Managing your company data poorly can have serious consequences. No matter your business or data size, it’s imperative you have a robust data backup strategy in place. You need to know the risks, the impact to business, and the associated costs. And you can’t design a strategy to cover that, until you’re aware of the essentials of data backup.
Backups or Archives? What’s the Difference?
A backup is a copy of your live production data, created at a specific point in time, that you can revert to in the event of either a small data loss, or a disaster level event. The data produced by backups is safest when stored both locally (for quick and easy access) and remotely (referred to as offsite). The latter being required in the event of disaster recovery.
An archive is a specific data backup, taken at a specific point in time, that is then safely stored as part of a long-term solution. End of financial year for instance. These archives are stored at a secure facility in offsite locations, often for several years. They can then be called upon for various reasons, such as taxation requirements, or legal criteria.
What Type of Backup Is Best?
The two types most commonly used are partial, and full. Any sound backup strategy utilises both of these, and often.
Full backups. This is a backup of all the software, programs, and data on your systems. Also referred to as a snapshot. It should be performed at least once a week. The best backup solutions will copy entire servers, doing so in such a way that they could be fully restored in the event of a total disaster.
Partial backup. Linked to an existing full backup, a partial backup copies only the files that have been changed or added since the previous partial backup. Depending on the backup software, partials can even be run hourly. But at an absolute minimum, partials should be run once a day. Partial backups can take the form of either ‘differential’ or ‘incremental’.
Differential: Backs up files that have been modified since your last full backup session. For instance, if you ran a full backup on Saturday, and then a differential on Monday, only the files that have changed since Saturday will be backed up. Those changes will then be appended to the Saturday full backup. This means you cannot rely on Saturday’s data as some form of “point in time” backup archive. The time taken to perform a differential backup is faster in comparison to a full, as the data being backed up is much less.
Incremental: Once a full backup has been run, subsequent incremental backups can then be run at specific points in time, day or night, weekly or monthly. Like a differential, only the files that have been added or changed will be backed up. But, unlike a differential those changes are stored as a separate incremental backup file and NOT rolled back into the original full backup. This means if you ran a full at 9am Monday, and then ran incremental backups every three hours after that, you would have the ability to go back to a specific point in time. But there’s a downside. The older your original full backup file is, and the more incremental files you have, the more likely the risk of a file becoming corrupt. Potentially, depending on your chosen backup platform, a single corrupted incremental file could mean disaster for your entire backup file chain. Also, when carrying out restores, the sheer number of files involved in your chain will impact upon your restore times.
Backup Frequency — How Often?
To answer this, you need to know your data retention requirements. Are there any legal items you will need to satisfy that would dictate how long you keep your backed-up data for? Once that is known, you can then begin to create backup data ‘sets’. Groups of full/partial backups, and ‘points in time’ backups. Generally speaking, if retention requirements are not a concern, the following can apply.
1. Perform a full system backup of your entire business/company data and systems at least once a week. Append this backup with partial backups that run at least once a day. Store this backup set for at least four weeks, deleting the oldest as you go.
2. Perform a full system backup of your entire business/company data and systems once a month. Do not append this data with partial backups. This is a ‘point in time’ backup. Keep this set for at least three months, deleting the oldest as you go.
3. Perform a full system backup of your entire business/company data and systems once every six months. Do not append this data with partial backups. Keep only one copy of this backup, replacing it every six months.
4. Perform a full system backup of your entire business/company data and systems once a year. Store this data safely for whatever period of time your retention requirements might suggest.
We strongly suggest that, as part of your strategy, you examine in detail the importance of your business data. This will help you make informed decisions with respect to what you back up, and how often. Once you understand what and how often, a managed backup solution from a reliable MSP will help you a potential data disaster.