Lab Review: Disk imaging for physical and virtual machines

Paragon's Drive Backup 10 Server software leverages disk imaging tools to simplify storage management issues, from consolidation to disaster recovery protection, in both physical and virtual environments.

By Jack Fegreus, openBench Labs

-- Entrenched at the top of the list of storage challenges is data protection, which includes the perennial problem of data backup. IT groups at large enterprises continue to struggle with meeting Service Level Agreements (SLAs) that continue to tighten both the Recovery Point Objective (RPO)—the maximum amount of data measured in time prior to the disruption that could be lost in the recovery process—and the Recovery Time Objective (RTO)—the maximum period of time that it could take to recover. Meanwhile, IT administrators at SMBs, who often have less storage expertise and tighter budgets than their peers at larger enterprises, struggle with more prosaic issues, such as choosing technologies to simplify backup processing within shrinking backup windows.

To help IT deal with data protection issues at all types of sites, Paragon Software Group's Drive Backup 10 Server creates exact image copies of live disk drives on physical and virtual systems running a Windows-based OS. With a technology foundation featuring synthetic backups, along with full support for both VMware vSphere and Microsoft Hyper-V, Drive Backup 10 extends standard data protection constructs with wizards that employ the same menus for backup and system migration processes to support physical-to-virtual (P2V) consolidation.

What's more, IT can use the Paragon Script Language (PSL) to customize the synthetic and differential backup wizards in Drive Backup 10 Server. Using PSL, IT administrators can create scripts to automate end-to-end data protection processes, which can implement Paragon Hot Backup and Microsoft VSS snapshot technologies to maintain transactional integrity. In particular, the Paragon synthetic backup scheme by default supports differential backup, which on multiple VM backup jobs can reduce storage capacity requirements on the order of 30-to-1 without the extra processing incurred with inline data deduplication. As a result, administrators can leverage PSL to invoke fast differential backups to support near-CDP levels of replication for VMs, and then match that aggressive RPO with an equally aggressive RTO using synthetic backup images that can be restored in minutes.

Of particular importance for SMBs, Drive Backup 10 Server is easy to deploy and use. In addition, the optional Paragon Remote Management (PRM) application provides a single management point for launching and running scripts developed with Drive Backup on systems across a distributed enterprise. As a result, PRM is especially useful when running multiple VMs, as IT administrators can rapidly back up and restore systems in minutes to garner an immediate ROI.

In addition, IT does not have to purchase extra-cost options to leverage Drive Backup 10 Server in a virtual environment. The software provides dedicated image-level data protection for VMs running Windows on a VMware hypervisor without requiring integration with VMware Consolidated Backup (VCB). VCB assumes a shared-disk storage infrastructure via a Fibre Channel or iSCSI SAN. For SMB sites functioning well with direct-attached storage (DAS) and simple file sharing via NAS or FTP storage servers, the need to introduce a SAN in order to protect data presents a prodigious stumbling block.

On the other hand, SMBs can use Drive Backup 10 Server to provide VMs with full data protection without a major storage infrastructure change from DAS to SAN. Paragon also enhances the value of Drive Backup 10 and PRM for SMB sites with support for the ESXi hypervisor under the free public license. With more servers featuring ESXi firmware bundles, the ability to work with Windows-based VMs hosted on this hypervisor with the public license is particularly important at SMB sites.

VMs, virtual tapes, and synthetic backup

To assess the ability of Drive Backup10 to simplify backups and disaster recovery, openBench Labs set up a workstation and three servers to host a data protection scenario based on VMware vSphere 4. Two servers hosted the VMware virtual environment—one ran the ESX 4 hypervisor and the other ran ESXi 4. All hypervisor datastores were created on a Xiotech Emprise 5000 disk array, and each VMware host shared SAN access to every datastore.

We ran Windows Server 2003 on the other server and Windows 7 on the workstation. Both systems were made members of our Testlab domain. To configure and manage the VMware environment, we installed vCenter 4 on the Windows proxy server.

On each of our two VMware hosts, we configured VMs as application servers running 32-bit Windows Server 2003, SQL Server, and IIS. For our testing, we installed Drive Backup10 Server and Paragon Remote Management (PRM) v2.1 Client on each VM. More importantly, by running a 32-bit Windows OS on each VM, we were able to launch and execute scripts developed with Drive Backup 10 with just the PRM Client installed. To manage our PRM Clients, we installed PRM Console on our Dell workstation. We then set up a PRM storage volume on our physical server running Windows Server 2003.

openBench Labs also tested the ease with which we could consolidate our older Dell Dimension 4550 workstation, which was provisioned with a single Pentium 4 processor running Windows 7, to a VM with two Xeon CPUs. A frequently overlooked advantage of virtualization is the ability to upgrade VMs with additional resources on the fly.

With respect to the deployment of Windows server VMs, we paid particular attention to our host server running the ESXi hypervisor, which has a significant architectural difference from that of ESX. To keep the hypervisor compact, VMware does not implement a service console in ESXi. Without this mechanism for integration, a number of advanced functions, including vMotion, are not available with ESXi when using the free public license.

ESXi license limitations, however, do not affect Drive Backup 10 Server. Since the software runs within a VM to handle the logical data structure of the VM's disks, the application is insulated from the choice of a datastore to hold a virtual disk. As a result, SMB sites can provision one or more ESXi servers exclusively with DAS and still fully protect the VMware environment.

For uniformity across our tests, we stored all of the backup images on our Windows proxy server. In particular, we provisioned the server with three identical 500GB volumes from the Emprise 5000 array. In this way, each backup application had a dedicated central vault and each vault had identical I/O performance characteristics. For our tests, we used standard NAS connectivity; however, we could have equally utilized FTP connectivity for the Paragon data store.

On the system drives of each of our VMs, we employed thin provisioning, which was introduced with the ESX 4 and ESXi 4 hypervisors. Each of these volumes was virtualized as a vmdk file in a VMware datastore. Except for the VM used to test the feasibility of using DAS, we stored all user work files on Raw Device Mapping (RDM) disks.

An RDM volume is a logical disk volume that is formatted by the VM with a native OS file system. That makes an RDM volume directly accessible by other physical, as well as virtual, systems running the same OS. In addition, we configured all RDM volumes in virtual compatibility mode via the creation of an optional vmdk mapping file. In this way, a physical RDM volume remains manageable through VMFS.

Finally, as Drive Backup10 Server is a disk-to-disk (D2D) backup scheme, many sites will be concerned over the issue of disk storage utilization. Paragon resolves this issue with a synthetic backup scheme, based on changes in disk sectors. What's more, Backup 10 Server creates disk images based on the data and the logical file structure on the disk. As a result, the software handles free space—whether physical or virtual—in the same way. Essentially, this amounts to a backup image that is analogous to thin provisioning for every disk being backed up.

From physical migration to virtual consolidation

Drive Backup 10 presents administrators with an easy-to-use interface that is the same for physical and virtual machines. An administrator applies a collection of automated wizards to the system's drives, scheduled tasks, and backup archives. In the process, jobs can be saved as scripts that can be customized to the explicit needs of a site. Jobs can be launched in virtual mode to review the final process before physically committing the job.

To accelerate the ROI payback from a virtualization initiative, tools to simplify conversion of physical systems to virtual machines are essential. This is particularly important for any system running Windows, which is very sensitive to operating environment changes. While the ability to make an exact image copy of every disk drive is sufficient for an IT administrator to support a backup process, sufficiency wanes when a disk image must be moved from one PC to another.

With CPU processing power and disk bit density continuing to double every 18 months, Paragon developed a reputation in an important IT niche as a primary purveyor of tools to help migrate and copy Windows-based computer systems across evolving PC hardware platforms. To provide a unified solution for backup, disaster recovery, and server consolidation, Drive Backup 10 enables storage administrators to create exact duplicates of every live disk on a server or a workstation, including the system's operating system, all configuration files, programs, updates, and databases. More importantly, to meet the advanced needs of physical-to-physical (P2P) system migrations and disaster recovery operations, Drive Backup provides IT administrators with the capability to modify disk partitions and change device drivers in the system partition. What's more, the software extends these file manipulation techniques back into other functions: For example, an administrator can filter and exclude file types from sector-based image backup.

When upgrading a workstation running Windows Vista to Window 7, administrators have two options: Update the existing system or install a fresh copy of Windows 7 without any site modifications or software installed. Using Drive Backup 10, we were able to copy the running OS to another disk partition in a single operation, and we were able to adjust the physical characteristics of the new partition.

System consolidation and P2P migration invariably involve an upgrade in the technology of the underlying environment. In particular, an OS upgrade, whether for a server moving from Windows Server 2003 to Windows Server 2008 or a workstation moving from Windows XP to Windows 7, will likely require the need to increase the size of the system partition.

Driver file changes are just as important in a disaster recovery scenario as it is in a P2P migration. Few sites can afford to purchase new servers that with good fortune will never be used. It is often more cost effective to utilize an older existing server as a hot-backup system while the original server is repaired.

P2V fast track

Compared to the complexity of orchestrating a hardware change, migration to a well-defined VM is a relatively easier task. Reflecting that reality, the Drive Backup 10 GUI presents IT administrators with a single management point for backing up, restoring, and migrating data across both physical and virtual machines, including both VMware ESX and Microsoft Hyper-V servers. All of the numerous Paragon wizards consistently handle backup and restore tasks for both physical and virtual systems, and specialized one-button options are available to perform physical-to-virtual (P2V) consolidation tasks.

Assuming that there are no applications that rely on specialized hardware that must be directly attached to a computer, consolidating physical systems as virtual machines is frequently a straightforward process. In such a situation, sticking point issues are far more likely to be related to software licensing than technology.

To move our Windows 7 workstation environment to a VM, we needed to move two key storage volumes that were home to the OS and applications software to virtual volumes represented by vmdk files. The Drive Backup 10 P2V Copy wizard made quick work of this task. We were presented with a series of menus that identified the target environment—an ESX server—enabled changing the size of the virtual target volume, and set the location of drivers and utilities—the VMware Tools distribution—needed to adjust the OS to boot in the new virtual environment.

We tested the ability to consolidate a physical workstation running Windows 7 onto a VMware host. Using Paragon's Drive Backup 10, the entire process of creating two disk image copies ready for use on a host running ESX took about 30 minutes as we applied the P2V Copy wizard to the local disk volumes that were used to store the OS and software applications. On our physical system, those volumes were stored locally on a DAS RAID array. Work files were maintained on a SAN-based volume accessed via iSCSI.

In the P2V Copy wizard, we identified the storage volume to copy and the target hypervisor as an ESX server. For our OS system boot volume, we also pointed to the location of the VMtools ISO CD distribution, which Drive Backup 10 uses to adjust the OS—a process that is part of Paragon's Adaptive Restore technology—with the appropriate drives to boot in a VM. We then created the appropriate files in a directory on our Windows proxy server. For an ESX host server, the P2V Copy wizard creates two local vmdk files, one for the volume's boot block, which is consistent with the way that VMware vSphere vCenter imports and exports vmdk files.

Our next step was to create a directory in a datastore on the ESX host and import the vmdk files created by Drive Backup10. In that process, vCenter combined the boot block and volume into a vmdk file recognizable by the hypervisor. We then created a new VM and assigned the two vmdk files imported from our Windows server as two of its three drives. For the data volume, we simply redirected the SAN volume from the physical machine to the VM and imported it as an RDM disk in virtual compatibility mode. In about 30 minutes we were ready to boot our VM with upgraded memory and CPU resources. All of the software came up perfectly in the new environment; however, we needed to reregister about a third of our applications to continue running in their upgraded environment.

We were also able to repair vmdk-based drives for VMware virtual machines. For example, we were able to take a system drive created for use on a VM within the VMware Workstation, which by default uses IDE emulation. When used for a system drive on a VM hosted by ESX, this IDE drive blocked all access to the VM's virtual CD ROM drive. As a result, we could not load the VMware tool kit, which uses the CD ROM interface.

What's more, the settings file for any VM that imported our IDE drive would report that the IDE drive was provisioned for only 4GB. That provisioning error naturally generated error alerts. The only way to resolve the situation was to install Paragon Drive Backup 10 and run the P2V wizard on the IDE volume. Only after exporting and re-importing the adjusted system volume, could we mount the drive as a SCSI disk with the correct VM settings.

Synthetic backup for VMs

The advanced technologies of Drive Backup 10 are also reflected in the product's backup and restore functionality and performance. Using the archive view of the main interface, an IT administrator can easily launch and customize sophisticated backup processes for a VM just as easily as a physical system. There is no difference in terms of how the software is used between a virtual and physical system.

Using the wizards in the Drive Backup 10 GUI, we implemented a series of differential backups and were able to convert them into synthetic full backups that could be mounted as a virtual drive from which files could be retrieved in a simple drag-and-drop process.

From the Archive view of the Drive Backup GUI, an administrator easily manages and customizes data protection tasks. For all of our backup tests, each VMware VM was configured with a 25GB system disk using thin provisioning and virtualized as a vmdk file. In addition, each VM was provisioned with a 25GB RDM volume for working data.

Since Drive Backup 10 Server is able to analyze the logical disk structure of any volume, only drive sectors with real data were backed up. As a result, our space savings from data compression were not inflated with blank data. A typical full backup yielded a 3-to-1 compression ratio for the two drives using the default compression level. Increasing compression to Paragon's highest level yielded a 3.5-to-1 reduction in storage, but increased wall clock processing time about 50%.

More importantly, Drive Backup 10 Server provides for differential backups of drive images and the building of a synthetic full backup from any differential backup and the initial full backup that the differential backup referenced. In our tests, differential backups were typically only a few hundred MBs in size and took less than three minutes to process.

Using a synthetic backup scheme, a site only needs to run an initial full backup once. After that, a modern rotation scheme would run differential backups for a period of time determined by the rate of change in the site's data. As the site's data changes, the length of time required for a differential backup will increase. At a defined point based on the length of time needed for a differential backup, a new synthetic backup can be generated using an existing differential backup. That synthetic backup then becomes the new baseline for differential backups, which will again be fast and small in size. Alternatively, a full backup can be run to create a new baseline for differential backups.

Drive Backup 10 Server, however, goes far beyond the capability of recovering client files or complete drive images from a single backup process. At any time, an IT administrator can mount a full or synthetic backup of a disk volume. From the mounted volume, files can be copied at will without going through a restore process. More importantly, IT can use the ability to mount backup images to test and debug versions of software, before introducing them into a production environment.

Drive Backup's most powerful feature, however is the ability to generate an editable script from any backup operation. Starting with a basic script, an IT administrator can then customize a more complex site-specific backup policy. In particular, we customized a differential backup script to generate a unique time stamp for both the backup file and the directory holding the file. We then scheduled the script to run any time the system was idle for 5 minutes. Given that a differential backup took less than three minutes, this scheduling scheme provided our test environment with a near continuous data protection (CDP) process.

Control scripts

The script engine that is critical to customizing processes for Drive Backup Server 10 is also at the heart of Paragon Remote Management (PRM), which is part of the Paragon Infrastructure Package. As part of our testing, openBench Labs examined PRM 2.1, which provides IT administrators with a GUI-based console for  launching, managing, and reporting on data protection processes in a complex environment that can include multiple, non-collocated, physical and virtual systems.

From a software perspective, there are three components that need to be installed on various systems: the PRM Console application for launching and reporting on scripts that were developed using Drive Backup Server; PRM Storage, which is a shared directory for storing information on clients, the scripts that will be assigned to client tasks, task logs, and backup images; and the PRM Client, which includes a script engine for running assigned scripts on either physical or virtual machines.

Once we had installed PRM clients on multiple VMs running Windows Server 2003, we were able to group the systems and apply the standard PRM backup scripts to all of the members of a group simultaneously. We grouped VMs based on their host server and with one command applied a full backup script to all of the VMs running on our ESX host.

At the foundation of a PRM configuration are the console application and the shared storage directory. For our tests, we installed the PRM Console on our Windows 7 workstation and located shared PRM Storage on a fast, high-capacity, SAN-based volume attached to our Windows proxy server. Once the PRM Console and Storage are established, the edge of the data protection domain can be populated with PRM clients running on physical or virtual machines running Windows. In the case of a 32-bit OS, it is not necessary to install Drive Backup Server in order to run the scripts, as the PRM Client includes a Paragon Script Language (PSL) engine.

More importantly, the infrastructure and script-based execution model of PRM fits perfectly into any IT service management (ITSM) initiative. Understaffed IT departments have long sought to improve operations productivity via software tools designed to help resolve ad hoc resource problems. Better firefighting, however, cannot resolve the fact that changes to the computing environment introduced by IT cause 80% of all computing disruptions.

Given that statistic, ITSM initiatives have as their goal the automation of the standard tasks carried out by systems and storage administrators on a daily basis. The idea is to build classic quality control (QC) practices for process management into the routine tasks of IT administrators in order to eliminate the 80% of problem incidents that are attributable to IT.

In addition to the basic scripts included with PRM, we saved customized scripts from Drive Backup 10 to the script templates folder on the PRM Storage server. In this way, we were able to control the backup operation and direct the location of the backup image to the PRM Storage server.

That's why PRM, which provides IT with a platform that consolidates routine procedures and reporting of end-to-end data protection processes into a management framework automated by standardized scripts, can be a powerful QC tool. What's more, Drive Backup 10 can easily be pointed to the PRM Storage server archives to drill down on basic operations and gain a vital edge in complying with rigorous SLAs.

Jack Fegreus is the CTO of openBench Labs.


UNDER EXAMINATION: Disk image backup software

WHAT WE TESTED: Paragon's Drive Backup 10 Server, Paragon Remote Management 2.1


Dell Dimension 4550
-- Pentium 4 CPU
-- 2GB RAM
-- Windows Vista/ Windows 7
-- Drive Backup 10 Server
-- Paragon Remote Management 2.1 Client

Dell 1900 PowerEdge server
-- Quad-core Xeon CPU
-- 4GB RAM
-- Windows Server 2003
-- Drive Backup 10 Server
-- Paragon Remote Management 2.1 Console

Dell 1900 PowerEdge server
-- (2) Quad-core Xeon CPUs
-- 8GB RAM
-- VMware ESX
-- (8) VM application servers
-- Windows Server 2003
-- Drive Backup 10 Server
-- Paragon Remote Management 2.1 Client
-- SQL Server
-- ISS
-- (1) dual-processor VM workstation
-- Windows 7
-- Drive Backup 10 Server
-- Paragon Remote Management 2.1 Client

Dell 1900 PowerEdge server
-- Quad-core Xeon CPU
-- 4GB RAM
-- VMware ESXi
-- (2) VM application servers
-- Windows Server 2003
-- Drive Backup 10 Server
-- Paragon Remote Management 2.1 Client
-- SQL Server
-- ISS

Xiotech Emprise 5000 disk array
-- (2) 4Gbps FC ports
-- (2) Managed Resource Controllers
-- MPIO support for Windows and VMware
-- (2) DataPacs


• Drive Backup 10 unifies data protection and system consolidation for IT with a synthetic backup process and consistent wizards.
• Drive Backup 10 does not use VCB when backing up or copying VM disk data, which allows SMB sites with or without shared storage to leverage ESXi or ESX.
• Via support for differential image backups, Drive Backup 10 can leverage the synthetic backup to support very narrow backup windows for near CDP.
• Drive Backup 10 provides proprietary hot-backup technology to ensure VM transaction consistency and supports VSS-aware Windows applications such as Active Directory, SQL Server, and Exchange.
• Software compression reduces backup data traffic and storage requirements.
• A single backup can be restored as VMware container files, logical files for the guest VM, or can be mounted as a logical disk volume by the VM
• Paragon Remote Management (PRM) provides a centralized management and reporting application that creates a central repository for logs, backup images, and scripts that automate processing and reduce operator errors.

This article was originally published on February 05, 2010