Hey Guys,
Been meaning to chip in here, but been flat out all day.
So firstly...
Do you think RAID1 is good enough to stop doing backups? The thing that worries me is environmental - both disks are subject to the same environment, running off the same power supply and motherboard, however I guess the chances of BOTH drives failing at the same time would be pretty low.
Basically, the answer is No. Although it is very unlikely that both drives will fail, it is feasibly possible; you'd be amazed at what I've seen, including but not limited to; a fault y drive interface toasting multiple drives, i've seen drives run over by industrial equipment, and you would be amazed at the damage that a bottle of coke can do.
However the main issue with a single Raid 1 disk is the "Human factor". Although the advantage of Raid 1 is that Data is written to both places simultaneously, the disadvantage is that data is erased/re-written in both places simultaneously too !!! I myself have written over backups, confident that I have the correct file / version.
Oops.
While we're on the issue of RAID, On a project that I was tech-consulting on earlier this year, We had 3 drives fail (of a 12 drive / 12TB array) in the space of six hours. Turned out the entire shipment had been dropped !!! Thankfully, we had a backup.
DVD's are a good option, however remember that DVD's can be quite fragile. A single scratch in the lead in, can mean lots of expensive Data recovery. Oh, and there is a virus that adapted to attack the organic layer that data is stored on. Pretty rare, but I have seen a few examples.
One of my clients has a strategy that works very well, for each new project they purchase 3 new hard drives, they store multiple versions / snapshots using Time Machine, so basically they can revert to any version of a file at any time. This is done and copied to all three drives. When the client leaves, (and has paid), they take 1 drive. When the client reports that they have stored the drive safely, the second drive ships, if there is some issue with the first drive, another copy is made, before sending it. Finally the studio holds the final drive for at least 12 months, and a final layer of safety.
Using the above method, there are always at least 2 copies of the Data accounted for at all times, with 1 in transit.
If only 2 copies existed, then if someone loses a drive, crashes the car etc, and the other drive fails, you have a problem.
I had a client, who was a photographer, he dropped the only copy of a hugely expensive photo shoot, involving a internationally known model, and a privately charted yacht, into a creek. The data was recovered @ phenomenal cost, but still less than re-doing the shoot, and the loss of his reputation.
As an aside, I also use an Application called Super Duper to make a bootable, working copy of my system disk. That way, if I lose a boot drive, I can still continue working, without having to spend the 2 or so days it usually takes me to rebuild and reauthorise my system.
Two final thoughts I will leave you with:
1) Remember that drive manufactures EXPECT their drives to fail, they have an "acceptable" failure rate. Please also remember, that what may be an acceptable failure rate for 1000 drives, becomes less acceptable if you are one of the inevitable statistics.
2) Think of the real cost of losing data, if you are prepared, it may be nothing, if you are unprepared but lucky, it may be the lost of some money and/or time, if you are unprepared and unlucky, not only could you get sued, but your entire reputation could be destroyed, potentially taking your business with it.
Media is cheap, your career isn't.
Posted: Mon May 26, 2008 11:45 am