What file differences are there between mirrored system disks?

[sectshun8]

Here at work, for a few of our main systems running, we have mirrored "backups" if you will that we can boot to if for whatever reason the main boot disk gets messed up. We have actual backups as well, not really trying to say we use disk mirroring as a back, 'cuz that'd be retarded. Just added redundancy. So being that when you mirror to a second disk, you are in effect, making an exact copy of your current disk... what then are the file differences between the two? And if those file differneces did not exist, what could happen? Someone asked me this question and I wasn't quite sure how to answer it

This is all done on UNIX systems btw, if that matters.

[BipolarBill]

There should be no file differences between the two. All files are written to both drives simultaneously.

Keep in mind that the drives require connection to the RAID adapter to work.

[Nude_Lewd_Man]

RAID 1 is where you have "mirrored disks" and each disk is exactly the same size, meaning you lose out on overall capacity but have the ability to have a disk fail (or be removed as a basic kid of backup strategy) and replaced and rebuild the mirror.

RAID 0 means that all drive space is added together, but if any disk fails, the lot is gone - as it would be with a single disk.

RAID 5 is like a combination of the two, where you get more space (but not the overall total) with the ability to have a disk failure, as data is written across all three (or more) disks. It does not however allow for a disk to be removed from the array as a basic level backup - as RAID 1 can...

RAID 10 is actually a combo of RAID 1 + 0 (hence 10) and spreads data over (normally) 4 disks and gives the speed and space advantages from RAID 0 while having the redundancy that you get from RAID 1...