NON-STOP, LIGHTNING-FAST, WASTE-FREE SANs

SALES REFERENCE CARDTECHNICAL FEATURE DESCRIPTIONS

SANmelody™ and SANsymphony™

Technical Highlights

Descriptions and illustrations of DataCore’s advanced storage virtualization software.

Rarely does a single storage device fit all of an organization’s long term needs. Aging hardware, lack of backward compatibility and product

obsolescence lead to natural variations in storage infrastructures, even within the same brand and product line. The systemic and financial impact of these variations become readily apparent each time your storage environment changes; be it a failure, repair, upgrade, or expansion. Every modification progressively slows down, interrupts or endangers your IT operations. Although a wholesale replacement could bring temporary relief, it is merely an expensive way to restart the vicious cycle. Over the past 10 years DataCore has developed sophisticated storage virtualization technologies to overcome device-specific differences and limitations so that you may experience non-stop, lightning-fast, waste-free SANs despite continuous changes in the makeup of your storage pool. The functions are described in the following pages. You’ll also find comparisons between the SANmelody and SANsymphony products to assist you in determining which solution best fit your storage infrastructure needs.1

Topic

Virtualization Technology

Features at a Glance

Heterogeneous Storage

Capacity Allocation

Performance

High-Availability

Migrations and Upgrades

Backup and Restore

Offsite Disaster Recovery

Management

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2

3

4

5

6

8

9

10

12

14

SAN-wide Functions Work Across Unlike and Incompatible Storage Devices

1For use cases, benefits, supported environments and prerequisites, please refer to the SANmelody and SANsymphony product datasheets.

2

VIRTUALIZATION TECHNOLOGY

DataCore uses software to transform imperfect storage

hardware devices into ideally behaved disks; i.e., “virtual disks” that have plenty of capacity, run fast, are easily shared, never age and are always accessible. This emulation overcomes differences, limitations and flaws inherent in all real devices, whether they are basic disk drives or top-of-the-line disk arrays.

The software harnesses the power of dedicated x86/x64

Windows servers to speed up disk response, execute replication, data protection, and other advanced functions, while generally managing the allocation of the virtual storage pool. The servers effectively turn into locked down, “universal storage controllers” and cease to be general purpose machines. They may be chosen from your preferred manufacturer and sized to your specific I/O requirements. Configuring the DataCore nodes for N+1 redundancy eliminates single points of failure.

This allows one node and its resources to be taken out-of-service for repairs, upgrades, expansion and replacement while another takes over its duties without disruption. Unlike array- or appliance-based firmware, there’s no discarded investment and no upheaval in your storage practice when you transition to the next hardware platform. It’s as portable as moving your database server and its licenses to a faster machine. You can run DataCore software on physical and virtual machines for the widest choice of platforms and compatibility.Up to 1 TB of SAN-wide cache per DataCore node can be configured for unprecedented, lightning-fast response from modest back-end disks.

The software pools free space from any disks internal to the

nodes and any direct-attached or SAN-based external arrays. The system administrator carves out virtual disks from this resource pool according to the specific capacity, availability and performance needs of your computers.

For example, some groups of virtual disks may be defined to be cached, locally mirrored, remotely replicated and thinly provisioned. In the background, the DataCore software will tap multiple real devices and the necessary computing and network connections to meet those requirements. The virtual disks are then assigned to specific iSCSI or Fibre Channel ports on the computers needing storage where they appear as conventional disks on a SAN.

DataCore supports storage consumers running any of

the popular operating systems. It is compatible with Windows, MacOS, Linux, NetWare, HP-UX, AIX, and Solaris, but does not depend on host-based agents to provide services. Server and desktop virtualization products from companies like Citrix, Microsoft and VMware depend on DataCore SANs for well behaved, highly-available, shared storage. They realize distinct availability and performance advantages when implementing virtual machine migrations, workload fail-over and dynamic load balancing.

Emulate Ideal Disk Behavior to Overcome Device Differences & Limitations

iSCSI & Fibre Channel SAN

Heterogeneous Storage Pool

“Virtual Disks”

x86/x64 physical or virtual servers

with internal & external storageUltra-high performance

using CPUs & memory as“mega caches”

Storage Consumers

(Clients)

iSCSI & Fibre Channel SAN connections

3

SALES REFERENCE CARD

Small to Midsize SAN Midsize to Large Scale SANs

Which One is Right for You?

Feature SANmelodyTM SANsymphonyTM adds

Virtual Disk Pooling ≤32TB >32TBs into Petabytes, Tiered Storage Classes, SAN Domains

Synchronous Mirroring (High Availability)

High-Availability (HA) Pair

N+1 redundancy, Tertiary mirror, Alternate replication route, Prioritized order of resynchronization

High-speed Caching Included Linear Scaling, QoS control

Load Balancing Included Support for high-end, multi-path arrays

Thin Provisioning Included Choose virtual disk size, serially fill disks, display real-time usage statistics

RAID Striping Included Hot spares automatically replace failed drives

Virtual Disk Migration Included + optional P-V-V migration

Optional pooling of existing disks formatted with Unix & other file systems

Online Snapshot Included Synchronized across groups of virtual disks

Continuous Data Protection (CDP) N/A Optional

Remote Replication (Asynchronous) Included Many-to-many, Group-wide control

Advanced Site Recovery(ASR)

N/A Optional, 1-to-many, many-to-many

Analysis & Reporting via Perfmon + optional package

Extensive built-in choices + optional package super set

Centralized Management Included SAN, Performance, Diagnostics,

Associated objects managed as groups

FEATURES AT A GLANCE

4

Virtual Disk Pooling is the DataCore’s over arching feature responsible for consolidating storage

capacity from like or unlike disk resources. As noted earlier, the pool may encompass a variety of brands and models of disks, effectively creating storage tiers with different price/performance/capacity characteristics. Pooling is fundamental to storage virtualization capability, enabling virtual (or logical) disks to be rapidly created from blocks of space on the physical devices. Using a central administrative interface,

Virtual Disk PoolingConsolidate like or unlike disk resources

Split pool into tiers• Create and assign virtual • disks of desired sizesDefine access rights• Share them among clients• Expand capacity • without downtimeEliminate stranded space•

HETEROGENEOUS STORAGE

these virtual disks can then be assigned to storage consumers throughout the SAN with specific access permissions, possibly shared among different servers, virtual machines or clustered applications. The upper limit on a SANmelody storage pool is 32 Terabytes, whereas SANsymphony scales well into the petabytes. Below you see how a DataCore storage pool can be composed of different brands and models of disks and managed as a central resource to meet the varied needs of applications. Before we exhaust the capacity of some devices in a specific tier, we can add more, possibly using the next generation product from the same supplier or a new brand that offers us the same reliability with more favorable price/performance. And as new storage consumers arrive they can immediately tap into the storage pool via their iSCSI or Fibre Channel SAN connection.

Manage Capacity as a Pool of Disk Space

Tiered SAN

Tier Cost RAS Speed Density Disk Space (Terabytes)

1

2

3

Hi

Med

Low

Hi

Hi

Med

Hi

Med

Low

Low

Med

Hi

W brand P1 model

W brand G2 model

X brand S3 model

W brand P3 model

W brand G5 model

Z brand Q7 model

6 TB

8 TB

11 TB

Used

Used

Used

5

In these tougher economic times, thin provisioning is gets a lot of press and rightly

so. DataCore’s implementation spans any physical devices in the pool that you choose and like its other features, is not dependent on any one host, operating system or hypervisor. There are two parts to thin provisioning. On the one hand, the storage consumer is fooled into thinking that they have very large drives all to themselves. In reality, software only takes up space when it is actually written to. This solves the problem of guessing wrong and wasting space when an application first asks for a lot of capacity even though they may never use it.

Thin ProvisioningAllocate just enough space, just-in-time

Appears to computers as very • large drives (e.g. 2 TB disks)Takes up only space • actually being written toDynamically allocates more • real space when requiredReduces need to resize LUNs•

CAPACITY ALLOCATION

Rather than tie up all that space, we dole out only blocks as needed, just in time. This works out well with virtual machines that like to mount volumes that are much bigger than they actually need. Some refer to it as oversubscription. In the example below, we’ve logically assigned 6 TBs, but the applications have only written to less than ½ TB. When real consumption starts to exhaust our physical space, we alert the administrator to add more. You get to set when the alarm goes off. Once more drives arrive, you instruct the software to add the new capacity to the existing pool to give you more breathing room. All that can happen non-disruptively. Moreover, the additional space could come from completely different equipment given your preferences at the time. DataCore also includes utilities to reclaim space temporarily consumed on thinly provisioned virtual disks and later zeroed out by the client computers.

Waste-Free Space Allocation

Virtual Disk 1

Virtual Disk 3

Virtual Disk 2

2 TB

2 TB

2 TB0

0

0

0 0.4 TB 1 TB

60% Free

Expand as Needed

No Device Dependency

Alert when time to add moreActual

Use

Virtual Allocation =

2.0 TB+ 2.0 TB+ 2.0 TB

___________ 6.0 TB

Takes up only 0.4 TB

Physical Disk Pool

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High-speed caching has long been a potent differentiator for DataCore’s products. If you

have been conditioned by other suppliers to believe that any form of virtualization brings a performance penalty, think again. In the process of virtualizing disks, DataCore software accelerates reads and writes by leveraging the powerful processors and large memories of the x86/X64 servers on which it runs. Up to 1 Terabyte of cache may be configured on a DataCore node enabling it to perform at solid state disk speed without the expense. Caching essentially recognizes I/O patterns to anticipate which blocks to read next into RAM from the back-end disks. That way the next request can be fulfilled quickly from memory at electronic speeds.

High-speed CachingSpeeds up performance

Accelerates disk I/O response • from existing storageUses CPUs and memory from • general purpose servers as powerful, inexpensive cacheAnticipates next blocks to • be read & groups writes to avoid waiting on disks

10001011

11000

10111

PERFORMANCE

When computers write to a virtual disk, the information goes quickly into memory and later de-staged to disk, often grouped with other writes to minimize delays when storing the information to disk.The simplest way to look at caching on a DataCore node is to view it as a level 1 cache that can respond in less than 20 microseconds, whereas the caches on the disk array would be slower and pricier, taking somewhere in the hundreds of microseconds. Both of these caches aim to hide the much longer delay of the physical disk I/O which is in the order of 4000 to 6000 microseconds (or 4 to 6 milliseconds). In the diagram you see how the software uses the CPUs on the DataCore nodes to rapidly poll for inputs and immediately service input or output requests out of SAN-wide caches. Polling replaces slower (higher latency) interrupt servicing techniques that take much longer to recognize I/O events. The quicker the CPU, the faster we can turn around an I/O. The same polling method is used whether fielding requests from the SAN clients or responding to the back-end disks. Write coalescing reduces the delay in writing to disk by grouping inputs, whereas pre-fetching into cache anticipates blocks to be read given earlier reads from that section of the disk.

Turbo-charged Virtual Disk I/O

Average Response (microseconds)

DataCore L1 Cache <20Array L2 Cache 250-300Disk Drive 4000 - 6000

High-speedLevel 1 Caching

Poll for Inputs

Pre-fetch from DisksCoalesce

Writes

Output from Cache

CPUs

CPUs CPUs

CPUs

Un-cached Storage

Cached Array

Cached Array

Disk Subsystems

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Load balancing across the back-end channels into the physical storage pool complements

caching to improve response and throughput. The storage consumers on the SAN may also be doing host-based load balancing across their ports.Load balancing helps to overcome short-term bottlenecks that may develop when the queue to a given disk channel is overly taxed, or when one channel fails or is taken offline.

Load BalancingImprove response and throughput

Overcome typical storage-• related bottlenecksSpread load on physical • devices using different channels for different virtual disksAutomatically bypasses • failed or offline channels

PERFORMANCE

RAID (or Redundant Arrays of Inexpensive Disks) is a common way to gain better

performance and protection by spreading I/O’s across multiple disk spindles. Virtual disks may be intentionally striped across several physical drives or simply mapped to a logical RAID drive supplied by the underlying disk subsystems. Thin provisioning takes advantage of RAID striping to dynamically allocate more disk space when the initial set of drives runs out of room.

RAID StripingBetter protection and performance

Circumvents drive failures• Spreads I/O across • multiple spindlesOff loads RAID 0 & 1• Supports popular RAID • devices in pool

The built-in administrative interface in both SANmelody and SANsymphony provides real-time

status on the virtual storage pool. DataCore also offers optional analysis and reporting tools (SANmaestroTM) to track and chart historical behavior over extended periods. Such charts reveal trends in resource consumption and performance that can be used for tuning, troubleshooting and capacity planning. The information may be synthesized and exported to 3rd party packages for further analysis and billing.

Reveals SAN resource • consumption & performance trendsAssists with capacity • planning, utilization & quality of service decisions Export results to 3rd party • tools for further analysis, charge-back & billing

Analysis and ReportingTracks and charts long-term SAN behavior

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When it comes to non-stop access, synchronous mirroring deserves most of the credit. It

handles the real-time replication of I/Os for the ultimate in high-availability SANs. Having two or more nodes storing the data simultaneously in conjunction with multipath I/O drivers on the client computers eliminates the DataCore storage pool as a single point of failure. SANmelody allows you to configure redundant storage pools by synchronously mirroring between two DataCore nodes. SANsymphony scales to accommodate N+1 redundant nodes. Meaning that if you need 4 nodes to handle the I/O workload, you add a fifth node to absorb the added load when any one of them is taken out of service. During normal operations all five nodes would be fulfilling part of the work but each would have enough headroom to cover a portion of a nodal outage. For any mirrored virtual disk, one DataCore node owns the primary copy and another holds the secondary copy. They maintain these copies in lock step by synchronously mirroring updates in real-time from the primary to the secondary.

Synchronous MirroringReal-time I/O replication for High-Availability

Eliminates SAN or storage • as a single point of failure when combined with multipath I/O driversEnhances survivability using • physically separate nodesUpdates two distributed • copies simultaneously

Note: DataCore nodes do not share state to maintain the mirrored copies synchronized as one might in a clustered design. Our prior experiences with very high end cluster development has taught us that attempting to coordinated nodal state significantly increases complexity and negatively impacts scalability, so we intentionally shy away from it.

HIGH-AVAILABILITY

In the diagram below, Node A owns the primary mirror labeled “P” and Node “B” holds the secondary copy labeled “S” for a given virtual disk. The preferred path from the client computer to the virtual disk is assigned to the node that holds the primary copy of the mirrored set. Under normal operation, all read and write requests issued to that virtual disk will be serviced by the primary copy. The secondary copy need only keep up with new updates arriving from the mirroring function. Generally, nodes are configured to control primary copies for some virtual disks and secondary for others, thereby evenly balancing their read workloads. Should any errors be encountered on the preferred path, the client’s multipath I/O drivers automatically fail over to the alternate path without disrupting applications. The same is true if a node needs to be taken out-of-service for maintenance or upgrades.From a physical standpoint, best practices call for the DataCore nodes be maintained in separate chassis at different locations with their respective portion of the disk pool so that each can benefit from separate power, cooling and uninterruptible power supplies (UPS). The physical separation reduces the possibility that a single mishap will affect both members of the mirrored set. Round-trip network latencies govern the maximum distance between mirrored nodes. Current technologies support inter-node distances up to 35 kilometers using Fibre Channel.

Eliminate Single Points of Failure

“Virtual Disk”

SynchronousMirroring

Cache

Node A

ActiveActive

1

Cache

Node B

Separate Chassis• Different Location• Independent Cooling• Independent Power• Separate UPS•

Mirror (P)

Mirror (S)

Client

35 6

4

2

Fail-over

PreferredM P I O

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Another by-product of making storage interchangeable using DataCore’s storage

virtualization software is the ease with which you can relocate data from one physical disk to another, non-disruptively. We refer to it as virtual disk migration or volume replacement. It comes in handy during hardware upgrades as you seamlessly roll in new equipment in place of older hardware. Having copied the contents to the new drives in the background, the software will zero out the original disk and reclaim its space into the free pool.

Virtual Disk MigrationTransparently move contents from one disk to another

Allows non-disruptive • hardware disk upgrades for mirrored volumesClears & reclaims space • occupied on the original drive

MIGRATIONS & UPGRADES

The more visual example below shows how easily you can replace storage devices in the background while applications continue to run uninterrupted. Sometimes the older equipment can be put to good use as a lower tier device for less demanding requirements, or it can be decommissioned altogether. The choice is yours. DataCore also excels at migrating operating system images and data between physical and virtual machines (P-V) and between unlike virtual machines (V-V). The “Transporter option” rapidly imports and converts physical and virtual machine disk images encoded with a different format. It significantly shortens and simplifies transitions between dissimilar platforms. The migration is quick and verifiable at the outset while the bulk disk-to-disk copy occurs in the background. We never modify the original disk images on the source machine during the conversion to avoid irreversible migrations.

Non-disruptive Disk Upgrades and P-V-V Migrations

Old

Virtual disks remain active while contents are migrated to

a different device

New New

Retain or discard older device

Tier 1

Physical Storage

PoolTier 3

Tier 2

HA

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Once you’ve tried online snapshots, you can’t live without them. Snapshots capture a known good

point-in-time that may be used for several purposes without scheduling lengthy back-up windows. It may give you a recovery point to undo a patch or file deletion. Or it may be used to feed business intelligence analysis. They are also commonly used to verify new software enhancements in test and development before being put into production. Snapshots are invaluable in cloning working system images to provision identical new servers. Although snapshots utilities are commonplace in operating systems, hypervisors, backup software, and disk arrays, capturing them at the SAN level affords some major advantages. For one, there is no dependency on host software. Nor does it consume host resources. And you don’t need mutually compatible disk arrays. You can snap the contents of disks on a tier one array and place it on a tier 2 or tier 3 device, rather than tie up expensive space on the top-of-the-line equipment. In fact, DataCore snapshots reduce capacity consumption in two ways: 1) they can be set to capture only changes from the original source and 2) they may reside on thinly- provisioned volumes. DataCore snapshots may be triggered from Windows Virtual Shadow Copy (VSS-compliant) applications that temporarily quiesce the application and flush O.S. caches to ensure a consistent recovery image.

Online SnapshotsCapture point-in-time images quickly

Recover quickly at disk • speeds to known good stateEliminate back-up window• Provide “live” • environment for analysis, development & testingKeep snapshots in lower tier, • thin-provisioned storage

There’s some impressive magic that goes into making DataCore snapshots fast and lean. Part of it comes from the realization that generally, only a few blocks on most devices really experience much change. With that in mind, the snapshot can reference the original unchanged blocks most of the time without taking up any extra room. We need only keep a separate, unmodified copy of those blocks that get updated. And that copy is taken on the first change to that block, effectively giving us the frozen point-in-time. Think of the software as a traffic cop. If the block is unchanged, read from the source. If the block has been changed, read from the copy of the original contents kept in a separate bucket.DataCore gives you several snapshot variations. We just described the “Snapshot Image”. You can also ask it to completely clone the source disk in the background. We refer to it as a “Complete Image Copy.” You may refresh the snapshot to a later point-in-time using the “Image Update” command, or you can completely replace the source with an earlier snapshot using the “Source Update” command. That one is reserved for those cases when you have to undo changes.

BACKUP & RESTORE

Low-impact Backups

Original blocks saved here on

1st update

If unchanged, read from Source

Only changed blocks take up space

Back-up• Testing• Analysis• Recovery•

Source

Current Image

Source disk blocks

Earlier point-

in-time

Live updates

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BACKUP & RESTORE

some organizations must restore their environments to specific points-in-time that

may not coincide with the scheduling of their regular snapshots or backups. Nor can they afford to interrupt or quiesce applications so frequently. Continuous Data Protection (or CDP) is for them.

Continuous Data Protection & RecoveryReturn to any point-in-time without taking explicit backups

Dial back to restore an • arbitrary point-in-timeLogs and timestamps • wall I/Os No need to quiesce or • interrupt applications

This is a separately-priced SANsymphony option performed on a separate DataCore node. As the name implies, it continuously logs and timestamps I/Os written to designated virtual disks allowing you to restore the environment to any arbitrary point-in-time within that log. We call this feature “TravellerTM” as in time traveler. CDP automatically combines periodic snapshots with a log of time-stamped updates to roll back the image to an earlier point. The administrator can dial back to this prior state via an intuitive user interface. In this example, we have a rolling log covering the last 5 days of updates from which to fall back to.

Roll Back to Desired Point in Time

Hours• Days• Weeks•

Time-stamped Updates

CDP

Active

Cache

Synchronous Mirror

... days1June 30

@ 12 am

July 7 July 3 6:31pm

2 543

Snapshot

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Earlier, we discussed how synchronous mirroring fits into our solution for high-availability. We

spoke of an upper limit near 35 kilometers between mirrored nodes before round-trip latencies make lockstep replication impractical today. In other words, if you tried to synchronously mirror at longer distances, applications might time out waiting for the acknowledgement to come back from the remote end.

Remote ReplicationMaintain distant copies up-to-date without impacting local performance

Perfect for disaster recovery • or business continuityOnly needs a basic IP • connection to secondary siteBidirectional• Asynchronous•

OFFSITE DISASTER RECOVERY

DataCore’s remote replication function, internally called “Asynchronous IP Mirroring” or AIM, addresses requirements for secondary copies to be housed beyond the reach of synchronous mirroring, as in distant disaster recovery sites. It relies on a basic IP connection between locations and work in both directions. That is, each site can act as the disaster recovery facility for the other. The software operates asynchronously, meaning that it does not hold up the application waiting on confirmation from the remote end that the update has been stored in both places. Instead, it offers to do its best to keep up to date with changes at the local site, but makes no guarantees. It’s far better than trying to constantly make backup tapes and ship them to a safe house or paying extra for point-products to handle only this task.

Offsite Disaster Recovery Copies

Destination

SourceReplicated

Updates

Queued Updates

Cache

Active

Recovery Image

IP WAN Asynchronous

copy

Cache

Snapshot

Central Site

Disaster Recovery

Site

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ASR is a key component of DataCore’s comprehensive business continuity portfolio. It automates and

radically simplifies how one or more, smaller, remote IT facilities take over workloads from a central site in the event of a disaster or scheduled outage. Rather than attempt to fully recreate the central datacenter at another major site, ASR can distribute responsibilities for keeping the business going among a few remote offices and branch offices (ROBO) based on their computational, networking and storage capacities.

Advanced Site Recovery (ASR)Spread DR responsibility across multiple smaller sites

Effectively distributes • DR to remote offices/ branch offices (ROBO)Central site restoration is • built into the processUniversal coverage for • heterogeneous scenariosSame automated process for • virtual & physical systems

OFFSITE DISASTER RECOVERY

ASR also takes care of returning control of the workloads to the central IT site when the main IT center is deemed capable of accepting them. Unlike other approaches that can only address a subset of the IT environment, DataCore covers both virtual and physical servers without taxing applications, hosts, or hypervisors. Nor does ASR depend on duplicating expensive equipment offsite, such as top-of-the-line disk arrays and specialized networking gear. Only DataCore allows organizations to leverage readily available IT assets, often differing between sites, to minimize or eliminate the disruption and data loss attributed to planned and unforeseen site outages. In view of the fragmented and complicated alternatives, DataCore offers a refreshingly rational and cost-effective solution. ASR builds on the virtual disk provisioning, asynchronous remote replication and online snapshot features to constantly update remote sites with changes occurring at the central datacenter.

Automated, Distributed Disaster Recovery (DR)

Central Site

Branch A

Branch B

Branch CRemote Replication

HA

0709©2009 DataCore Software Corporation All rights reserved. DataCore, the DataCore logo, SANsymphony, SANmelody, Traveller, and SANmaestro are trademarks or registered trademarks of DataCore Software Corporation. All other products, services and company names mentioned herein may be trademarks of their respective owners.

For additional information, please visit: www.datacore.com or e-mail: info@datacore.com

System administrators control and monitor DataCore functions from one central console via an intuitive

user interface. The same tools are used across like or unlike devices. SANsymphony offers a richer, more comprehensive administrative experience that spans the entire SAN. It also automates certain tasks that would require manual intervention in other products.Special plug-ins are also available for integration into server virtualization consoles.

SAN-wide Centralized ManagementControl and monitor all SAN resources from one console

Automates laborious, • repetitive tasksIntuitive to operate• Universal tools work across • like or unlike devicesPlug-ins for integration • into Hypervisor consoles

MANAGEMENT

Intuitive Graphical Views

As you can see, DataCore offers a comprehensive set of storage virtualization and centralized storage management features that turn ordinary disk space into non-

stop, lightning-fast and waste-free storage pools. These integrated software capabilities reconcile disparities between different models of hardware devices from the same or different manufacturers, making them largely interchangeable. They yield unheard of flexibility and cost reductions in operations, procurement and system design.

Summary