Backup Planning
20 January 2012
Backup is a bit like car insurance – you resent paying for it but, every once in a while, you’re very glad you have it. The difference is that there is no legal requirement to have backup so, if you chose not to have it, you can find yourself losing everything
Some years ago a client had a break-in in which their server was stolen. To make things worse, the backup tape was still in the drive, and the drive disappeared with the server. They had four magazines going to press that month. The loss of that data might lose them four contracts and could have meant the end of the company
Fortunately they backed up every day, each backup was to a separate tape, and the other tapes were locked away in a safe. This wasn’t a lucky break – the backup system was designed to have multiple, redundant backup media and to backup daily. We sourced a new server, reinstalled the relevant software, restored the backup and in less than 48 hours they were working normally again with the loss of only eight hours work
A simple story – what can we conclude from it?
- The backup system was backing up the correct files
- The backup system offered enough redundancy to recover from a worst-case situation
- It was possible to replace the hardware in a short enough timescale not to affect the client’s business
- It was possible to restore the files quickly enough not to affect the client’s business
- The backup system met the needs of the client
- The backup system was fit for purpose
Being fit for purpose is key here: whatever backup system you choose must meet your criteria and suit your business. To ensure this we break down backup into two stages
- Backup Policy
- Backup Strategy
Backup Policy defines what the business needs. It states which files are to be backed up, how often, whether backups are kept offsite and what the data retention policy is – ie, for how long old versions of files are kept. Properly written, a backup policy will ensure that the correct files are backed up in such a way as to safeguard the business in the event of data loss. The Policy should be written by the company, based on their needs and their experience
The Backup Strategy defines how the policy will be implemented. Backup systems vary a lot in scale and complexity. Some companies require Terabytes of storage, some just a few Gigabytes, and this makes a huge difference to how quickly the backup can be performed, what media to use and how offsite backup can be provided. Working out an appropriate strategy is a task for an IT professional
Given an accurate policy it’s possible to develop and implement a strategy relatively quickly. The stumbling block usually is whether the strategy falls within budget. Frequently it’s not and this can lead to compromises being made. Whether these compromises are acceptable goes back to the policy, so either rewrite the policy to accept the compromises and bring the system within budget or increase the budget to satisfy the policy and your requirements
Whatever you do, don’t compromise the strategy to save money. Otherwise, when the backup tape that goes missing is your only backup, you’ve lost your data. Not only that but your backup budget has been completely wasted