Network Attached Storage – An Alternative To Tape Back-up

Mark Allen

June 23, 2006


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Businesses have been using tape to back up their data since the early days of computing. Tape has its limitations, but it was much cheaper than the alternatives, so its use continued.

Today, the situation is changing. The price of disk storage has come down dramatically and the performance, longevity and use characteristics of disk are far superior to tape. As a result, many businesses are looking to move away from tape for their backup and disaster recovery needs.

The key requirements of an ideal backup scheme are:

• It must be economical. Large amounts of data need to be accommodated (due to the need to keep multiple versions of the data), but in many cases the data will never be accessed. Its contribution to the company’s bottom line only comes if the data is needed, otherwise, it is an unnecessary expense.

• It must be reliable over the long term. Some data must be stored for long periods of time, perhaps decades in some situations, to meet regulatory and business needs. If that data is ever needed it must be readable and accessible. When tape sits unused for a long period, it gets brittle and is prone to breaking and data loss.

• It must be quick and easy to set up and operate. Back-up windows are getting tighter as the hours of operation increase and the amount of data continues to grow. As a result, the speed of the backup is critically important. If the backup process can be automated, human errors and costs are reduced.

• Restoring data, either individual files or a whole system, must be quick, easy and reliable. Today, it can take a long time to retrieve tapes from their offsite storage. Data on tape is stored sequentially so access to specific records can be cumbersome. Reading the tapes can be problematic if the tape is old, brittle or distorted. All this uses precious IT resources that would be better spent elsewhere. Disk storage has none of these issues.

The NAS Approach

With prices in the $2 per GB range, Network Attached Storage (NAS) systems are rapidly becoming the ideal, cost-effective back-up solution.

• Disk-to-Disk data transfer speeds far exceed those of writing to tape, so more data can be backed up in less time.

• Disk storage has greater longevity than tape, so the data is going to be there and accessible when you need it.

• Random access to data on disk saves time when trying to restore specific files.

• NAS devices are independent, complete systems that connect directly to your network so they don’t impact your other systems.

• Tape rotation schemes are possible with disk-based systems and sophisticated ones can eliminate duplicate files for more compact storage.

• For smaller amounts of data, removable disk drives mounted in hot-swap enclosures can provide a competitive alternative for offsite data storage.

• Locating a NAS system in another office and backing it up over the network provides a fast, automated remote backup. In the event of a disaster, the backup system is immediately ready to step in for rapid recovery and business continuity.

Many businesses are implementing a staged approach, where an onsite NAS provides fast backups and restores for servers and workstations. Then, to prepare for a disaster that destroys or prevents access to the primary place of business, the data is automatically replicated to a second NAS at another location. For rapidly changing and highly important data, the on-site and off-site systems can be set up to mirror each other, so that little or no data is lost if disaster should strike.

There are other reasons for deploying a NAS system. By accomplishing multiple goals, the NAS can be even easier to justify. Examples include:

• Additional end user storage. Centralized storage is easier to back up than data stored on many end user systems.

• Ideal for central repositories for workgroup or departmental data that must be shared.

• Regulation compliance, such as email retention requirements for HIPAA or Sarbannes-Oxley.

Even if you decide not to abandon tape backup entirely, you can use a NAS as a rapid staging server to gather the data from other systems quickly during your backup window. Then let the NAS feed the data to the tape unit without worrying about time constraints. This is referred to as disk-to-disk-to-tape backup.

Network Attached Storage systems are quickly becoming the preferred data sharing, management and backup solution for enterprise applications and database environments.