At Kroll Ontrack we have recovered data for many customers who were using an internet backup service and assumed that their data was totally protected. They were caught out by the way these backups work, they did not realise that this backup method can have serious limitations, which resulted in them loosing valuable data.
Backing up data via the internet using a backup service is becoming a common way of protecting data from the causes of data loss. The method is very effective and will protect against the most common causes of data loss, a hard drive failing and a computer being lost or stolen
However, there are two causes of data loss that internet backup services will not fully protect against and therefore put your data at risk of being lost. These limitations have caught out many of our data recovery customers, both home users and large commercial businesses.
If you use an internet or remote backup service for your PC or mobile device every time you write a document or add a photo it sends a copy via the internet to the backup storage location (often called “the cloud”). This normally happens automatically every time you make a change (and click save in some instances). If the computer crashes or fails the most data you can expect to lose can be just a few minutes of work or a few files. Everything should have been synchronised to the cloud backup service.
This sounds good until you realise the software will also synchronise every deletion or incorrect modification you make to your data and this makes your data vulnerable to being lost. For example, if you make a mistake and want to retrieve a deleted file that has also been deleted from the recycle bin, it is likely to have been deleted from the online backup too. At Kroll Ontrack, one of the most common data recovery requests we receive are for files that were deleted by a user some time ago as they were thought to have no value or were deleted by mistake. The deletion had then been replicated to the backup so there was no backup copy.
A more catastrophic version of this type of data loss is when the older version of a file overwrites the newer version, i.e. the system synchronises the file the wrong way. This is particularly common when you change to a new computer.
Tip: For the first synchronisation you want to sync from the cloud to the computer and not the other way round.
Many internet backup services have started offering protection against incorrect edits or deletions by saving previous document versions. However, for this feature to provide protection you need to realise what you have done almost immediately after it happens, i.e. within 30 days if you are using Dropbox.
It can be several months before you realise you deleted the wrong file and by this time it may be too late to retrieve the file from the cloud backup service.
Data corruption and in rare cases, malicious damage
We see this cause mostly when there is an interruption to the power supply at the same time that the computer is writing data to the disk drive. Power interruptions sometimes cause the hard drive to lose track of its write location and then starts to writes data to the wrong place on the disk when the power is restored. This causes data corruption, and except for severe cases, this may not be immediately apparent. This result is the backup software replicates the corruption, therefore making the backup corrupt too.
The most catastrophic case that Kroll Ontrack engineers were involved with was due to a mistake made by an IT maintenance engineer. He was making changes to a company’s computer storage systems and he forgot to turn off the automatic backup software before making the changes. After the changes were made, access to a large quantity of valuable data was lost. Then, due to the backup software not being turned off, all the changes were automatically replicated to the backup site. Fortunately Kroll Ontrack engineers were able to recover the missing files.
Recommendations to protect your data
- Keep a backup and an archive. Remember, you are never fully protected unless you have at least two backups.
- For day-to-day backups, an internet cloud-based backup is probably one of the best and most convenient backup methods. It will protect data against the most common causes of data loss.
- Periodically, make another backup of your data, or just your most important data if this is not feasible.
- Keep multiple dated copies of your data. These can be kept on an external hard drive, or even better, on multiple storage media.
- For businesses using syncing-type backups this limitation is protected against by making a separate secondary backup or archive of at least your most important and valuable data. These archives may go back several years, and in some cases are legally required to do so.
Many other devices other than personal computers or laptops sync data. Most commonly they are mobile devices for email, apps, music and calendars. For this blog I have limited the discussion to computers and the backing up of computer generated files such as documents, photos or raw data – the data that is created by you and cannot be easily recreated if it is lost.