for a home pc is it worth doing a mirror raid set up, as i am just looking to back up all data as you can re install the applications again if worst comes to worst or do a ghost if advisable. Would i just be best to do a back up once in a while of the data stuff and copy data files on my external drive. Also doesnt the mirror raid slow things down a bit.
can anyone advise if this only slows things down when you are copying something or will this be slowing things down in general in the background.
The value of raid-1 for protecting data is that you can recover from a hard drive failure quickly.
It is for servers that can't afford any down time.
Recovery from a hard drive failure is just moments.
Fortunately hard drives do not fail often.
Mean time to failure is claimed to be on the order of 1,000,000 hours.(100 years)
Raid-1 does not protect you from other types of losses such as viruses,
software errors,raid controller failure, operator error, or fire...etc.
For that, you need EXTERNAL backup.
If you have external backup, and can afford some recovery time, then you don't need raid-1.
Doing RAID-1 can have its benefits, but also some drawbacks. Benefits include the possibility that reading files could be faster, such as with RAID-0, because you have a copy of the file on another drive. Why force it to read from one drive when two are available? And the obvious, you have a mirror image of your drive. So if your main drive fails, you can just swap with the mirror image and you're up and running in minutes.
The caviat is that having a mirror image could also be bad. RAID-1 is NOT for backing up your files on your bootable volume. Any viruses, trojans, or spyware you get will cary over to your mirror image. Any data that's lost due to that or an accidental delete will also be lost on the mirror. So, RAID-1 on your bootable volume is not for file storage.
If it's within your budget, have just one drive as your bootable disk, and then have backup drives in RAID-1 for redundancy. You will have three drives that way instead of two, but most viruses and whatnot should not effect the backup disk.
Another option is to RAID-0 your bootable volume for performance, and have a large, high-quality backup drive with a good warranty.
Also if you do end up going with RAID of any type, you should go for drives that were built for RAID. Those drives tend to be about 10% more expensive, but have the ability to recover from some RAID related failures and could save you money in the long run. They also usually have 5-year warranties and are generally built stronger.
Like mentioned above, RAID won't help you out in the case of a PSU failure. If the PSU dies, it could take out all drives and render your RAID a failure, mirrored or not. An external drive could save you from that kind of failure.
Use RAID1 and backup to an external drive on a regular basis. That way you can quickly recover from a hard disk failure (a rare occurrence in a system having a single disk) while having a backup should you lose the whole RAID.
RAID is not a backup solution, as others have mentioned. Any number of things can go wrong with the RAID volume, or you may simply want to restore a file that was deleted, corrupted or misplaced (virus, user error, etc), in either case no RAID level provides protection (as it will replicate the error across the mirror).
All RAID levels are essentially performance level tools, to be applied depending on what situation you need to avoid the most. RAID 1 provides higher recovery performance (i.e. likely can avoid downtime) and RAID 0 provides higher general performance. Other RAID levels are just dirivatives of these two principles.
For a home user I think an external backup drive will provide the needed level of protection, RAID 1 is most likely overkill as it is unlikely the extra 4 hours of re-installation and patching will have serious consequences. In the end you probably benefit from the fresh install of the OS without all the accumulated junk. My advice is to seperate your data from your OS using two different disks and use an external drive to do backups, it is the least likely scenario to have problems.
A (working) backup is worth more than any form of redundancy. Because it not only protects you against hard drive failure, but also against things like:
- filesystem corruption
- virus attacks (only if the backup is offline)
- accidental deletion of important files
Therefore, for a home user not interested in preventing down time but more interested in protecting against data-loss, you might consider two bare disks where one is an (offline) backup. Preferably in another machine, so you can protect against fire/electrical dangers as well. It is no more costy than a RAID1, does not degrade performance since most RAID1 don't give you any. It only requires you to maintain a backup of your files, to the backup disk. You'll be safer off and don't need any RAID drivers and specific setup.