbers (LUNs), or logical volumes are available to it. This mapping function is important because it gives flexibility in where logical volumes are stored on the network.

4 Clustered Open iscsi SANs 4 Best Practices The use of standard, compatible iscsi initiators allows servers running VMware to access LeftHand iscsi SANs through initiators in the host operating system, in one or more guest operating systems, or both (Figure 3) If your guest operating systems boot from virtual disks stored in iscsi storage, they must be accessed through the iscsi initiator in VMware ESX Server or through an iscsi HBA. These disks appear in virtual machines as local SCSI drives. Additional data that you wish to manage independently of VMware can be accessed from iscsi initiators in the guest operating systems. This allows you to overcome a limit of 64 iscsi targets that VMware ESX Server currently imposes, and it also allows you to manage large amounts of application-specific data (such as a database) directly through LeftHand s management interfaces. High Availability Through Network RAID SAN/iQ technology-based storage implements network RAID across a cluster of storage Figure 3: Virtual disks must be accessed through the ESX Server iscsi initiator, while raw volumes can be accessed by ESX Server or its guest operating systems. modules. The cluster stripes data across storage modules in the cluster, and replicates blocks as dictated by each volume s replication level. You can scale a SAN/iQ technologypowered storage cluster simply by adding a new network storage module. Internal to the cluster, SAN/iQ technology re-stripes the data to incorporate the new device. This is analogous to adding a new server to a resource pool in VMware infrastructure 3. You can add a server and VMware Dynamic Resource Scheduling (DRS) will re-balance the set of virtual machines it manages across the newly enlarged Virtual Infrastructure 3 cluster. Storage clusters area available to the server s iscsi initiator through a Virtual IP address (VIP) The use of a VIP virtualizes the cluster so that it can balance both the workload and the storage of specific blocks internally to the cluster and be transparent to the servers that access it. If the storage module answering the VIP fails, the cluster will continue to respond to requests from one or more alternate servers in the cluster. As data is written to the cluster, the single storage module receiving a data block from the server replicates the block to additional storage modules, in real time, according to logical volume s network RAID level. Regardless of network RAID level, blocks are striped across the cluster for high performance (Figure 4). The result is that the larger the cluster, the higher its performance. Each storage module s disks are typically combined as a RAID 5 volume internally, and the high availability of the cluster increases with the replication level assigned to each logical volume. Everyone knows that RAID allows highly available storage to be created from a set of inexpensive disk drives. Any one drive can fail in a RAID array and the data will continuously be available. Similarly, with SAN/iQ technologybased storage clusters, any one storage module, or even part of the cluster in a different location can fail, and data will continue to be available. The Open iscsi SAN Approach What makes SAN/iQ technology such a superior technology to traditional SAN implementations is that it doesn t use expensive, purpose-built hardware. SAN/iQ is an open software technology because its storage modules run on enterpriseclass x86-architecture hardware where the cost is driven out by the forces of a competitive marketplace. It then increases the reliability over that of a single server by replicating data across storage modules. Unlike traditional SAN hardware, which typically has a month refresh cycle, SAN/iQ technology can ride on

5 Clustered Open iscsi SANs Figure 4. Blocks are striped across the storage modules in a storage cluster for performance, while they are replicated as dictated by the logical volume s properties (replication level of 2 in this example). the faster server innovation cycle of 9-12 months, making an organization s storage on par with its server technology. This solution is also more flexible than traditional approaches because it allows IT organizations to support application ability through storage policies that can be configured on a highly granular basis. The Network RAID level is a property of the logical volume, not the storage cluster. Network RAID, including block replication levels, can be assigned to each logical volume based on the requirements of the data that it stores. Replication levels can be changed, and the cluster will automatically accommodate, if those requirements change. Each storage module in the cluster runs SAN/iQ software on one of LeftHand Networks off-theshelf products (such as the NSM 160 or NSM 260 systems), or on a new or repurposed HP DL380 G4, HP DL320s, or IBM x3650 server. A single storage cluster does not require a uniform set of hardware, and customers can match models and makes of storage modules. Storage clusters typically begin with three modules,and can scale by adding modules to the cluster. As more storage modules are added, the cluster can automatically re-balance its workload without interrupting its ability to service requests. VMware And SAN/iQ Storage Clusters Storage is managed on any device through LUNs, or logical volumes. VMware provides access to virtual disks through a virtual SCSI device that is provided by each virtual machine to its guest operating system. This simplifies the relationship between applications and storage. It also allows guest operating systems to access their virtual disks through the same interface regardless of the underlying hardware platform. Whether a virtual disk is stored on direct-attached, network-attached, or SANattached storage, the guest OS views a virtual disk through a SCSI device initiator. Virtual disks can be stored as flat files in which each block of the flat file simulates a block on a real disk drive. Many of these flat files are typically stored in a single logical volume. Virtual disks also can be stored as raw volumes, where a virtual disk is assigned its own logical volume and the guest operating system manipulates blocks directly. Best Practices The value-added features that SAN/iQ technology-powered storage clusters provide to VMware ESX Server are available on a logical volume basis. Replication, for example, is performed on a logical volume basis. Snapshots used for backups are taken of a logical volume. And features like volume cloning are also provided on a logical volume basis. Because of this, you should take care to store related virtual disks together on the same logical volume. If, for example, you expect to replicate a Web server environment, consider putting all of its related virtual disks into one logical volume that can be replicated as a unit. If, for example, you wish to back up an entire application stack, consider putting all of the related virtual disks into a single logical volume so that a single snapshot can capture all of the application OS, software, and data at once. Large amounts of data, for example an enterprise database, may best be stored in raw volumes where each block can be accessed through only one layer of indirection rather than the two layers of indirection imposed by storing a virtual disk as a flat file in a containing filesystem. Storing data such as this in a raw volume allows more flexibility because it can be attached to a virtual machine as a virtual disk,

6 Clustered Open iscsi SANs 6 or it can be accessed directly from a guest desktop environments and deploy new Leveraging LeftHand s Snapshot Mechanism The workflow for cloning a virtual machine operating system through its own iscsi initiator. virtual PCs for users based on consistent, using LeftHand s snapshot mechanism is ACCELERATING VM CLONING WITH SAN/IQ SNAPSHOTS VMware Infrastructure 3 makes it easy to create and provision new virtual machines based on tested configurations that help to reduce the cost of maintaining a unique environment for each user. Cloning virtual machines through VMware VirtualCenter is a straightforward process that When virtual machines have large amounts of data, are to be copied numerous times, and are expected to have short lifespan, a better solution is to use volume cloning in the storage cluster itself. LeftHand SAN/iQ technology includes a unique snapshot mechanism that straightforward: Use the SAN/iQ administrator interface to create a snapshot of the logical volume containing the virtual disk files you need to clone. existing ones, a process referred to as cloning. copies an existing virtual machine s virtual supports multiple snapshots of the same logical Cloning adds to an IT organization s flexibility, disks, creates a new virtual machine based on volume, each one of which can be mounted for responsiveness, and efficiency by allowing the existing one s characteristics, and attaches read/write operation (Figure 5). whole new environments to be created without the copied virtual disks to the new virtual being encumbered by physical hardware. machine. This is an easy way to create new When you use LeftHand s snapshot mechanism environments for long-term use, but there are when creating a new virtual machine, you can Organizations can use cloning in a number two problems using VMware virtual machine create new virtual disks instantaneously, and of ways. They can create and deploy a set of cloning for short-lived virtual machines: you only consume physical storage for the disk temporary Web servers to manage performance blocks that are modified (plus a and capacity in response to spikes in workloads. The cloning process creates a new copy of small amount of metadata). Using They can clone existing, mission-critical each virtual disk, which takes a considerable this approach, you reduce staff applications and use the copies to test new amount of time when each virtual disk is tens time, increase responsiveness, patches or configurations before deploying of gigabytes in size. and make more efficient use of them on production systems, reducing risk. your storage resources. Developers can create virtual laboratories Each new virtual disk uses physical with as many virtual machines as they need to develop and test their software. IT organizations can create golden master versions of their storage, depleting storage resources for data that, for the most part, won t vary from its original source. Figure 5: LeftHand s volume cloning capability allows VMware to use volume snapshots that can be modified without affecting the original source.

7 Clustered Open iscsi SANs 7 In VMware VirtualCenter, click Rescan to locate the new storage. The resignaturing option must be turned on in VMware ESX Server. Add the new virtual disks to Virtual Infrastructure 3 software s inventory. Stacks of Snapshots LeftHand SAN/iQ technology allows you to create a stack of snapshots based on a single original volume, where each snapshot is dependent on the prior snapshot (Figure 6). When you create a snapshot, SAN/iQ software also creates an independent write area for the snapshot. The write area holds the collection of blocks that are modified from the original, and the snapshot s metadata points back to the original, unmodified blocks. With the SAN/iQ user interface, you can delete the write area, instantly rolling back to the original snapshot state. You also can create a new write area, allowing the rolled back volume to be modified once again. The ability to have several snapshots of the same logical volume, and to allow each one to be independently read and written, allows you to have many virtual machines that start with the same golden master image, but consume only a minimal amount of physical storage space. Best Practices The best way to use SAN/iQ technology snapshots is to perform them using the SAN/iQ user interface, and add a comment for each snapshot volume that indicates its use. This way, administrators can evaluate whether they really can delete a snapshot by tracing it back to the virtual machine that uses it. Avoid using scheduled snapshots to clone volumes to be used by virtual machines. Scheduled snapshots, such as those used for backups, are created on a schedule, and can also be deleted on a schedule. You don t want to risk having a volume that is in use by a VMware virtual machine be Figure 6: LeftHand Networks deleted while it is SAN/iQ technology supports a chain in use because of of snapshots, each one dependent on the previous one, and each one a schedule. with its own unique write area. VMOTION FOR STORAGE: SAN/IQ VOLUME MIGRATION VMware VMotion allows IT organizations to move running virtual machines from server to server without interrupting the services they provide. This allows IT organizations to Original Volume Snapshot 1 Snapshot 2 Snapshot 3 Separate Write Areas dynamically change the mapping of virtual machines to servers, and it is the technology on which VMware Dynamic Resource Scheduling (DRS) is based. VMotion supports: Managing performance by moving virtual machines with high resource demands to less-utilized servers Re-balancing workloads after adding one or more servers to a resource pool Matching virtual machines to server capabilities as workloads change Moving volumes between physically different clusters, such as from SAS to SATA disk types, or between storage modules configured with RAID 0 to RAID 5. Vacating a server for maintenance or upgrades IT organizations also need to be able to move logical volumes between storage systems for all of the same reasons, but unfortunately, traditional Fibre Channel SANs fall short in the capabilities they provide. Moving a logical

8 Clustered Open iscsi SANs 8 volume typically requires quiescing the data by shutting down the corresponding virtual machines, performing the copy using remote replication or remote copying software (often an additional-cost feature), reconfiguring the virtual machines to access the relocated logical volume by its new identifier, and finally restarting the virtual machines. This is a tricky process, prone to error, and can result in significant down time depending on the amount of data copied. Live, Online, and Immediate Migration LeftHand SAN/iQ technology allows IT organizations to move live logical volumes between storage clusters without interrupting the virtual machines using them, and without them even knowing that their storage has been moved. This enables IT organizations to enjoy the same benefits in storage as they do when using VMotion with their servers. LeftHand SAN/iQ volume migration supports: Managing performance by moving logical volumes with high I/O demands to less-utilized clusters Re-balancing storage workloads after adding new storage clusters Matching logical volumes to the performance characteristics of different storage clusters Moving logical volumes between geographically separated clusters Vacating a cluster for maintenance or upgrades VMotion and volume migration are analogous; the former moves virtual machines between servers, and the latter moves logical volumes between storage clusters. These two features are independent and transparent to each other. A storage cluster does not know when a virtual machine has been moved, and a virtual machine does not know when its virtual disks have been moved (Figure 7). The IP address of the virtual machine remains the same when it moves, and the logical unit number for a logical volume remains the same when it moves, as well. Behind The Scenes When two or more clusters are in the same SAN/iQ management group, moving logical volumes between them is as simple as editing the volume s properties so that it has a different cluster as its owner. SAN/iQ software first moves the volume s metadata, and then asynchronously moves the volume s data blocks. The servers or virtual machines accessing the logical volume continue to make requests to the original storage cluster. The original cluster acts as a proxy, passing requests on to the new cluster depending on which cluster currently owns the block being Figure 7: Just as VMotion moves running servers between servers, SAN/iQ technology migrates live volumes between clusters. requested. If the original cluster is taken out of service, or if the server accessing the storage is rebooted, the server s iscsi initiator will discover the migrated volume by finding the same IQN on a new cluster. DISASTER RECOVERY WITH UNINTERRUPTIBLE STORAGE VMware HA provides cost-effective high availability for applications that do not have

9 Clustered Open iscsi SANs 9 their own built-in HA mechanisms, providing organizations with a base level of disaster recovery capability regardless of how simple or complex the application. VMware HA continuously monitors virtual machine health and automatically re-starts failed virtual machines on secondary servers in the event of a failure. By locating parts of a VMware server cluster in different datacenters on the same campus, or even in different closets in the same building, IT organizations can withstand a disaster that makes one of the two sites unavailable. For VMware HA to work with no human intervention, it requires continuous access to every virtual machine s virtual disks. Traditional, Fibre Channel-based SANs are typically built with redundant components to achieve high availability levels. To survive the loss of an entire datacenter, however, they typically use remote replication software that adds to the cost of the SAN. An issue with some with remote replication solutions is that a replicated logical volume has a different unique logical unit number than the original. If an entire datacenter fails, VMware HA can restart virtual machines in the alternate location, but the server will fail to find the replicated storage because it has a different logical unit number. Now human intervention is required to reconfigure each server and virtual machine to access the appropriate LUN. Then, when the original datacenter comes back online, a slow, manual process of resynchronizing the replicated volumes with their original versions must be completed before virtual machines can be moved back to their original servers. Storage Availability to Match VMware HA Requirements LeftHand s SAN/iQ technology can provide the continuous access to storage that VMware HA requires simply by splitting a storage cluster between the two locations and providing a high-speed link between locations. The cluster provides continuous availability so long as an even number of storage modules is configured in the cluster, the logical volume data is replicated, and even-numbered modules are in one location while odd-numbered modules are in the alternate location. This configuration ensures that every block stored in a logical volume is replicated between the two locations. The cluster automatically responds to the failure of some of its servers with the remaining servers responding to requests, regardless of whether the cluster is located entirely in one location or split between two locations. Consider a simplified example where two datacenters each host one physical server, and both are members of the same VMware HA cluster (Figure 8). Datacenter 1 runs virtual machines A and B, and Datacenter 2 runs virtual machines C and D. The virtual disks for each virtual machine are stored in a single logical volume. As long as the logical volume s properties specify a Network RAID replication level of 2, both locations will have an identical set of blocks because every block will be replicated across even and odd storage modules. If the power in Datacenter 1 fails, VMware HA will re-start virtual machines A and B on the sever in Datacenter 2, booting from virtual disks A and B. Unknown to VMware ESX Server, the SAN/iQ technology-powered storage cluster recognized the failure of the modules located in Datacenter 1, and it may have moved the ownership of the cluster s VIP from a storage module in Datacenter 1 to a module in Datacenter 2. The failure of an entire datacenter is handled just as the failure of one or more servers in a cluster is handled. Access to storage is never interrupted, and the virtual machines re-started by VMware HA simply access their virtual volumes just as they did in Datacenter 1. The cluster s IP address and the volume s LUN are unchanged. Using a distributed storage cluster allows failover to execute seamlessly. Unlike failover using SANs and remote replication, failback is automatic and seamless. When the power is restored to Datacenter 1, VMware can automatically re-balance the workload, using VMotion to move virtual machines A and B back to the server in Datacenter 1. The modules in Datacenter 2 continue to respond to storage

10 Clustered Open iscsi SANs 10 requests. When the modules in Datacenter 1 come back online, the cluster recognizes that they have out-of-date data blocks, and the cluster internally, and transparently, reconciles the differences by copying the changed blocks back from Datacenter 2 to Datacenter 1, restoring the desired replication level of 2. VMware Virtual Disks VMware Virtual Disks Datacenter 1 Datacenter 1 The beauty of this solution is that failover and failback is automatic, and requires no human intervention. Combined with VMware HA, this solution provides both a server and a storage disaster-recovery strategy for organizations of all sizes, and for even the simplest of applications. Small businesses can distribute VMware Virtual Disks Figure 8: A SAN/iQ technology-powered storage cluster with an even number of storage modules can provide continuous availability to VMware HA even across the loss of an entire datacenter. their storage clusters across multiple closets in the same building, while medium and large businesses can distribute their storage clusters across multiple datacenters on a campus. Best Practices This solution works when the following requirements are met: The storage cluster is split between two locations connected with a minimum of 1 Gbps bandwidth and less than 2 ms. latency. Storage blocks are replicated between even and odd storage modules synchronously, requiring a high-speed network connection between all modules. Likewise, requests coming into one half of the cluster may be load balanced to the other half of the cluster, so network performance between cluster halves is important. Either a Virtual Manager or another storage module in a neutral location is required. The Virtual Manager allow for manual failover control while another storage module provides automation of failover. The storage cluster must operate on the same IP subnet, as it maintains one and only one VIP for incoming requests. An even number of storage modules must be deployed, with even-numbered storage modules in one location and odd-numbered storage modules in the second location. Logical volumes participating in the disaster-recovery plan must have their replication level set to 2 so that each block is stored in both locations. Large companies can extend this solution to multiple datacenters. For example, a cluster can be distributed across three locations, with storage modules deployed in threes. Storage modules numbered in multiples of 1, 2, and 3 are stored in their respective locations.

11 Clustered Open iscsi SANs 11 Likewise, smaller companies can achieve some disaster-recovery capability by locating cluster halves in different datacenters, offices, or even closets in the same building. The value of the redundancy can be increased by powering the two halves of the cluster from different circuits or building power feeds, and cooling them from different cooling systems, one cause of datacenter failures that is often overlooked. BETTER BY DESIGN This white paper has focused on three specific capabilities of VMware Infrastructure 3 that LeftHand Networks SAN/iQ technology complements in storage. You can use SAN/iQ technology to speed virtual machine cloning by replicating logical volumes using SAN/iQ software s unique snapshot mechanism. You can move live storage between storage clusters to optimize performance, capacity, or for administrative or business reasons without interrupting the virtual machines that access the storage indeed without them even knowing. SAN/iQ technology lets you create distributed storage clusters that automatically handle failover and fallback so that VMware HA can operate with no human intervention. Finally, using SAN/iQ through your operating systems built-in iscsi initiators allows you to connect logical volumes to VMware ESX server or to individual virtual machines, giving you control over how storage is configured and accessed. With all of the features that directly benefit IT organizations running VMware Infrastructure 3, it may be easy to overlook the fundamental features of LeftHand Networks SAN/iQ technology that makes it a superior solution for any datacenter environment. SAN/iQ technology delivers an open, network-centric, distributed, and clustered storage solution that has inherent benefits. It is highly scalable, allowing IT organizations to add storage modules as they are needed, with SAN/iQ technology incorporating the new capacity automatically, seamlessly and with no downtime. It is a highly available solution that uses Network RAID to achieve high availability levels with the cost-effectiveness off off-the-shelf, state-of-the-art, x86 server technology. SAN/iQ technology-based storage delivers a high level of reliability, allowing IT organizations to dial in the desired level of protection, most often on a per-volume basis. SAN/iQ technology provides multiple layers of protection including RAID on the individual storage modules, Network RAID, snapshots, and remote copy. SAN/iQ technology delivers high performance without the high price by leveraging available resources from multiple spindles in each storage module to multiple, aggregated network links. Finally, SAN/iQ technology is easy to use. Using its intuitive graphical user interface, customers can configure and manage their storage while allowing the storage clusters themselves to implement specific directives, from creating snapshots that support new virtual machines, to incorporating new storage modules in a cluster. LeftHand Networks support for VMware, combined with the overall benefits of using open, network-centric, distributed, and clustered storage solutions make it a natural choice for any IT organization running VMware Infrastructure 3 software.