USB Flash Drives for Backup/Long-Term Storage?

cyberdigm is curious about this issue: "I am writing two books and have just recently gone through the trauma of having my hard drive flake out (physical damage to several sectors). Fortunately, while the OS instance was trashed, the file system is still intact, so I have been able to recover my files.Given that, I am now much more aware of the needed to regularly back up my files. I'd be interested in any opinions about the suitability of USB flash drives to help me solve this problem. The idea would be to store copies of all my files on a USB drive and back them up every day. I like that USB drives are generally fairly cheap. My concern is the long-term wisdom of this approach. Are there (practical) rewrite limits for USB flash drives? Is there a chance that the data would degrade on the drive over time? Other alternatives I am considering include external/USB hard drives. Of course, an overarching concern is that I'd rather not spend a lot of money."

Comments

Practical Concerns

[Marxist Hacker 42]

Experiences in using flash memory for backups on PocketPC:

#1: Rewrite limits. Currently, flash memory has about a 1 million rewrite limit theoretically. In practice, though, I had a CompactFlash card (no real different technology from the USB drives other than interface to system) fail after about a year of daily backups.

#2: Time-to-destruction- I once left pictures of my honeymoon for nearly 6 months in my digital camera, also using flash memory. After 6 months, the files had a 50% corruption rate. So I wouldn't consider this a very long term storage solution- at least not without refresh.

Asside from those concerns, it's a very cool idea- especially if you kept the backup software on the key and increased your potential by using say, 7 keys (one for each day of the week) and kept the backups off site.

Re:Practical Concerns

[captnitro]

My dad loves floppy disks. He's one of those guys who's locked in a particular era of computing, probably around 1995, he loves WordPerfect and Lotus Notes, simple websites and lets the computer run overnight -- after closing all other programs -- for 1 meg downloads. (If you touch it, it might stop.)

He also won't, for the life of him, trust hard drives, zip disks, CD-Rs, dedicated network storagem or anything else to store his resume, which he updates and tweaks nightly. Not really in need of a job, being an international energy lawyer (i.e., oil man, and in *this* administration of all times), it's more of a hobby.

Luckily, there's something about the size and heft of the disk for him that makes it oh-so-magical, so I got him a DynaMO drive, which is a magneto-optical drive. I won't go into details (someone feel free to provide), but because of the way the media is written to the disk (not to mention the casing), they can take a beating, and much more than flash or other 'sensitive' media where scratches, low heat, or simply Murphy's Law can kill your data.

Pricey (~$200-250), but not considering you're writing books. Use some of your advance money and invest.

Re:Software RAID

[Hank Reardon]

That's all fine and good... Until you have multiple drives in the array fail. I used to think it was such a low possibility that it just wasn't worth worrying about.

I've lost both drives in a mirror set within 15 minutes of each other three times now.

Durability of USB Flash Drives

[shankar2k]

I have no idea how long the data will stay on a USB flash drive, or how many times you can write to one. I put my USB flash drive through the washer and dryer on accident. The drive contained my master's thesis in it. When I connected the drive to a computer, I discovered that not a single bit of data was corrupted. Doesn't that rock!

Failed USB Key

[musicon]

I've had a USB flash drive fail completely after about two months of every-day (not heavy) usage. First the drive wouldn't allow me to overwrite a file, then it stopped mounting, and then it stopped being recognized as a valid device - all in rapid succession over 5 minutes.

This was with one of the Sandisk Mini Cruzer 256MB drives. I replaced it with another Cruzer (newer model), and after another three months it's mostly reliable, however I've had it become "unplugged" on its own a few times recently.