A back-up or reserve copy duplicates the information found on a data carrier or in an application. These copies are made preventively to safeguard and restore important information in case data on the original carrier becomes lost or damaged. The term ‘back-up’ is mostly used for data on computer hard drives, but information from other carriers – such as SIM cards, database management systems and even non-electronic sources like address books – can also be backed up.
How can files become damaged or lost?
- a hardware fault such as a defective hard drive or failing electronics (possibly temporary as a result of overheating);
- human error such as accidentally deleting or incorrectly editing a file;
- programming errors or bugs in the original software or updates;
- changes caused by malware, such as viruses or deletion by a trojan horse.
Everyone knows they should, but not all organisations make good back-up copies. Even just a limited budget, knowledge and resources can go a long way.
But because there is no solution that works perfectly in every situation, this section aims to highlight some basic rules, principles and pitfalls when creating a back-up strategy.
Map out your files
It’s best to gather all your files together before starting to back them up. This allows you to determine which files are important and/or difficult to replace from the outset. Important, irreplaceable information deserves the greatest care, whereas files that can be replaced easily might not need a back-up at all.
Save multiple versions
If it turns out that a file was already deleted a week ago, a back-up from yesterday isn’t much use. It is therefore best to perform a new back-up every day, and to save those from the start of every week and month.
And even this isn’t necessary if you perform an incremental back-up, which records a full copy of your data all at once and only adds new or modified files, also making it easy to retrieve a file’s history so you can see what it looked like a day or month ago. This kind of back-up software is provided as standard in recent operating systems now: Windows Backup or Time Machine for macOS enables you to easily configure incremental back-ups on a network or external hard drive.
Save a copy at an external location
Saving a single copy of your data as a back-up isn’t sufficient; in the event of a fire or burglary, you could lose everything. You should therefore save an extra back-up at an external location.
Scenario 1: Local + automatic centralised back-up + take a hard drive home with you
You make an automatic back-up on a network drive at your office. You also make a back-up on an external hard drive that is kept somewhere else.
- one-off file transfer
- monthly back-up
- stable network
- network drive
- extra hard drive
- you might forget to take your hard drive to the other location
- you don’t have access to colleagues’ files
Scenario 2: Local + centralised back-up + external back-up
A classic solution is to have a centralised server that saves your data at an external location. After the initial ICT work, this requires less maintenance than you might think and doesn’t cost very much.
- one-off major configuration
- annual server costs
- annual ICT costs for server management
- one-off cost to install the back-up
- if something goes wrong, you need someone who understands the issues
Scenario 3: Cloud services
As an alternative to the external hard drive, you can use cloud services such as Dropbox or Google Drive, which are often free and ideal if you don’t have much digital content. But they can also be quite expensive if you have a large audiovisual collection or manage an audiovisual archive. One solution could be a service such as Amazon Glacier.
- good internet connection (doesn’t work if you are on a train, for example)
- expensive per GB
- you still need to make your own back-ups
- the control is out of your hands
So be careful: cloud services do not constitute a fully-fledged back-up. A distracted colleague could still accidentally delete a file from cloud storage, in some cases losing it irrevocably. Cloud services should therefore be combined with another type of storage such as a central server, NAS (Network Attached Storage) or external hard drive.
Test and document
It’s important to document the restore procedure, so you don’t lose much time if fate strikes. Make sure you have a document that explains where your files are and how you can restore them. If necessary, document how to re-install all the software and load emails back into your email software/application.
Please note: regularly check that back-ups are complete, and test whether the data can indeed be recovered. You should occasionally perform a random sample with several files as a minimum. If it works, you can rest assured.