In-Depth

Why Tape Backup Is On The Way Out

Consider three technologies to replace the inefficiencies of tape backup

• By Bud Stoddard
• 05/18/2004

Meanwhile, remarkable changes in the way businesses work, are being fueled by online and other electronic processes going on 24 hours a day. Business processes are becoming more compressed, and business activities that took days now happen globally within hours or minutes.

Inefficiencies of Tape Backup

As a result, data protection has become a critical function in an organization’s IT department, which is responsible for ensuring uninterrupted operation and immediate recoverability of all data. Faced with increasingly narrow recovery windows and "zero tolerance" for disruption, the IT staff will have no choice but to look outside the box for recovery solutions.

Considering these issues, tape backup, the solution used historically by most companies, is an increasingly archaic technology. Because tape backup has been around for years, and on the surface it may seem inexpensive, most IS/IT personnel see it as the most effective backup solution. However, for electronic data-dependant companies today, it is fraught with inefficiencies and multiple points of failure that could have a negative impact on the future health and well being of a business. For example:

• Tape backup requires personnel and human intervention, which can mean success or failure. Think about the last time Bob forgot to put the backup tape in
  
  
• Once the backup is completed, is the tape transported to a secure offsite location? The trunk of your lead computer operator's car is not secure.
  
  
• Is the data quickly and readily available in the event a restore is necessary? Does someone have to drive an hour to pick up the tape or wait hours for a courier service to deliver it?
  
  
• Equipment malfunctions are common with tape backup. What safeguards are in place to ensure a complete and accurate backup?
  
  
• Although seemingly inexpensive, tape backup can involve the high cost of human resources, hardware (tapes, drives, etc.), software (licenses, maintenance, etc.), courier service fees, and off-site storage and recovery efforts.

With their ability to most quickly and efficiently perform backup and recovery, a number of new, more technologically advanced disk-to-disk backup solutions are responding to the demands of businesses. These options include mirroring, online backup (also known as electronic vaulting), and replication.

Mirroring

Mirroring is a continuous backup method, which is the process of copying server data in real-time using a common, linked controller to another server (or servers). It provides data protection in the case of failure because data is constantly updated to designated servers. There are a number of reasons for using data mirroring, including protection from disk failure, managing planned outages, remote disaster recovery and enhanced local access to data. There are two different types of mirroring—synchronous and asynchronous.

Through synchronous mirroring, both copies of the data are updated simultaneously, keeping the data sets harmonious, but it is usually the more expensive option and can degrade performance. Asynchronous mirroring, in which the second data set can be cached, can save on costs, but does not provide coherency in the event of a problem. The main factors in selecting a mirroring type are speed, cost, and the level of data available you require.

As with anything, there are a number of risks and benefits to consider when evaluating a potential solution. The biggest advantage of mirroring is high data availability. Nevertheless, regardless of the specific type, mirroring can be costly if you add up the costs of hardware and software. In addition, because each disk relies upon a common controller, access to data is threatened when a controller fails.

Online Backup

Online backup (electronic vaulting) involves using software to automatically back up server data. The backup data is then encrypted and sent over the Internet or private telecommunication lines to secure off-site vaults. Data can be recovered on-site or remotely using vendor-provided software that accesses the data stored in the off-site vault. With this option, one gets a backup and off-site disaster recovery solution in one package.

Typically, administrator software is installed on a machine and the client agents are installed on all the servers to be backed up. Then the user selects which files and/or directories are to be backed up, backup frequency, encryption methodology, etc. From then on, the backup happens automatically according to the set schedule.

Online backup’s primary advantages are cost-effectiveness and high data availability. This is a particularly ideal solution for small- to medium-sized businesses because of its cost-effectiveness and ability to have a backup and off-site recovery component in one. A disadvantage can be high cost for large amounts of data such as the data stored at a Fortune 500 company, although the decreasing cost of storage is changing this factor.

Replication

Replication entails copying (replicating) data from one server to another across a network, whether on- or off-site. Like mirroring, this is a continuous backup method. No transfer from disk to tape is required, and the data can quickly be checked to make sure it is good. Most often, this technique is used to copy data from one site to another. For example, this option would allow a company to keep a copy of their current data at an off-site backup facility.

As with mirroring, there are two types of replication—synchronous and asynchronous. In synchronous replication, all data is delivered to both sets of storage before the client that wrote the data is aware the data has been written. Technical difficulties can occur with this method, including the long time taken to write data to the remote storage or delays when one of the storage sets becomes disconnected. With the asynchronous method, data is written to one storage device but is not sent to the other until a certain amount of time has passed, allowing for the client to be informed that the data has been written before it is passed. This can be a problem if a loss occurs before the data is replicated to both storage devices. As with mirroring, both forms are attractive because of the high availability, but replication comes at a price.

These technologies can work with existing tape or disk backup solutions or replace existing (legacy) solutions. For example, mirroring provides for data availability on multiple servers. However, to have a sufficient disaster recovery component, data must still be transported to an off-site facility, whether through online backup or traditional tape backup delivered via courier to an off-site vault.

Summary

Although these technologies are still relatively new (having come on the scene only within the last couple of years), within the IT community they have created quite a buzz and adoption is steadily increasing. In 1999, Gartner estimated that the use of data replication would grow by 50 percent annually through 2002, and that within large organizations, use of these techniques will grow to 60 percent by 2004. However, companies must closely evaluate their individual needs and objectives before choosing such a solution and should not feel that they have to put all of their eggs in one basket.

For example, one of the nation’s largest banking institutions is required to keep a fully functional off-site location where real-time data is available. They use mirroring to ensure their data is available real-time at the backup site then use online backup in conjunction. The online backup component allows for a copy of the data at a secure, off-site location should disaster strike their core and/or mirrored data sets.

Given our current environmental instability, the high value of business data, and the inability of tape backup to meet these needs, it’s no wonder that technologies that used to be seen as unconventional and experimental are quickly becoming mainstream. IDC estimates that through 2006, rapid growth will continue in the area of remote backup. Enterprise IT personnel should choose a solution according to their needs and wants. However, for most, tape backup is not a viable solution; other solutions such as mirroring, online backup, and replication should be examined. It just makes good business sense.

Bud Stoddard has over 20 years of experience in the data protection and storage industry and is the founder of AmeriVault Corp. (http://www.amerivault.com), a pioneer of online server backup and recovery for business.