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Thread ID: 122912	2012-01-20 03:40:00	Poor Man's RAID	John Calvert (16516)	Press F1

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1255247	2012-01-20 03:40:00	Hi All Like many of you I've acquired a few hard drives over the years. Also I have a lot of files that are not the crucial core ones I work with every day, but things like .iso copies of software CDs and so on that I'd like to be able to toss away the physical media and just read on a virtual drive. I wondered if I could set up some sort of RAID arrangement with an external multi-bay enclosure, but unfortunately, although they are available, my laptop's SATA controller can't handle it. This set me to thinking. I don't really need proper full-time RAID anyway - just some arrangement where there's a good measure of redundancy and a reduced chance of loss. Obviously a single copy of each important file on a different disk is the first line of defence. But since I don't use all my drives all the time, it's possible that if one of my frequently used external drives should fail, I might find that when I pull the old one that has the backup on it out of the cupboard after months of disuse, it may have expired too. So, without making more than two copies of everything, how can I minimize risk the risk? Turns out it's not all that hard. Let me outline the method I devised and I'd be interested in your comments or suggestions. I'm sure someone has thought of this before but I didn't have much luck googling it. First, let's set the terms: This isn't intended to replace your normal backup. It's for long-term archiving. It won't help you if your house burns down. More than 3 drives are required. They don't have to be the same size or type. As long as you can connect each one to your computer somehow. Failure of more than two at once is not catered for (hopefully pretty unlikely!) Rate your drives for reliability before you start. Obviously you won't include drives that you know or suspect are unreliable, but you should have some idea of how old and how much work they've done, and if, like me, you have no in-depth knowledge of the reliability of brands/models then age/use will have to do. This technique will only be of any use if you have a manageable number of large files (not thousands of tiny ones) as you're going to be moving them around manually. Zip them up into bigger files if you have to, or deal with them as entire folders. Method Make a diagram of the drives on paper, arranging them in a ring, and alternating the most with the least reliable. For instance, clockwise, drive 1 would be an excellent one, drive 2 a fair one, drive 3 an excellent one, drive 4 a fair one, and so on. The idea is to pair up old/new ones and not have two of the lesser ones adjacent to each other. If you have an odd number of drives, rate them "fair", "good" and "excellent" and arrange them so a "fair" one is always flanked on both sides by "good" or "excellent". Say we have seven drives. We'll number them 1 - 7. For this illustration the files will be identified by letters of the alphabet. File A would go on drives 1 and 2; B would go on drives 2 and 3; C on 3 and 4; D on 4 and 5; E on 5 and 6; F on 6 and 7; and G on 7 and 1, completing the circuit. Then keep going round and round, overlapping by one file each time. What this achieves is this: If non-adjacent drives (say, 1 and 3) fail, no data is lost - every file still exists on one of the remaining 5 drives. So you have a 50% chance of no loss. If adjacent drives fail (e.g. 1 and 2 or 7 and 1) then the loss will be only a percentage. The more drives, the lower the percentage. For instance, If two adjacent drives out of five fail the loss will be 20% of the files. Hopefully the odds are more in your favour by alternating old/new drives so that adjacent ones are less likely to fail simultaneously. Obviously there's a fair bit of work initially in moving your files around like this, but once it's set, new ones won't take long to add to two drives. But you have to keep track of which drive you last used, and your diagram of which is the next one for the second copy. The other thing is, you need to catalogue them all at regular intervals so you know what's lost if you have a failure. I was hoping Copernic (which I already use) could do it, but unfortunately it erases its catalogue for an external drive next time it does an index after the drive is detached. So I use Visual CD instead, which can catalogue external drives as well as CDs/DVDs and has a nice search feature so you can find your stuff. Once each drive is set up you can just "refresh" the catalogue with one action after you've saved each new file.	John Calvert (16516)
1255248	2012-01-20 03:57:00	1. Whats the brand/model of this laptop?? 2. Does it support RAID?? 3. What version of Windows (if you use Windows) is it? 5. If the SATA controller cant handle it, it may need the right drivers (if it supports RAID)	Speedy Gonzales (78)
1255249	2012-01-20 04:15:00	Unfortunately it doesn't. I did a bit of research when I had my eye on a double-enclosure with RAID capability. According to the specs, although I have an e-sata port, the controller will only recognize one of the two drives so I'd be wasting my money. I'm using XP Pro. No matter. I like my solution better actually. I would have had to either buy several of those or be constantly mounting different drives in it. Instead I got a dock that handles 2.5" or 3.5" drives (for the ones that don't already have their own enclosure).	John Calvert (16516)
1255250	2012-01-20 10:34:00	Why throw away the physical discs? They are another backup!	Agent_24 (57)
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