Your local computer technicians

More than a backup

More than a backup

11th March, 2011

Computer Troubleshooters – Parramatta recently attended a seminar where the demonstration of a recovery of a failed system took about 6 minutes to become operational again with a loss of no more than 15 minutes worth of data. This solution does raise a number of interesting questions for small businesses.

  1. What is the main purpose of a backup?
  2. How much data are you prepared to loose when you recover?
  3. How quickly do you want to recover?

What is the purpose of the backup?

Is the purpose of the backup to be able to recover a version of a file that was saved 20 minutes ago or earlier that day? Maybe you want to recover a file that was backed up at the end of the previous day or do you want to reload the whole system without installing the individual applications and data?

The answers to these questions are important as it will govern the choice of software. If what is important is to recover as of the end of the previous day then there is a lot of software that can achieve that requirement. If however what is important is to recover to a version at a particular time then the field is much reduced however this class of backup application will also provide a backup as of the end of the day, week, month etc. and can also be used to restore the whole system.

How much data are you prepared to loose when you recover?

This is an important question that needs to be answered. If the data is coming from a busy office where a short period of time generates a lot of data change or creation, then it could be an expensive exercise to have to recreate this data if you only took backups daily. The answer to this question governs the frequency of how often a backup is taken.

How quickly do you want to recover?

Really what is being asked is how long your business can survive before being impacted by a system failure? If the answer is I can wait a few days because my computer system is not critical and I can run with manual processes for a few days then so be it. However if you want to achieve recovery in the shortest amount of time e.g. 10 minutes, then the appropriate software must be selected, together with the strategy to achieve this.

Our preference

Using Storagecraft’s ShadowProtect application, a scenario of where the least amount of data is lost together with recovery in the least amount of time is achievable. Referring to diagram below, the server is backed up to the NAS using ShadowProtect using a strategy called continuous incrementals. At the same time Storagecraft’s ImageManager is able to replicate the stored images on a secondary device or to the cloud providing the management of an offsite archive or a repository that could be taken off site. It is also ImageManager that handles the management of the incrementals, including their verification, consolidation and notification all based on policy settings.

Backup Diagram


In order to prepare for a failure, a pc or server is chosen to act as the designated standby server and the Virtualboot application is installed on it. It is important that the pc or server has adequate memory and be of the same architecture at the machine that it’s going to temporarily replace i.e. if the server is 64 bit then so must the designated standby server. Now it is not necessary for the pc or server act a purely a standby, it could be the receptionists computer which when required, acts as the standby server.

What happens if the server crashes?

In the case of a server hardware failure, VirtualBoot, which is running on the standby computer, is pointed to the latest image on the NAS and it is booted. After a few minutes the server is operational and the business can continue to operate as thought the failure had not occurred.

If must be remembered that the virtual server will be slower than the original server but this will only be for a temporary time whilst the original server is repaired or replaced. Also whilst the virtual server is operational, it continuous to use ShadowProtect to backup to the NAS so that all the current work is captured.


Once the failed server has been repaired or replaced, recovery can take place using the images on the NAS. Once all have been processed, the virtual server can take the final backup and shutdown. All that is then necessary to take place is for this final backup to be processed by the recovery process and the server booted.

Data Loss

The amount of data which was lost in the above scenario is equal to the amount of data which was changed from the time that the server crashed to when the last backup took place. The minimum backup interval that ShadowProtect can use is 15 minutes. So if this interval was being used then the maximum amount of data loss would have been 15 minutes.

Business continuity

There is more to Business continuity than just backup strategy albeit it is an important part. If you would like assistance to create a Business Continuity plan or set up the above strategy to look after your backup and disaster recovery implementation please contact Computer Troubleshooters – Parramatta on (02) 8208 3415.