It is easy to lose data. You can accidentally delete a file, a drive can be corrupted, or broken, you can lose or break physically portable memory (and devices) - Flash memory sticks rarely survive the washing machine, and then there is the risk from viruses, hacking and ransomware. Losing customer data can not only cost you business, but can lead to large fines under the Data Protection Act (UK) and GDPR (EU).
To protect against this, you need to back up your files. A back up is simply a copy of data and files. Back ups should be made on separate storage drives or different servers to avoid risks of drives dying and wiping out the back up copy at the same time as the main version. Backup drives, disks or even magnetic tapes (going old school) are often kept in a locked, fireproof safe at a different location - an off-site backup. Many companies now back up over the internet to the cloud to achieve this - remember the cloud is really just someone else's servers.
Image Credit: techmsg, via Flickr, CC-BY-2.0
There are two main types of backup:
- Full back up
- This makes a copy of every file and piece of data, every time it is run
- Incremental back up
- This makes a copy of files that are either new since the last full backup, or have changed since the last back up
An incremental back up is quicker than a full one as it has to copy less data.
Organisations often employ both types. Having a regular,but less frequent full back up to make sure there are copies of every piece of data. This is then supplemented by frequent ,usually daily and in the cases where there are lots of frequent changes, and data is critical, such as a bank sometime much more often, maybe every minute.
This article is interesting insight into how US banks help each other with back ups to avoid banks crashing and losing all customers data
It is an advert for a US company, but it makes the point.