Failed Hard Drive resulting in the array being corrupted?

Hi All,

Just looking for some help on an issue we have just had with replacing a hard disk on our server. please see below:

We insetred the new replacment disk into the server under the impression it was compatible. (Only diffrence was that the manufactured by a diffrent company) By inserting the new disk and setting it to rebuild, it forced a reboot of the server and because the server saw the disk as not being the same size of the drives in the array it has now corrupted the array on the server. (Note: it was the same size as the other drives when purchased though when the RAID array on the server was setup originally  the drives were configured so it uses a certain disk size per hard drive)

As it stands now the server is now unbootable. It could be that because the drive isn't the same size as the other drives in the array, the array needs to be rebuilt from scratch, this way it can be configured to use the replacement drive size correctly?

Does any one no more information on why this would happen and also any help in what to do next? Also what have i done wrong? :-(

Many Thanks