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Data Storage

USB Flash Drives for Backup/Long-Term Storage? 81

Posted by Cliff from the reliability-of-flash-media dept.
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."
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USB Flash Drives for Backup/Long-Term Storage? More

USB Flash Drives for Backup/Long-Term Storage?

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  • Practical Concerns (Score:5, Interesting)

    by Marxist Hacker 42 ( 638312 ) * <seebert42@gmail.com> on Wednesday November 10, 2004 @09:14PM (#10783181) Homepage Journal
    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.
    • I'm setting up a "quick and dirty" backup for a coworker@home. I did some looking and can pick up an external USB hard drive enclosure and a used hard drive for about 1/2 the cost of a 1GB USB key. Not very handy for taking offsite, but they just got zapped in a major way and having some form (any form!) of backup would have greatly helped.

      Also talked to them about an iPod - they have a business so they could have depreciated as a backup device :)

      • Yes - picking up a cheap used hard drive is definitely the best way to safeguard your important data backups.

        Good call.
      • Back in the late 70s and early 80s I used to work at a computer bureau. For those of you who are too young to remember, a bureau was where customers took their raw data to be encoded, processed and backed up.

        The only practical way to maintain integrity, given that data was stored offline (in fireproof safes) on mag tapes was to use a grandfather/father/son system of backups, with special tapes reserved for end-of-month or end-of-year processes.

        I know we've come a long way since the days of batch-processing,

      • "Also talked to them about an iPod - they have a business so they could have depreciated as a backup device :)"

        An iPod is a terrible backup device. It has even more points of failure than a regular hard drive in an enclosure. If the proprietary cable that connects it to the computer breaks, you are dead in the water until you acquire another one.

        Furthermore, a common solution to iPod troubleshooting techniques is to run the restore through the iPod Updater utility. This kills all data on it. The iPod sh

    • Re:Practical Concerns (Score:4, Interesting)

      by captnitro ( 160231 ) on Wednesday November 10, 2004 @09:38PM (#10783337)
      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 [dynamoo.com] 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:Practical Concerns (Score:5, Informative)

        by name773 ( 696972 ) on Wednesday November 10, 2004 @10:02PM (#10783534)
        there are two sides to a magneto optical disk: a floppy-like side and a cdrom-like side. a laser heats the cdrom-like side until it hits a temp. where the magnetic portion directly below that hot point can be changed. a magnetic head then changes the polarity of that hot spot on the magnetic side. the disk is read from the optical side, and the dot on the optical side reads differently depending on the polarity of the dot directly oposite it on the magnetic side of the disk. this gives you over 1e6 rewrites, and the disk won't demagnetize under a certain (high) temperature. also, the shelf life is 50-100 years, in part due to the plastic (3.5" floppy like) casing mentioned by the parent. the disadvantage being that these drives are slow and expensive... slow because the drive checks what it just wrote and corrects the write if it's faulty (i think on a per dot basis). the upside is reliability.
        magneto optical discs get anywhere from 128mb to 5.2gb that i've seen, and they come in three varieties: minidisc, which is primarily for audio, but a few data ones are being sold, the old version holds ~1/5 of a cd, so ~130mb, the newer version (uses multiple layers) holds 1gb, and i don't know if they have a data version or not. 3.5" mo discs come in 128mb-1.3gb that i've seen. slightly older drives accept 640mb discs while the new ones take 1.3gb discs. this value may have increased since i last looked for a mo drive. 5.25" mo discs come in sizes up to 5.2gb so far as i've seen; this value might be bigger now.
      • Smart dad.

        Here's how I do it. Certain critical small configuration files always get backed up to floppy. They also get backed up to multiple drives on multiple machines along with all of the larger files. I don't trust burners or flash except for sneaker net ops.


      • He also won't, for the life of him, trust hard drives, zip disks, CD-Rs, dedica...

        two words: print it

        I don't trust any storage media 100%. If something is really important to me, I print a hard copy. It's not that I don't burn backups to disk, or even ftp stuff to other machines, (I do) but nothing beats the trust factor I have for paper and ink.

        My filing cabinet hasn't had a single crash or virus in all the years I've owned it...
    • Do you live close to a nuclear reactor or something? Maybe under some high-tension power lines?

      I believe your story, I don't think flash drives are suitable for long term storage...

      However... to add my own $0.02... about 18 months ago I lost a 64MB USB key... couldn't find it for the life of me... it had several documents that I really missed and was mad about losing...

      I decided to sell my car... found it jammed against the power-seat rail... the external case was cracked from it being ground against th

  • Software RAID (Score:2, Informative)

    by Pan T. Hose ( 707794 )
    Software RAID on a bunch of different hard drives (preferably SCSI, but you can also use IDE/ATAPI/UDMA/USB) and automatic off-site (e.g. a remote ftp or scp) backup cron job should do the job.

    • Re:Software RAID (Score:3, Interesting)

      by Hank Reardon ( 534417 )

      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.

      • Re:Software RAID (Score:1, Insightful)

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

        Dude, get a fan. That is normally the problem. Also, dont forget to send the drives back to the manufacturer... the will let you know what happened. ( normally a 3 year warranty). As a bonus you will get new drives.

        btw- When did you get out of the steel buisness?
        -- john galt

        • Dude, get a fan. That is normally the problem. Also, dont forget to send the drives back to the manufacturer... the will let you know what happened. ( normally a 3 year warranty). As a bonus you will get new drives.

          The problem wasn't heat, it was flaky Maxtor drives from the same lot. Two of the replacements I got from Maxtor also failed in the same manner.

          btw- When did you get out of the steel buisness?
          -- john galt

          Well, you know... I kinda got down in the dumps for a while, with a friend screwin

      • Re:Software RAID (Score:3, Informative)

        by DA-MAN ( 17442 )
        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.

        Uhm, I think the parent poster did in fact cover that. Let me paste it back for you:

        Software RAID on a bunch of different hard drives (preferably SCSI, but you can also use IDE/ATAPI/UDMA/USB) and automatic off-site (e.g. a remote ftp or scp) backup cron job should do the job.

        See bold text if you still don't get it . . .
      • "I've lost both drives in a mirror set within 15 minutes of each other three times now."

        Are you sure it's not a flaky power supply killing them off? It's an often neglected cause of hard drive failures.

        • Are you sure it's not a flaky power supply killing them off?

          Yep, I'm sure. I explained it completely in another response in this thread, but I got bit by the fact that 1) the drives were from Maxtor; and 2) they were all from the same manufacturing lot.

      • Were these drives that failed in your array of the same manufacturer, model and batch? Like using different vendors' hardware for Internet routing to prevent vulnerabilities from killing off your whole network, you should use drives from different manufacturers or batches from the same manufacturer in your RAID array to prevent the same failure occurring in both drives at the same time.

        • Yep, and that's what nailed me at that particular point in time. I had purchased a box of 24 drives from the store to use, not even thinking about batch-related failures.

          Plus, come to find out, Maxtor seems to be a little looser on their "good" qualifications for the platters, so that was another negative.

          It's one of those "live and learn" situations. I do try to keep with the same manufacturer so that the performance specs are the same, but I carefully check the lot numbers before making purchases like t

    • Screw SHITY raid go for hardware. Buy an arco duplidisc and two ide disks. Then make regular backups of your valuable data and send them of site.

  • relatively cheap or reliable. (Score:3, Insightful)

    by emptybody ( 12341 ) on Wednesday November 10, 2004 @09:16PM (#10783192) Homepage Journal
    which do you prefer?

    why do people not realize that costs for the physical item are only part of a price tag?

  • NAND based...... :-( (Score:3, Informative)

    by oroshana ( 588230 ) on Wednesday November 10, 2004 @09:20PM (#10783210) Journal
    Almost all flash drives are made using cheaper & smaller NAND flash (rather then NOR flash which requires more transistors per bit of storage). This type of flash wears out much more easily then NOR flash.

    If you decide to use these flash drives as a backup medium, you should definitely use some sort of encoding that allows for bit-corrections. Possibly some sort of Forward Error Correction. Or use a RAID parity/striping method.

  • Couple of easier, low-tech solutions (Score:4, Insightful)

    by Txiasaeia ( 581598 ) on Wednesday November 10, 2004 @09:32PM (#10783284)
    You're talking about text, right? First of all, if you're writing a book, you should probably get hardcopies of various drafts. Take 'em to office depot, pay $20 and get it all printed off for you.

    Second, since we *are* just talking about text, it might be worth your while to use email. I've got a community network email account that I do this with - email them important info, they store up to 15 megs worth of data, where it will pretty much sit forever.

    Third, little more expensive: last I checked, a 512MB USB disk drive costs about $70 CAD; you can buy a brand new low GB HD for about that much. Just run two HDs on your system, sync the data every night, and there you go. HDs don't tend to flake out as often as you think, and this way if one goes, you've still got an onsite copy. Then just buy another $70 HD and keep going.

    • Of course, if you email stuff to your own Gmail account they will store 1 GB, and you can search it too. Duh.

    • email them important info, they store up to 15 megs worth of data, where it will pretty much sit forever.

      Have you tested this version of foreverness?

      • Don't try this on Hotmail.
        Those fuckers will destroy your entire inbox faster than you can say 'a 32 day vacation touring Eastern Europe.'

        Not that I actually lost anything important, mind you ... but it still sucked.
        • while microsoft bashing is always great here, lets put it in perspective. people who have paid accounts like myself dont have these problems. I also have 2gb of storage and a rather large attachment limit. Now you may say, look google has thes features and they're FREE, why dont you switch? I say this,

          1) I've had my hotmail account for many years, and since its my primary accoutn I couldnt switch if I wanted to, I need it - too many people have that address. The only downside I have with hotmail is they do
    • I would passionately dissuade anyone from choosing a RAID solution. I used to have two HDDs in my office PC (completely different make, model) and they both crapped out at the same exact moment. It might have been a power fluctuation, or one burning out the other, I don't know...

      However I do know that most PC power supplies are despicable as of late, with a suicide rate far exceeding that of HDDs (except for certain IBM models :)). And if your power supply goes, you have a pretty good chance that your data

      • just because you're running some cheapo raid setup with no redundancy doesn't mean that proper, hardware independant raid isn't a good idea. it's there to provide AVAILABILITY, not backup though: delete a file off RAID and it's gone: this is why you should have backup as well - e.g. to tape kept offsite.
    • What about the combination of choice #2 and #3? The advantage of email is that you can have access to it at any computer that is connected to the Internet. The advantage of drive-based, is that you can have access to it at any (non-Internet connected) computer that you pop the key-drive into.

      So I guess that would be an auto-script that copies files to the key drive every time it's plugged in, and also mails a copy of those files to Gmail. So then your "backup activity" would consist of plugging in your key
    • I run a company (312) that has put out an online solution, LeanOnMe. It is less expensive, is safe and secure, and handles text files in a breeze. It's automatic and easy to use as well. Platform independent too. Backup to multiple computers online, and you are even more secure. The second hard drive option is effective too, assuming your computer is in a safe place. Otherwise, distributed solutions work better.

  • GmailFS (Score:3, Informative)

    by alatesystems ( 51331 ) <chris AT chrisbenard DOT net> on Wednesday November 10, 2004 @09:34PM (#10783301) Homepage Journal
    Back up your data off site on GmailFS.

    Win32 Version [viksoe.dk]

    *nix version [jones.name]
    • Gmail backup is a good idea. But why bother with GmailFS? It sounds like a cool hack but it says at least twice in the documentation that Google could shut it out at any time.

      Just send to your gmail address a text attachment containing each night's changes to the work and there it is - a running back up of your book, accessible from anywhere.

      You might also look into encrypting it. Isn't Google going to open the email up to its search engine after some period of time?

      • Isn't Google going to open the email up to its search engine after some period of time?

        What!? They wouldn't do that. Not because they're "not evil" or anything, but because 1) random people's e-mails will dilute search quality and 2) they will get sued out the window if they try to make these e-mails public, regardless of how you can interpret the user agreement.
        • It does sound unlikely to me too but a member of the tinfoil hat squad in a UUG nearby posted very vehemently and almost convincingly (i'm looking for the message now) that once messages had been stored for some period of time they would be accessible from the outside. I was kinda hoping that my bringing it up would prompt someone more clueful to chime in and clear it up for us all.

        • In other words, some people have some concerns [gmail-is-too-creepy.com] about gmail.

  • Use multiple approaches (Score:5, Insightful)

    by GCP ( 122438 ) on Wednesday November 10, 2004 @09:42PM (#10783362)
    The more media types and locations, the better, but concentrate on the small percentage of your data that you couldn't recover by just buying or downloading another copy. Concentrate on your own personal data, and the job will be much easier to manage.

    The USB drive will be fine as one approach--use it daily--but don't leave it at that. It's a convenient medium, but you want it to be able to fail without hurting you much. If you combine it with other media, you can enjoy the convenience without exposing yourself to whatever risks there may be.

    Then get yourself Web hosting from some reasonably good quality host and FTP your files to your own website. If you're not very technical, the Web host can tell you how. You don't need to learn how to build a website to FTP files. The more important the data is, and the harder to recreate, the more you need to have it on the website. If you can just get it up there, they will do your backup for you. This assumes that you don't have tens of gigabytes of personal data, which could be a mistaken assumption if you are talking about photography, for example, instead of writing.

    From time to time, burn a CD-R of your files (or multiple DVDs if you have gigabytes of important personal stuff), make multiple copies, and stash them in different locations: with your parents, in a self-storage locker, or whatever. That's too much bother to do very often (if you include the offsite stash), but it's a good thing to do occasionally. Just to be sure, check and see if the CDs/DVDs you burn can be read in your parent's, friends, or kids' computers.

    • If the questioner really only wants to save his books, there is cheaper way than getting his own webspace--a Gmail account. Email it to your gmail account and, if your hard drive fails, it is still there. This won't work for large files because the attachment size limit, but a book should be less than 10MB.

  • Multiple Redundancy (Score:5, Insightful)

    by D.A. Zollinger ( 549301 ) on Wednesday November 10, 2004 @09:44PM (#10783389) Homepage Journal
    Any kind of backup solution is preferable to a single point of failure. USB Keys may not be the best solution out there, but it is certainly better than having only one copy on your hard drive. I would look at more than just USB keys, there are certainly plenty of options for copying and making backups of your data, from CD-Rs, and iPods, to zip disks, and external USB/Firewire hard drives.

    While a USB key is certainly portable and convenient, it may also create another problem - easy theft of your work. How easy is it to lose a USB key, or have it stolen. And what happens if the finder claims your work as their own? If you did use a USB key, I would definately not keep it with you, but store it in a safe and secure location.

    In that vein of thought, since you are working on a book, do you keep hard copy backups? I know it would be a pain to OCR all those pages back in if you lost everything, but it would be better than starting from scratch. If kept in a fire retardant safe, they would fare much better than digital media would.
    • Any kind of backup solution is preferable to a single point of failure.

      This is a very good point, but I don't think the parent post takes it far enough.

      If your livelihood depends on your data, back it up in multiple locations. A USB key is convenient for moving your data around, but it's not designed for backup. First, backup your working directory daily to one or two backup directories on the same drive; this is convenient if you accidently munge your working directory.

      Second, backup your working dire

  • A bit pricier, but you get what you pay for:
    External harddrives [maxtor.com]
    (sorry if the link is bogus)
  • USB flash drives are pretty small... less than 512 mb max, generally 128 mb normally. I'm assuming, then, that you need to store about 128 MB of stuff. I'll also assume from your statement about external drives that you've got a laptop with very little room inside.

    The best option for you would be network backup. Seriously. Either pay a little for a little space on a remote server somewhere, or squeeze a folder out of your friendly publisher network technician / techy friend / college kid / local bum.
    • Check again. 128MB was the norm 6 months ago, but now 1GB drives are available for $100. The industry is moving *very quickly* it seems. I bought a 1GB "Intelligent Stick" a month ago for ~$80, and two weeks later observed another brand's 1GB drive going for ~$60 after rebate. You can now get 4GB drives.
  • I've used a 256 meg flash drive to back up a website or two and some other files intermittently over the last year, maybe a little more. It's handy because I can carry the backup offsite immediately, so in the instance of absolute mission-critical data even the remote chance of some sort of physical catastrophe (fire, natural disaster) I'm covered. The newest generation of USB flash drives are very fast, handy, and cheap.

    My only worry has been actually losing the drive itself. Then again, I'm doing interm

  • Gmail (Score:2)

    by bhima ( 46039 )
    Sure Flash drives will work but you really need redundancy and it sounds like Gmail might suit your needs. E-mail me if you need an invite.
  • (or any other webmail with sufficient space)
    Email yourself a daily backup.
    Reasonably secure, readily accessible storage, plus fodder for a future book: "How I wrote the Great American Novel - Stages and iterations."

  • RAID 5 (Score:5, Funny)

    by xornor ( 165117 ) on Wednesday November 10, 2004 @10:45PM (#10783817)
    My computer has 6 usb ports, get 6 usb flash drives and RAID 5 them. If one dies replace it ;)
    • Seriously, is it possible to do this will Linux software raid? Have several USB hard disks plugged in in RAID 5; if one fails, just replace it and watch the software sort everything out...
      • Yep , sure is. the "md" driver ('man mdadm' will answer all your questions) doesn't care what kind of block device you use. I tried it with raid 0, 1 and 5 using a small HD partition, a usb key and a floppy as block devices.

        It worked as you'd expect, the array was as slow as the floppy, the floppy never stopped moving, but it did work.

        md is fun when you're bored. I also set up a 4 device RAID 5 on a single drive with 4 partitions to win a bet with a friend who said "you can't do raid 5 on one drive".
      • Here's a guy [8k.com] who built a software RAID using USB floppy drives on OSX.

  • gmail (Score:1, Redundant)

    by RalfM ( 10406 )

    1 gig of space, just send yourself an email with the latest version every day when you're done. You can clean up after yourself if you do run out of space.

    (email me at ralf at muhlberger.com if you need/want an invite)
  • For almost free (at least a fair amount cheaper than USB keychains) loyou have alot of (probably) better options:

    1) Web storage (encrypted to your heart's content)
    2) Floppies/cds (yes, they arent great for long term, but if you make semi-frequient backups, that should be no problem.)
    3) Hard copies. Just take the files down to kinkos/office depot/whatever and print the entire work off. (re-entry might be hard, but non-recoverable data corruption would be harder, also sometimes editing by hand is a nice alte
  • If cost is a real deciding factor, then (depending on the size of the files you need to backup) thumbdrives can be expensive. Reliability is a problem too as these little thumbdrives can get damaged/lost or stolen quite easily, however the chance that a thumb drive will fail at the same time your system fails will be fairly low.
    The Email option is a good standby and can be relatively cheap (some one on this thread offered you a GMAIL invite, there's 1GB of online storage for nothing), also Yahoo offers a 2
  • Seriously, CD-Rs are probably cheaper, and almost certainly more reliable. If you multi-session they'll be even cheaper.

  • My opinion based on work in flash storage industry (Score:4, Informative)

    by baywulf ( 214371 ) on Thursday November 11, 2004 @01:37AM (#10784881)
    These is my comments based on working in flash storage industry. There is an endurance limit to flash drives. The nand flash media are rated at about 100K erase/write cycles but in reality it can do more. There is additionally ECC correction to extend the life and preemptively recover with a sector goes bad. Once all the spare sectors go bad drive would likely prevent any further changes but still be readable. To give the most even wear and entend life, use a backup strategy where you erase all files and then rewrite or add incremently. Random write are the worse. Lastly flash failure decreases greatly with temperature so store at stable temperature.

  • What happens? (Score:4, Informative)

    by dasunt ( 249686 ) on Thursday November 11, 2004 @02:15AM (#10785073)

    When your house burns down, or floods, and your drives are underwater, including the backup drives?

    Here is how I would probably do this.

    First, check out RCS. You have one file, you want to keep a record of revisions.

    Second, depending on how much I'd want to spend, I'd either back up to CDR once a week (keeping the old backup "off-site", say, on in my vehicle parked on the street, at work, etc) or else buy an online storage space for a few dollars a month.

    A quick google search shows 50 MB for $3/month [ibackup.com], which is a lot of plain text. If you are using some funky word processor format and/or images, half a gig is available for $10/month. It even supports rsync!

  • 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!

  • My (expensive) USB flash stick died a few weeks ago, after two years of usage. I could still read it, but it refused to be written. Gladly, my vendor gave me a new USB stick for free, but this is definetly not the media I want to store my important files on.

    My backup is an external firewire case with a large ATA harddisk, combined with a script that writes all modifications in the main RAID-1 filesystem to the backup harddisk. Tape drives are too expensive, and tapes wear out rapidly. Burning complete back


  • One of the plan9 file servers uses block hashing for it's file store. Thus if you save the same file twice it doesn't use any extra disk space (modulo housekeeping meta data)

    thus you could backup 100 windows machines and you would consume the sum of their overlapping data, repeated data not repeatedly stored

    in this way plan9's full daily snapshot backup system consumes something approaching the minimum disk space required, one can step through one's file system a day at a time

    this would be a useful way t

  • Failed USB Key (Score:2, Interesting)

    by musicon ( 724240 ) *
    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.

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