Saturday, June 9, 2012

Make a software RAID bootable?

Is it possible to create a bootable software RAID0, RAID 5, or span with a Windows installation?
The answer is "NO".
One cannot start an OS from a software RAID0, RAID 5, or JBOD. A hardware controller is needed to do this.
It is not possible to boot off the software RAID for the RAID is not accessible until the operating system is done loading, and the operating system itself is on the RAID. The only option is to boot off a software RAID 1, and even that is not that simple. To boot from a "shadow" disk of a software RAID1, you probably need to copy the master boot record first.

Tuesday, January 24, 2012

One of the main data recovery policies is to check the restored files

When recovering data, just a few people would make sure that the data has been restored correctly although such a check is recommended in most all data recovery tutorials (e.g. in the data recovery guide).

Such a neglect may lead to the following scenario:
  1. you retrieve files and documents and the folder tree seems reasonably correct,
  2. the disk is formatted or original disk data is lost some other way,
  3. you find out that the retrieved data is not recovered properly.
It is obvious you should restore data once again. However, the original data is no longer available. So the conclusion is that you should check the retrieved data first and only then start to write data on the disk from which you have extracted data.

It is interesting that the same approach should be used in many other situations. For example, you bought a NAS device and the documentation says that it has an UPS and therefore can withstand power failure. But you should not just believe this but test - before placing data on the NAS, turn off the power and  see how your NAS feels in case of a power failure.