There is always a big question of having a system backup for a security purpose.System Backups is the best way to have our data even in times of memory corruption, memory loss, auto format, system crash down.All condition may make a loss of billion dollars to any banking system or what if a data base of share market.Just think you have saved your very important data in machine and suddenly your machine got crash down.Sometimes virus in your system may lead to reboot your machine to save it from major damage in that cases too data backups helps a lot to restore your important data after rebooting.
To avoid loss of our important data in such conditions data backup will help us to retrieve our important data.This is mainly done based on the importance of the data and the amount of data to be backed up.We also have to have a check for the available space to store.Some common ways to have a system backup are as follows-

a) Tapes can be used as back up storage devices.

b) Optical devices such as -i]DVD's ii]CD's
can be used too as data storage devices.

c) Flash memories (USB Drives, Portable Hard Drives) another device which can also be used for storage for the data that we need to have a backup.

d) Online services, are one another effective and hitech way to have you data backups.These are paid services provide by some sites specially working and providing such services only.For example Xdrive, allow users to upload their files to a server for safe keeping. Although it may be convenient to have the data available wherever an internet connection is available, there are a few limitations.

Tapes are now a days out dated so they can be used as a backup device but will give less space for storing.Optical devices like CD's and DVD's can also b used but they are useful when data is small amount even then there are chances of them getting corrupt by scratches. Flashes memories too have problem of less space in that case handy hard drives will prove helpful as well as they will allow us to store large amount of data too.