External firewire 800 disk: Raid or non Raid?

I know nothing about RAID setups so why am I answering you ?

Well MartinR has written a bit about them in the past and some of it may be useful to you. Check out these threads for Martin's replies:-

http://discussions.apple.com/thread.jspa?messageID=7485130&#7485130

http://discussions.apple.com/thread.jspa?messageID=7637057&#7637057

http://discussions.apple.com/thread.jspa?messageID=7426811&#7426811

I am deliberately answering the question from your other post here so as not to put off replies to that post.

Speaking generally, the quality of any manufacturer is only as good as the device you have.

Take LaCie....... some people swear by them and others swear at them depending on the person's experience.

So far all my friends and myself have had nothing but excellent service (from LaCie), whilst others on these forums have occasionally slated them after having a number fail.

If people are worried about devices failing they shouldn't buy Macs according to a distant nephew of mine. He has his own IT company and keeps warning his parents (who use MacBook Pros) not to buy Macs, or if they do, get the longest warranty they can find. (They have had a number fail but staunchly continue buying them).

In his extensive experience with both Macs and Windows he states that Macs have a superior operating system but inferior, less reliable hardware.

So reading good reviews is no guarantee that you will be able to replicate the experience.

Hi,
You can read my other notes on RAID that Ian so kindly referenced above.

With an iMac, FW800 and 7200 rpm drives you have plenty of bandwidth for video editing with FCE, regardless of whether you're editing DV, HDV or AVCHD (note: with HDV and AVCHD you are actually editing Apple Intermediate Codec). So you're not going to see any benefit of using RAID for speed purposes.

I'd submit that your first order of business beyond online scratch disk space should be adequate offline backup. RAID does not give you that. If you're going to invest, I'd suggest completely separate drives for your scratch disk and backup. By that I mean physically separate drives in their own cases. Your scratch drive of course needs to be online, however your backup drive should truly be offline (disconnected, powered off) except when you are making a backup. Otherwise you don't have a truly safe backup.

TimeMachine is a wonderful innovation and very helpful for most people. However, it's not a substitute for offline backup. And, anyway, you should turn TimeMachine OFF while you are capturing, editing, rendering or exporting with FCE - in other words, turn it off whenever you're using FCE.

Hi again,
Yes, that's the idea. I'm suggesting 2 separate drives, whether they are 500GB, 750GB or 1TB is up to you. When you back up, FW800 will enable transfer of about 2GB per minute, you can use that as a guide for how much time a total backup would take. Be sure to format them as Mac OS Extended before you start using them ... many drives come from the factory formatted as FAT32.

OK, so I've had dinner and some wine ... let me restate some thoughts about backup ...

RAID mirroring is an effective way to protect yourself against a certain kind of fault ... that is, the loss of one of the two drives in the mirrored array. I do not consider that to be real backup, but it is a protection against disk failure. And there is definitely convenience in having your primary drive duplicated on the second drive in the array, in background, all the time, without any intervention on your part. The risk, however, is that most faults originate from user actions or software faults, not hard drive failure; and in a mirrored array, if you inadvertently delete a critical file, well, it's gone from both drives; same if the disk catalog becomes corrupted, in which case you lose everything on both drives. (Note: this can and does happen. Imagine my shock when iMovie was reconnecting to media and in the process got into a loop that eventually took down the disk catalog on my primary data drive ... ooops .... good I had an offline backup ... and hooray for ProSoft Data Rescue II !!)

That's where offline backup becomes important. With truly offline backup you minimize the risk of losing a file because of some user or software fault. That is because the drive is not online except when you are making your backup. The benefit is a significantly higher level of protection. The cost is the long time it can take to backup a drive that contains a lot of data. 500 GB of data, backed up over FW800, can take on the order of 4 hours to back up. That's quite a cost in time and the risk that something untoward might happen during those 4 hours.

The point is, using multiple levels & types of backup is a very good idea.