Cyber Security: Backup media

Backup media
Depending on the amount of data you need to backup, a range of technologies are available:



Optical storage
Optical storage is the same technology used for CDs, DVDs and Blu-Ray.

The most common technology for optical storage is writeable DVD standards including DVD-R, DVD+R, DVD-RW, DVD+RW and DVD-RAM. Most of these DVD formats can store 4.7 GB on a single disc, although newer, so-called, dual layer discs and drives can store twice that. Blu-Ray technology offers 25 GB and dual layer (50GB) formats with three layer 100GB discs, although they are expensive.

Advantages

• Optical drives and media are extremely cheap and widespread. Most computers have an optical drive or can accept a USB driver and the discs can be bought in supermarkets.
• There are a large number of manufacturers, so there should be no problem with future supplies of discs.
• More modern optical disc technologies (such as Blu-Ray) also support most older types of disc such as DVD and CD.
• The media is relatively small. Large amounts of data can be stored in a very small space.
• The media is robust. Discs can be posted and are able to survive regular use or being dropped. They are resistant to extremes of temperature and humidity, and immune to strong magnetic fields.

Disadvantages

• Optical drives are relatively slow compared to hard disks, especially when writing data.
• There are a large number of types of disc (especially recordable DVDs). Some of these discs are not widely supported.
• Their capacity is relatively low compared to hard disks. A 1TB hard disk is commonplace on modern computers, so it would take more than 200 DVDs to make a complete backup of the disk. Consequently, DVDs might be best suited to making backups of key data.

Magnetic disks
The magnetic hard disk at the heart of most computers can also be used as a backup device. Most PCs have sufficient internal space for a second hard disk that can be devoted to backups, or a relatively cheap external hard disk can be connected to a USB or Firewire port on a computer.

More expensive disks can be connected directly to a network using Ethernet or wi-fi in which case they are known as Network-Attached Storage (NAS). Disks can be made more resilient to failure by combining several disks together with copies of data stored on multiple disks so that even if one copy is damaged or the disk fails, it is not lost forever; the most common type of this ‘redundant’ storage is called a Redundant Array of Independent Disks (RAID).

Advantages

• Disks are relatively cheap and capacities are growing rapidly.
• External hard disks can be easily moved between computers.
• There are many disk manufacturers, all of whose products can be used in almost any computer.
• There are a large number of back-up programs designed to be used with hard disks. Many external disks are sold with applications to ease the back-up process, or offer a ‘one touch’ back-up button.

Disadvantages

• Hard disks are fragile and easily damaged if dropped or exposed to extremely high temperatures or magnetic fields.
• If hard disks are used once to make a back up then archived, the replacement cost is much higher than for tape or optical media.

Solid State Disks
Solid State Disks (SSDs) are storage devices that can store data in memory chips without the need for a power source. The name is somewhat misleading because these devices don’t actually contain physical disks. They can be commonly found in the USB memory sticks used for sharing files between computers. As the technology has advanced to increase the storage capacity of SSDs they are now being used in laptops and mobile devices as substitutes for magnetic disks.

Advantages
SSDs have the same advantages as magnetic disks when compared to optical storage technologies. Some additional advantages are:

• SSDs are more robust and are unlikely to be damaged if dropped or exposed to magnetic fields.
• It is possible to read and write data from SSDs much faster.
• There is no noise produced when SSDs operate because they have no moving parts.

Disdvantages

• SSDs are more expensive than equivalent capacity magnetic disks.
• At the moment, the maximum capacity of SSDs available on the market is 1TB although this will increase as the technology advances.

Remote backups
Large businesses and organisations insure themselves even further against failure by storing backups away from their centre of operation.

In the event of a disaster, there is much greater likelihood that they can return to normal operations within a short period of time – after all, it is much easier to buy new computers than recreate all of the records.

Offsite backups
Specialised companies offer specialised facilities where companies can hire storage space or machinery to hold backups. These offsite facilities might be nothing more than an extremely secure vault where tapes or disks can be deposited; but increasingly they are large server farms connected to extremely high-speed networks. Users can copy files to these servers as if they were part of their own network; the only bottleneck is the speed of the network between the offsite facility and the user.



The UK’s largest such site is Telehouse UK in London’s Docklands which has partner sites in the United States and Japan. The London facility covers some 45,000 square metres and is used by over 700 large companies and internet service providers.

Backing up to the Cloud
For many years, offsite backup was restricted to organisations which could afford relatively large monthly fees. Cloud technology allows anyone to have offsite storage, and in many cases a certain amount of storage is completely free. Most cloud services are designed for convenience, to allow users to share files between computers, and with other users, rather than specifically as backup services, but they can also offer you some additional security (especially when you encrypt files before putting them in the Cloud) if your computer is stolen or stops working.



One strong word of warning if you do use the Cloud as a backup, with only a few exceptions, these services will not protect you if a file is deleted. Most Cloud services are synchronised – that is, when a file is deleted on your computer, the copy on the Cloud server is either immediately, or very shortly afterwards, also deleted.

Cloud backups are obviously limited by the bandwidth of your internet connection. If you have a slow uplink (that is sending data to the Cloud) you may not be able to make backups of all your data in a reasonable amount of time. Instead you might have to prioritise which data is backed up to the Cloud and which is stored locally.

Cloud security
Unless you take further steps, once data is stored in the Cloud you can no longer be sure that it is entirely secure from prying eyes. Most suppliers have policies claiming that your data will be secure, but they cannot provide absolute insurance from attackers, as experienced by some celebrity users of Apple’s iCloud service in 2014. You can read more about this incident, if you are interested, via the link at the bottom of this page.



Some businesses have policies forbidding employees from storing information in the Cloud as it may not be secure, or it may be stored outside the legal protection of the company’s country of origin.

Using encryption to scramble the contents is the only way you can guarantee that your data is safe in the Cloud.