From Wikipedia, the free encyclopedia
A remote, online, or managed backup service is a service that provides users with a system for backing up and storing computer files. Online backup providers are companies that provide this type of service.
Online backup systems are typically built around a client software program that runs on a schedule, typically once a day. This program collects, compresses, encrypts, and transfers the data to the remote backup service provider's servers. Other types of product are also available in the market, such as remote continuous data protection (CDP).
Providers of this type of service frequently target specific market segments. High-end LAN-based backup systems may offer services such as near-realtime transaction-level replication or open file backups. Consumer online backup companies frequently have beta software offerings and/or free-trial backup services.
Most online/remote backup services came into existence during the heyday of the dotcom boom in the late 1990s with the exception of a few early pioneers like industry originator Rob Cosgrove, CEO of Remote Backup Systems. While the initial years of these service providers were about capturing market share distributed among the top few providers, the large industry players took cognizance of the importance and the role that these online backup providers were playing in the web services arena and M&A activity has become quite predominant in the last few years. Today, most service providers of online backup services position their services using the SaaS (software as a service) strategy and its relevance is predicted to increase exponentially in the years to come as personal and enterprise data storage needs rise. The last few years have also witnessed a healthy rise in the number of online backup providers with them existing independently as also as part of a business unit of a larger industry behemoth.
 Typical features
- Opened file backup
- The ability to back up files that are frequently left open, such as Outlook files (*.pst) or SQL database files. This feature allows IT administrators to run backup jobs at any time of the day, not requiring server down-time. Most enterprise online backup products support an add-on for this. Higher-end products may support this natively.
- A multi-platform backup service can back up multiple platforms such as the various flavours of Windows, Macintosh, and Linux/Unix.
- Network backup
- A backup service supporting network backup can back up multiple computers , servers or Network Attached Storage appliances on a local area network from a single computer or device.
- Some services offer the capability to back up both data at the primary site and data located at remote offices and branch offices, in a relatively seamless manner.
- Continuous backup - Continuous Data Protection CDP
- Allows the service to back up continuously or on a predefined schedule. Both methods have advantages and disadvantages. Most backup services are schedule-based and perform backups at a predetermined time. Some services provide continuous data backups which are used by large financial institutions and large online retailers. However, there is typically a tradeoff with performance and system resources.
- Online access to files
- Some services allow you to access backed-up files via a normal web browser. Many services do not provide this type of functionality.
- Data compression
- Data will typically be compressed with a lossless compression algorithm to minimize the amount of bandwidth used.
- Differential data compression
- A way to further minimize network traffic is to transfer only the binary data that has changed from one day to the next, similar to the open source file transfer service Rsync. More advanced online backup services use this method rather than transfer entire files.
- Transfer encryption
- Encryption to prevent interception of data. This does not mean that the data will necessarily be encrypted during storage.
- End-to-end encryption
- Encryption of data at the client. The encrypted data is then transmitted and stored on the server. This requires a client-generated key, and precludes data recovery should the key be lost. Depending on implementation, it may also preclude certain optimization techniques (such as recognition of common operating system files which don't need to be stored multiple times, and removal of duplicate user files across different users —'deduplication').
- Bandwidth usage
- User-selectable option to use more or less bandwidth; it may be possible to set this to change at various times of day.
 Cost factors
Online backup services are usually priced as a function of the following things:
- The total amount of data being backed up.
- The number of machines covered by the backup service.
- The maximum number of versions of each file that are kept.
- Data retention and archiving period options
- Managed backups vs. Unmanaged backups
Some vendors limit the number of versions of a file that can be kept in the system. Some services omit this restriction and provide an unlimited number of versions. Add-on features (plug-ins), like the ability to back up currently open or locked files, are usually charged as an extra, but some services provide this built in.
Most remote backup services reduce the amount of data to be sent over the wire by only backing up changed files. This approach to backing up means that the customers total stored data is reduced. Reducing the amount of data sent and also stored can be further drastically reduced by only transmitting the changed data bits by binary or block level incremental backups. Solutions that transmit only these changed binary data bits do not clog bandwidth by transmitting the same file data over and over again if only small amounts (ie a date change or different address in a word document)
 Advantages of remote backup
Remote backup has advantages over traditional backup methods:
- Perhaps the most important aspect of backing up is that backups are stored in a different location from the original data. Traditional backup requires manually taking the backup media offsite.
- Remote backup does not require user intervention. The user does not have to change tapes, label CDs or perform other manual steps.
- Unlimited data retention.
- Some remote backup services will work continuously, backing up files as they are changed.
- Most remote backup services will maintain a list of versions of your files.
- Most remote backup services will use a 128 - 448 bit encryption to send data over unsecured links (ie internet)
- A few remote backup services can reduce backup by only transmitting changed binary data bits
 Disadvantages of remote backup
Remote backup has some disadvantages:
- Depending on the available network bandwidth, the restoration of data can be slow. Because data is stored offsite, the data must be recovered either via the Internet or via tape or disk shipped from the online backup service provider.
- Some backup service providers have no guarantee that stored data will be kept private - for example, from employees. As such, most recommend that files be encrypted before storing or automating this process.
- It is possible that a remote backup service provider could go out of business or be purchased, which may affect the accessibility of one's data or the cost to continue using the service.
- If encryption password is lost, no more data recovery will be possible. However with managed services this should not be a problem.
- Residential broadband services often have monthly limits that preclude large backups. They are also usually asymmetric; the user-to-network link regularly used to store backups is much slower than the network-to-user link used only when data is restored.
 Managed vs. Unmanaged Online Backup
Some services provide expert backup management services as part of the overall offering. These services typically include:
- Assistance configuring the initial backup
- Continuous monitoring of the backup processes on the client machines to ensure that backups actually happen
- Proactive alerting in the event that any backups fail
- Assistance in restoring and recovering data
 See also
- ^ Online Backup Services
- ^ Guide to Online Backup
- ^ Why Online Backup?