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microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

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A CW buyer’s guide to VM backup & disaster recoveryOne benefit of the age of virtualisation is the substantial improvement virtual machines (VMs) have brought to live migration, server backup and disaster recovery. In this 10-page buyer’s guide, Computer Weekly looks at the products traditional and new suppliers have brought to market; the competition for the market playing out between Microsoft and VMware; how to mitigate some of the problems of virtual server backup to ensure seamless data protection; and asks, if cloud is good enough as a secondary backup for our critical applications now, why should it not become the standard primary platform of the future?

These articles were originally published

in the computer Weekly ezine

computerweekly.com buyer’s guide 2

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

Live migration entails moving active virtual machines (VMs) between physical hosts with no service interruption or downtime. it launched 11 years ago as a landmark development in datacentre infrastructure and is now a crucial part of virtualisation infrastructure software and deployment. A VM live migration allows administrators to

perform maintenance and resolve a problem on a host without affecting users.Moving active VMs from one hypervisor to another means you can balance the

performance and load of hypervisors or, in the case of hardware maintenance, evacuate hypervisors from active VMs. it enables users to conserve resources during non-peak hours by moving VMs to fewer servers. You can also optimise network throughput by running VMs on the same hypervisor. When live migration of VMs appeared in 2003, with VMware’s EsX 2.0, it became popular in the iT community.

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Key resources to prevent VM

live migration failures

Explore Microsoft

Hyper-V Live Migration

under the hood

Microsoft vies with VMware in the virtual machine marketVMware launched live migration in 2003. Since then, its capabilities have seen many enhancements, but Microsoft is starting to catch up, reports Jens Soeldner

Buyer’s guidevm backup & recovery

computerweekly.com buyer’s guide 3

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

six years after VMware pioneered VM live migration in 2003, Microsoft introduced a similar feature in hyper-V that was shipped with Windows server 2008 R2 – the previous version, Quick Migration, in Windows server 2008 required a short service interruption during migration.

Getting to grips with live migrationTo understand how live migration works, it is important to be aware of the VM’s basic components: storage (the virtual hard disk) and the configuration or state. storage is often located on a storage area network (sAn) and its configuration runs in a host server’s processor and memory. With the traditional process of a live migration, the VM’s state and configuration is copied from one physical host to another, but the VM’s storage does not move.

storage live migration – moving the disks of a VM from one location to another while the VM continues to run on the same physical host – became available in 2006/2007 with EsX 3.0/3.5. VMware’s current offering, vsphere 5.5, vMotion (live migration of VMs) and storage vMotion (live migration of the virtual disks) are part of the vsphere standard edition. Automatic load-balancing of VMs (distributed resource scheduling, or DRs) is available with vsphere Enterprise, automatic load balancing of disks (storage DRs) and vsphere Enterprise Plus. Leveraging vMotion requires that EsXi servers are being managed by Virtual center and that they are compatible (boiling down to compatible cPUs and a couple of minor requirements) with the same physical subnet.

Moving VMs between hypervisors that are not on the same physical network segment is not supported. Administrators need to tag an existing port or create a new VMkernel port for vMotion usage and live migration to be used by with one click in the vsphere client (either the traditional client or the web client). Using the web client, even live migration of VMs without shared storage is possible (shared-nothing live migration, introduced with vsphere 5.1).

shared-nothing live migration is a combination of traditional VM live migration and storage migration. The VM’s state and configuration is copied to a destination host and the file system is moved to the destination storage device. To prevent downtime, the VM’s state and storage remain running on the original host and storage location until the copying process is completed.

Evolution of VMware’s live migrationVMware has improved its live migration capabilities over the years and the application can now leverage multiple network interfaces to speed up live migration. in VMware’s upcoming vsphere 6, rumoured to be launching in March 2015, live migration over longer distances – with higher latencies and between virtual centre instances – is expected to be available.

DRs, which leverages vMotion to balance VM workload between physical hosts, has also been improved in recent product versions. it now boasts rules that take preferences into account and can evacuate hypervisors during non-peak hours to conserve resources using distributed power management (DPM), available with DRs as part of vsphere Enterprise Edition. VMware also updated storage vMotion in vsphere version 5.0 by moving from a dirty block tracking algorithm to i/o mirroring, improving the performance and reliability of its storage live migration capabilities.

Shared-nothing live migration iS a combination of traditional vm live migration and Storage migration

computerweekly.com buyer’s guide 4

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

Microsoft stealing VMware’s thunderMicrosoft introduced the ability to move VMs across hyper-V hosts with Windows server 2008 R2. This required VMs to reside on shared storage as part of a cluster. Even then, hyper-V wasn’t able to move multiple machines simultaneously. however, with Windows server 2012 and server 2012 R2, Microsoft continued to gain ground on VMware, introducing additional migration capabilities that put Microsoft more or less on par with VMware when looking at this specific feature.

since Windows server 2012 R2 hyper-V can store VMs on server message block (sMB) file shares, performing live migration on running VMs stored on a central sMB share is now possible between non-clustered and clustered servers, so users can benefit from live migration capabilities without investing in clustering infrastructure. Windows server 2012 R2’s live migration can also leverage compression, reducing the time needed to perform live migration by 50%, according to Microsoft.

Live migration in Windows server 2012 R2 can use improvements in the sMB 3.0 protocol too, which accelerate live migration without the VM having to be stored on a sMB 3.0 share. if the customer is using network interfaces that support remote direct memory access (RDMA), the flow of live migration traffic is faster and has less impact on the cPUs of the hosts involved.

storage live migration was introduced to the hyper-V feature set with Windows server 2012. Windows server 2008 R2 allowed users to move a running VM using traditional live migration, but you had to shut down a VM to move its storage in Windows server 2008 R2. With the current version of hyper-V, you can transfer a VM’s backing storage files to a new location with no downtime, a feature that is critical for migrating or updating storage, or when a load redistribution on the storage side is needed.

VMware vSphere 5.5 versus Microsoft Windows Server 2012 R2 Hyper-V in their current versions, VMware’s vsphere 5.5 and Microsoft Windows server 2012 R2 hyper-V support shared-nothing live migration, which makes it possible to simultaneously change the location where the VM is being run as well as the backing storage location for the running VM – a feature that provides additional flexibility, especially in small business environments where centralised storage is not always present.

Microsoft has gained substantial ground in many areas, but experts agree there is still a gap between hyper-V and VMware vsphere when looking at enterprise-level features. hyper-V lacks features, such as vsphere storage DRs, though other features, such as storage spaces, offer similar functionalities. But hyper-V comes in a powerful free version,

“hyper-V server 2012”, which includes native support for Live Migration of VMs across clustered and non-clustered hosts at no extra cost, while VMware’s free hypervisor has limited functionality.

Going beyond live migration, both suppliers support replication capabilities, which is easy to set up with

VMware vsphere and Microsoft’s hyper-V. combined with the cloud offerings of the suppliers, VMware vcloud Air Disaster Recovery and Microsoft Azure site Recovery, users can replicate and failover VMs to their suppliers’ cloud offerings, giving extra options for self-service disaster recovery protection and business continuity. n

› Let’s get this straight: VM live migration› Keys to a painless data migration process

› Key choices in virtual machine backup

With the current version of Hyper-V, you can transfer a

virtual machine’s backing storage files to a new location with no downtime

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Jens Soeldner is a cloud infrastructure and virtualisation specialist working at German consultancy Soeldner Consult.

computerweekly.com buyer’s guide 5

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

Data protection is an essential part of all iT operations and has, until recently, been achieved by directly backing up physical servers over the network. But the move to virtual server environments has changed forever the landscape for successful backup of applications data, presenting a number of challenges.

Virtual server backup: The performance problemThe move from physical to virtual servers provided many iT organisations with the oppor-tunity to consolidate and reduce the amount of hardware resources needed. This was one of the main selling points of the first wave of virtualisation – consolidation to fewer servers because most of them weren’t fully utilised.

But the backup infrastructure is an area that has always struggled with performance issues, even when there is a dedicated backup network. Therefore, backing up virtual servers using physical server infrastructure and methods has often resulted in big problems.

Where once one app on one server was backed up, now multiple virtual servers in a single box require protection. For that reason, virtual server backups can experience severe bot-tlenecks when using traditional backup methods that copy data from each virtual machine (VM) as if it were a physical server.

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Virtual server backup

products surveyed

Backup versus

replication, snapshots, CDP

in data protection

strategy

Challenges in virtual server backup and how to tackle themChris Evans discusses some of the problems associated with virtual server backup and how they can be mitigated to ensure smooth and efficient data protection

Buyer’s guidevm backup & recovery

computerweekly.com buyer’s guide 6

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

The answer here is to avoid backing up data from the guest VM and instead to deploy backup applications that can copy directly from the host using backup-specific application programming interfaces (APis) such as VMware’s vstorage APis for Data Protection (VADP). All VM-aware backup products are capable of using these APis to back up data without hav-ing to access each guest.

one benefit of running host-based backups is that traditional backup agents can be elimi-nated, removing a whole set of maintenance and management tasks needed to keep the agents up to date.

Virtual server backup: The tracking problemin the physical server world, the server is clearly identifiable and tracked through an iP address and/or Dns name. servers rarely move or change iP address, so a backup that fails due to an inability to contact the server can be easily resolved.

in the virtual world, things aren’t as simple. While it is true to say most virtual servers don’t change their iP address, most also aren’t backed up directly, but backed up through the host hypervisor.

Virtual machines can easily be migrated between physical servers and storage, so keeping track of each VM in the backup infrastructure becomes more com-plex. The result is that a VM migration may well cause the next backup to fail.

The answer is to reference a virtual machine, not through the physical host on which it resides, but via a more abstract reference to the group of physical serv-ers that support the VM, such as the cluster name or, in the case of VMware vsphere, the datacentre object. By abstracting the reference to the VM, both backup and restore processes are no longer dependent on the physi-cal host hardware, which provides operational benefits by reducing the work involved in restores for clusters that have been physically or logically reconfigured.

Virtual server backup: The granularity problemDuring data recovery, most restore requests are for individual files, a directory, or for data within an application such as an email attachment. it is rare that an entire server needs to be recovered. Most restores are therefore very granular in nature, and require the recovery of a small piece of the data that constitutes a server or application.

Virtual server backups that simply back up the files that comprise the VM may have prob-lems restoring individual pieces of data unless the software is aware of the contents of the backup and is able to understand virtual machine disk formats. Worse still, if the backup software cannot decode the contents of the backup, it may be necessary to restore the entire

VM, albeit to a temporary location, to recover a single file, resulting in restore delays and unnecessary network traffic.

Backup software needs to be able to understand the content of the backup and restore objects from within backup files directly, without having to restore more backup data than

necessary. Today’s more advanced products are able to understand the format of application data – email systems and databases, for example – and offer restores of individual application objects. obviously, these technologies need to be used with care, as restoring parts of data into an application could lead to logical corruption.

virtual machineS can eaSily be migrated between phySical ServerS and Storage, So keeping track of each vm in the backup infraStructure becomeS more complex

› Backup challenges: Backing up virtual servers› Key choices in virtual machine backup

› Podcast: Virtual server backup fundamentals

computerweekly.com buyer’s guide 7

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

Virtual server backup: The media problemcontemporary backup technology uses techniques such as changed block tracking to back up virtual machines. These systems are well-suited to storing backup data on disk, as they require access to the initial backup plus all data changes to perform restores.

But backup subsystems that rely solely on disk come with some caveats. Disk-based backup targets aren’t necessarily scalable – at least not in a way that is eco-nomically desirable – and don’t offer easy portability to take data off site for full disaster recovery, for example.

The solution is to look at backup systems that are capable of supporting multiple media types, including tape, and those that offer the ability to create syn-thetic backups, such as a full system backup based on the original backup plus all subsequent incremental block changes.

Virtual server backup: The process problemVirtual server backup and data protection can be achieved through various methods and technologies. As well as backup software, there are other ways to secure virtual machines that rely on the fact that VMs are stored as files on disk. This means backups can be made via snapshots or replication on shared storage.

Although array-based replication and snapshot func-tionality can work well, care has to be taken to ensure that using these methods will result in a consistent and comprehensive backup policy.

For example, snapshots don’t cover the scenario of total array failure, such as could be experienced through fire or flood, and replication may not provide the right level of granular-ity for recovery when the minimum recovery point is a logical unit number (LUn).

That leads to the conclusion that virtual server data protection is best implemented using a variety of techniques. n

diSk-baSed backup targetS aren’t neceSSarily Scalable and don’t offer eaSy portability to take data off Site for full diSaSter recovery

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computerweekly.com buyer’s guide 8

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

We do backups because we know we have to – in case we lose the primary versions of data and/or the systems that create and manage that data. it could just be that the original gets accidentally deleted or changed; however, the possibility of system failure will be a top priority for many. That could be

anything from a disk crash on a user’s device to a datacentre crushed by a meteorite. When such a failure happens, it is not just data that needs restoring, but the full working environ-ment; in other words, disaster recovery.

Backup and disaster recovery are not directly interchangeable terms; but disaster recovery is not possible without backup in the first place. Disaster recovery is having the tested where-withal to get systems restored and running as quickly as possible, including the associated data. The increasing use of virtualisation has changed the way disaster recovery is carried out because, in a virtual world, a system can be recovered by duplicating images of virtual machines (VM) and recreating them elsewhere. VM replication, disaster recovery and the way the market has adapted to virtualisation are critical topics to consider.

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VM backup methods for

quick VM recovery

How do VM backup tools fit in a cloud

backup and disaster

recovery environment?

Backup and disaster recovery in the age of virtualisation

One of the benefits of using virtual machines is the scope for improved backup. Bob Tarzey looks at the product offerings from traditional and new suppliers

Buyer’s guidevm backup & recovery

computerweekly.com buyer’s guide 9

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

in the old days, if a server crashed then you would probably go through the following steps:n Get a new server. hopefully you would have a spare to hand – probably an out-of-date

model, if it had not been needed for some time;n Then, either: install all the systems and applications software, attempting to get all the

settings as they were before, unless of course you had done that in advance – which would not have been possible if you had only invested in one or two redundant servers on standby for many more live ones, not knowing which would fail;

n or, for a really critical application, you may have had a “hot” standby, all fired-up and ready to go. however, that would have doubled the costs of application ownership, with all the hardware and software costs paid twice;

n Restore the most recent data backup, for a database that might be almost up to date, but for a file server, an overnight backup may be all that is available, so only as far back as the end of the last working day. Anything that was in memory at the time of the failure is likely to have been lost. how far back you aim to go is defined in a backup plan as the recovery point objective (RPo).

Backup in the age of virtualisationVirtualisation changes everything and increases the number of options. First, data can be easily backed-up as part of an image of a given virtual machine (VM), including application software, local data, settings and memory. second, there is no need for a physical server rebuild; the VM can be recreated in any other compatible virtual environment. This may be spare in-house capacity or acquired from a third-party cloud service provider. This means most of the costs of redundant systems disappear.

Disaster recovery is cheaper, quicker, easier and more complete in a virtual world. in the idiom of backup, faster recovery time objectives (RTos) are easier to achieve. At least, that is the theory, but it can get more complicated with the need to co-ordinate different VMs that rely on each other – for example an application VM and a database VM – so testing recovery is still paramount and can forestall problems in live systems.

There are a number of different approaches, from tightly integrated hypervisor-level VM replication through to disaster recovery as a service (DRaas).

Integrated hypervisor replicationThe leading virtualisation platform suppliers – including VMware, Microsoft hyper-V and citrix Xen – offer varying levels of VM replication services embedded in their products. They are tightly integrated into the hypervisor itself and so limited to a given virtual envi-ronment. however, this does give them the potential to achieve the performance needed for continuous data protection (cDP) using shadow VMs as virtual hot standbys, minimis-ing both RPos and RTos.

There are other products that tightly integrate VM replication at the hypervisor level, for example EMc’s RecoverPoint, which supports the co-ordinated replication and recovery of multiple VMs, so it can ensure a VM running an application is consistent with an associated database VM. currently this is only for VMware but hyper-V and cloud management stacks such as openstack are on the horizon.

Another is Zerto, which says it has built in better automation and orchestration than the virtualisation platform suppliers, further minimising the impact on the run-time environment. Zerto currently supports just VMware but has plans to extend support for hyper-V and Amazon Web services (AWs) which means, in the future, it will support failover from an in-house VMware system to, say, AWs or another non-VMware-based system. its product could also be used for pre-planned migration of workloads.

VM snapshottingMany other virtual-aware tools work by taking snapshots of VMs at given intervals. This involves pausing the VM for long enough to copy its data, settings and memory before

computerweekly.com buyer’s guide 10

Home

microsoft vies witH vmware in tHe virtual

macHine market

vmware launcHed live

migration in 2003. since tHen,

its capabilities Have seen many enHancements,

but microsoft is starting to

catcH up

cHallenges in virtual server

backup and How to tackle

tHemHow to

mitigate problems

associated witH virtual

server backup to ensure

smootH and efficient data

protection

backup and disaster

recovery in tHe age of

virtualisationtake a look at

tHe virtual macHine

products from traditional

and new suppliers to

realise tHe benefits of

improved backup

Computer Weekly buyer’s Guide

returning it to its previous state. The snapshot can be used to recreate the VM over and again. The RPo depends on how often snapshots are taken (which could be often enough to be close to cDP, but that would affect overall performance). The RTo depends on little more than how quickly access can be gained to an alternative virtual resource which, with the right preparation, should be almost immediately.

A number of new suppliers specialise in virtual environment backup. swiss-based Veeam launched its product in 2008 and supports VMware and Microsoft hyper-V. nakivo (founded 2012) only supports VMware. As these products have been built for a virtual world, they have many of the required adaptations built-in from the start, for example creating VM snapshotting and network acceleration to make off-site replication more efficient.

The traditional backup suppliers have adapted their products. For example, symantec has just released Backup Exec 2014, which it believes matches the capability and performance of the new arrivals. Dell claims that its AppAssure mimics cDP by using a “smart agent” that avoids freezing the VM and takes a snapshot at least once every five minutes. commVault’s simplana and Arcserve have also had the challenge of catching up.

one difference with many of the traditional suppliers is their capability to support both older physical environments alongside virtual ones, which remains the situation in many organisations. it also means their products are often used for migration, that is, for backing up a physical server and restoring it as a VM.

Many cloud infrastructure service providers, for example Rackspace and Amazon provide VM replication, enabling customers to put their own failover in place, but generally this is limited to their own platforms.

Disaster recovery as a service (DRaaS) providersThe widespread use of virtualisation and availability of cloud platforms for recovering workloads has led to a proliferation of DRaas offerings. here the replication of VMs is embedded in the service, so the customer has little to do other than due diligence and to sign on the dotted line.

some are offered by cloud/hosting service providers; for example nTT communications has a European offering in partnership with Us-based DRaas provider Geminare. Broader disaster recovery specialists such as sunGard and iBM include DRaas in their portfolios.

DRaas providers provide unique value to make it worth their customers’ while. some take this to a new level, for example Uk-based Plan B Disaster Recovery says its Microsoft Windows server DRaas offering can guarantee recovery, because it includes nightly testing of the recoverability of the images it takes of its customers’ server environments. This not only ensures recoverability but often pre-empts problems the customer has yet to notice. Plan B operates at the application level so is hypervisor-neutral, supporting VMware, hyper-V and Xen. Plan B’s service can image physical servers as well as virtual ones.

Quorum offers a service called onQ that was originally developed for the Us navy to enable the rapid movement of processing from one part of a ship to another in times of battle dam-age, so it is very fast and very resilient, supporting physical or virtual Linux and Windows servers. onQ is also hypervisor-agnostic. in the Uk it uses a local datacentre partner to

recover the customer server images as VMs, which it claims allows RTos as quick as a server reboot.

interestingly, Plan B says that, whenever its service has been invoked to recover a physical server in a virtual environment, the customer does not go back. in other words, disaster recov-ery services can be used to migrate to virtual environments,

but can also provide the motivation to do so in the first place. And that may have got you thinking – if cloud is good enough as a secondary backup for even our most critical applica-tions, could it not actually also become our primary platform in the longer term? n

Bob Tarzey is a director at IT analyst company Quocirca

› How virtualisation changed disaster recovery› Cloud, virtualisation and disaster recovery

› Best practice in backup and recovery