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Backup appliance: Backup software and hardware in one box

By Chris Evans

The backup appliance is an option gaining in popularity as a means of data protection, especially for SMBs and for branch office use.

A backup appliance comprises a backup application preloaded onto a hardware device with built-in storage media. Traditionally, IT organisations have put together their own backup solutions using a backup application, a server and target media. This method provides the greatest level of flexibility but requires staff members to have in-depth knowledge of hardware components and the backup software.

An appliance makes initial deployment and ongoing operations simpler and removes the need for specific training and backup skills. As a consequence, a backup appliance is well-suited to organisations that don’t have dedicated storage teams. Backup appliances are specifically designed for backup traffic and to make the best use of memory, processor and I/O resources.

Backup appliance features

Not all hardware backup products on the market can be classed as backup appliances; some products are simply disk storage arrays that integrate with common backup software. In this discussion we will look at products that provide the hardware and the software as an integrated package.

A good example is the NetBackup 5200 Appliance from Symantec. The 5200, which supports data deduplication, is prepackaged with NetBackup 7 and 32 TB of disk storage. This prepackaging removes the need for the customer to be concerned with the deployment, configuration and ongoing management of an OS on the appliance.

The following points should be considered when selecting a data backup appliance product:

• Vaulting: An effective backup strategy should encompass on-site and off-site backups (or vaulting), so look for appliances that provide for removable media. The Idealstor SATA Backup Appliance line of products, for example, uses removable hard drives for vaulting rather than traditional tape for off-site backups. Most solutions use tape for off-site vaulting, however, and you should consider tape cartridge capacities to see how they fit with the volume of data to be backed up.
• Security/encryption. In any backup scenario, encryption is important in any solution that includes media vaulted off-site. Check to make sure any removable media can be encrypted to industry-standard protocols and strength.
• Connectivity and throughput: Backups will run only as fast as network connectivity allows. Look for appliances that offer fast connectivity (a minimum of 1 Gigabit Ethernet) and multiple connections. When comparing the performance of appliances, look at throughput figures that are usually expressed in terabytes (TB) per hour.
• Management: A key benefit to installing a backup appliance is simplified management. Look for Web-based management GUIs that remove the need to deploy software locally. Arkeia, for example, provides a Web-based management GUI for its range of backup appliances. Meanwhile, Dell’s PowerVault DL Backup to Disk appliances are managed through a Web GUI that simplifies configuration of the underlying CommVault Simpana or Symantec Backup Exec software.
• Licensing: Client licensing varies from vendor to vendor across the range of backup appliance products. For example, the Tandberg AccuVault 1U 8 TB model comes standard with 20 client licenses but can be increased to a maximum of only 40 clients, whereas Revinetix’s Sentio products have no client licensing restrictions and are based only on backed-up capacity. Look carefully at your licensing requirements to ensure a product will work for your environment.

Many vendor offerings provide advanced features.

Data deduplication

Data deduplication is a feature offered in almost all backup products today. Data deduplication identifies and removes duplicates of identical pieces of information within the backup stream and can shrink backups at rates of 10-to-1 to 20-to-1 or more. For performance reasons, this is usually performed after the backup has completed and is done by indexing unique copies of data either at the block or file level.

Data deduplication works best with disk solutions and is well-suited to backup appliances. Users should bear in mind, however, that because of the data reduction available with data deduplication, it is possible to hold many more backups on the same physical media (disk or tape) than is otherwise possible and that a failure in that media could result in a loss of all backup copies.

Branch-to-core consolidation

In organisations that have branch offices with dedicated IT equipment, backups can be deployed effectively using an appliance. As an additional security measure, those backups can also be replicated to a main or core data centre.

Such centralisation of backups provides greater resiliency and security compared with off-site media vaulting. The StorServer Backup Appliance, for example, enables data to be consolidated into a central data centre and restored elsewhere using its Instant Recovery feature. Of course, branch-to-core replication also requires high-speed network connectivity and so may not be suitable in all locations.

Virtual appliances and the cloud

In this article we have discussed the concept of hardware and software bundled together as a backup appliance. Some vendors -- such as PHD Virtual , Zmanda and Arkeia -- offer virtual backup appliances. These run in virtual machines and offer the same level of functionality as their physical counterparts. We can expect to see this option gaining in popularity as the number of purely virtual server deployments increases.

Most backup applications and therefore also backup appliances now integrate on-site backups with cloud-based backup services. Using cloud services provides the ability to create an automatic off-site copy with a cloud service provider that can be restored to the customer’s data centre when required.

Backup appliances can reduce the complexity and effort involved in deploying backup and are a great tool in a data protection strategy. They offer features equivalent to existing standalone backup applications and can act as a stepping stone to cloud-based backup service offerings. Appliances may not suit all IT organisations, but we will see their adoption increase in the coming years.