What is Disk to Disk Backup?

Disk to Disk backup (D2D) utilizes a low-cost disk device that replaces tape as the initial store for backup data. The advantages of disk as data backup and storage solutions are numerous; faster backups, near instantaneous restores, no media or tape handling errors, to name a few. Typically, users will still copy backup jobs to tape as necessary to meet their disaster recovery and long-term data retention objectives.

What are the advantages of Disk to Disk backup (D2D)?

Faster backups and faster restores: By sending multiple backup streams to a disk target, users can typically get better performance than they will by using tape. Also, because the data is stored on easy to access disk, restores can be nearly instantaneous. Not all backup to disk systems are optimized for backup data streams, however, and file systems can make a huge difference in the initial and long-term performance.

Tape handling and media failures are eliminated: Since no physical tape is involved, there is no opportunity to mishandle tape or experience media failures. This is particularly important for remote sites where there is typically little or no IT support to handle such failures.

Reduce tape costs: Users will typically not eliminate their tape infrastructure entirely, but will rely on it less often, writing fewer tapes and less frequently. Thus they will save on the physical tape costs and also extend the life of their current tape infrastructure.

Make better use of incremental (and differential) backups: The trouble with incremental and differential backups is that a restore can span many tapes and be a pain in the neck for administrators to restore a volume or group of files. So, users tend to make more full backups. By using disk as the backup target, users can rely less on full backups and make better use of incrementals and differentials, easing the backup window problem more often.

What are the difficulties?

Disk-based backups have traditionally had some disadvantages:

• Backup to a SAN disk array can be faster than tape, but is not optimized for backup data performance and can be complex to manage as a backup target.
• Disks are subject to fragmentation, which further degrades performance.
• Some backup software products don't back up to file systems as well as they back up to tapes.
• Software-based compression can slow performance by as much as 50%.
• Backup to a NAS disk can be simpler but is much slower and costs more.

What is the best approach for Disk to Disk backup (D2D)?

There is more than one approach to using disk to disk backup, and one would be likely to think that a simple disk array would be the easiest and cheapest approach. But there are important advantages of using a disk based Virtual Tape Library (VTL) that will in fact make it a much simpler and cost-effective solution than a disk target.

• A disk based VTL appliance can take advantage of tape compression and/or data deduplication technology. Often, this fact alone will make the VTL less expensive on a per TB basis than RAID.
  
• VTLs are optimized for backup data streams whereas standard RAID systems are typically generalized for random IO. A disk based VTL appliance is typically 50% faster in both backup and restore than a disk target consisting of a RAID array with a file system.
• A VTL appliance can drop into a backup environment seamlessly because it can emulate an already known tape device. There is no need to change backup software or perform any kind of environment reconfiguration.
• A VTL appliance can expand seamlessly and pull new arrays into its storage pool without reconfiguring or interrupting the backup environment.

These considerations point to a disk based VTL appliance as the most efficient and cost effective approach to integrating Disk to Disk in a backup environment.

How can we help?

Overland offers two disk-based backup solutions. The REO SERIES?/a> of disk-based backup and recovery appliances provides the ultimate in speed, flexibility, features, and value for small to midsized organizations. Our ULTAMUS® RAID products offer nearline data protection.

Overland Storage’s REO SERIES Disk Backup and Recovery Appliances data backup solutions solve the challenges of storage management by providing fast, reliable data backup and recovery:

• Flexibility of configuration as a virtual tape library (VTL), standalone virtual tape drive, and/or disk volumes(LUN) – optimized for backup performance.
• Compatibility with all popular open systems or Windows-based backup software, physical tape drives or tape libraries and easy connections to Ethernet (iSCSI) or Fibre Channel networks for seamless integration into existing backup environments.
• Fast, reliable disk backup and recovery operations when configured as virtual tape, where data is written sequentially and in large blocks.
• Patented (pending) Dynamic Virtual Tape technology that automatically sizes virtual tape cartridges to match the capacity of the backup operation.
• Virtual tape library (VTL) provides user-definable virtual tape library drives, cartridges, and partitions.
• REO™ Protection OS™ embeds data protection intelligence to deliver a core set of volume and device virtualization, management and connectivity features.
• Overland REO™ Multi-SitePAC™ software automates remote backup and centralizes data management and monitoring.

Overland Storage's ULTAMUS RAID nearline storage arrays are a new breed of storage solutions that provide the advanced features, performance and flexibility to make IT department’s as efficient and dynamic as the businesses they support:

• Enterprise-class features, built-in data protection, and simplified capacity management
• Configuration flexibility through Serial Attached SCSI (SAS) architecture plus continuous availability through dual active/active controllers, fully redundant critical components, and a cableless design
• Scalability from 3TB up to drives and 96TB, making it practical to start small and add capacity as your storage capacity requirements grow

Overland Storage has data backup and storage solutions, such as disk to disk backup, to meet your data backup requirements.

Get more information

Overland Storage can help your Disk to Disk Backup needs
. Request Product Information or Contact a Product Specialist