While the adoption of virtual technologies is accelerating, data protection tools have not kept pace. There is a gap in protection between physical and virtual markets, and some organizations are now turning to "on-demand" online backup-and-recovery services to fill this gap. This software-as-a-service (SaaS) model, which leverages disk-to-disk backup-and-recovery technology, is an option that can optimize data protection in virtual environments, and offer fast recovery times in the event of a data disruption or disaster.

The primary challenge in delivering backup-and-recovery SaaS to virtual machines is ensuring comprehensive disaster-recovery protection for all major operating systems, applications and files stored on those machines, via the Internet. SaaS has the ability to provide complete data protection, without requiring large upfront investments in infrastructure.

Integrated hot backups afforded by backup-and-recovery SaaS solutions ensure tight integration of the backup-and-recovery SaaS solution, ensuring that the operating system, application or data is still accessible to the user, and no downtime is required on the part of the virtual machine to complete the backup process.

Detecting block-level changes at the source, and only backing up those changes on a daily basis is another benefit of backing up virtual environments via a backup-and-recovery SaaS. For example, a virtual server hosting 10 million banking records may only experience 200,000 additions, changes or deletions on any given day–or a 2 percent rate of change. Using SaaS, a block-level backup records only those changed records, rather than the entire database, for greater efficiency.

Disk-to-disk versus tape

The next step in SaaS backup and recovery is to compress the data. Typical DB2 databases compress well, with ratios of 8:1 and higher reduction in data size. Using a 2 percent daily rate of change and a compression factor of 8:1, a 10-TB virtual system will only transmit 25 GB of data, which can be moved over a 10-Mbps ISP line in about five hours. Backing up only the compressed changed blocks of data improves network performance, decreases the backup window and lowers overall storage footprints.

In the case of tape-based solutions, tapes need to be moved offsite; media should be maintained for as long as backups need to be available; tape media should be refreshed to maximize recoverability; and backups typically need to be migrated from older to newer formats every three to five years. All these steps increase the total cost of ownership (TCO) of a tape-based solution.

A pure disk-to-disk solution does not experience these problems, particularly for SaaS vendors who are storage-agnostic. Additionally, a disk-to-disk solution comes with a smaller storage footprint.

A typical tape backup cycle requires six daily, five weekly and 12 monthly backups. For a 10-TB system, this results in 230 TB of tape media. With a backup-and-recovery SaaS system, the initial backup is compressed to 1.25 TB, with the remaining 23 versions needing 25 GB (daily rate of change), resulting in a total of nearly 2 TB of storage. Therefore, a disk-to-disk system is 200 times more space efficient than tape-based systems.

The final step in the SaaS backup-and-recovery process is encrypting the data prior to transmission and then keeping it stored in encrypted form on the back-end storage media. These systems should support military-grade, typically NIST-certified AES 128-bit encryption, or higher.

Because SaaS backup and recovery is an automated electronic process, it provides companies with additional benefits at almost no cost. To improve data recovery in virtual environments, database journaling can be established, with the SaaS backup and recovery configured to back up the journal receivers frequently throughout the day. If the system goes down at 3:45 p.m., an entire day’s work will not be lost, only the activity that took place since the last journal receiver was backed up.

What to look for

When considering a backup-and-recovery SaaS provider, here are a number of considerations to keep in mind:

Ensure the SaaS provider offers a true disk-to-disk solution and not disk to disk to tape. With disk to disk to tape, after a few backups the disk fills up, requiring users to archive some data from disk to tape.
Ask what certifications the SaaS provider has (e.g., SAS 70 Type II) and how the provider helps meet regulatory compliance (i.e., Sarbanes-Oxley, HIPPA) obligations.
Ensure the SaaS provider supports a wide variety of platforms, so all backups across all servers in the environment can be consolidated to a single solution.
Ask the provider what levels of security are available; the vendor should offer secure end-to-end protection with no hidden "back door" access.
When data resides in the hands of a third party, request a guarantee that it be stored in physically secured locations with multiple ISP and power backup systems. Also inquire about 24/7 customer support.
Ask about alternate recovery options. What will the provider offer if online recovery is not possible? Are the alternatives offered by the vendor viable for your business?
Some disk-to-disk management consoles do not work well through firewalls or VPNs, making implementing the solution at remote offices difficult. Look for a system that can be easily and securely managed from a central location.
Ask the SaaS provider about scalability. Will the solution meet your needs for the next 18-24 months?

Richard Heitmann is vice president, product management, for EVault, Emeryville, Calif.

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