Helping people with computers... one answer at a time.
While the technology continues to improve, the fact is that flash memory has a limited number of times it can be written to. It can, in fact, wear out.
I have a database application that I share between multiple computers. We keep the database itself on a USB thumb drive and simply move that drive to the other computers as needed. The database is never copied off the thumbdrive, we just update it in place. Seems very simple.
A friend of mine just told me that I was asking for trouble. He said something about thumbdrives "wearing out", and that sooner or later, probably sooner, the data on my thumbdrive would become corrupt.
Is that true? Do these USB drives actually wear out?
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Let me put it this way: I strongly recommend that you backup the contents of that drive - also sooner rather than later.
Flash memory, the type of memory used in USB thumb drives and other devices, is very, very cool. In fact I'm loading up a gigabyte SD-Ram card for my MP3 player as I type this. But there is a dark side that people don't talk about much.
Flash memory "wears out".
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Flash memory chips are called "flash" because in order to write to it, the memory is loaded, and then a signal is sent to the memory circuitry that says "remember this" - kind of like the flash on a camera. (In all honesty, I don't know if modern flash memory uses this exact technique, but it remains a fairly accurate metaphor for the process.)
Once the memory has been "flashed", power can be completely removed and the memory will retain whatever was written to it.
The "problem" is that memory can be flashed only so many times. I'm finding numbers between 10,000 and 100,000 times - though as with anything, I'm sure that is increasing over time as well. Regardless, there is a limit. When that limit is approached, some portion of the memory may not properly remember what was written to it, resulting in corruption. It may only take a single bit of information to be wrong, or to "wear out", for the entire contents of a flash memory chip to be lost.
Scary, huh?
Some flash memory chips, perhaps even most, now also include circuitry to avoid "bad bits". Meaning that if portion of the flash memory finally wears out and goes bad, the chip itself can compensate and look like everything is fine. But that only lasts so long ... it doesn't prevent failure, it only postpones it.
Now, in your case, you're using USB thumbdrive in perhaps the worst possible way for longevity. Database applications in particular are notorious for writing to the disk - a lot - as tables, fields, indexes and the like are updated. Even if you don't write to your database, the files may be updated with things like "last access" information and other administrivia that still results in the USB drive being written to.
With all that writing going on, suddenly 10,000 or 100,000 writes to the same location in the flash memory doesn't seem that far fetched. Remember, in the unluckiest case, it might only take one worn-out bit of information to render the entire contents unreadable.
The best use of USB thumb drives and other flash memory based devices is simply copy-to and copy-from. By that I mean copy the information to the thumbdrive to store it, copy it from the thumbdrive to a local hard disk to use it, and then copy it back to the thumb drive to store it. Never run disk-intensive applications directly against files stored on the thumb drive. If you copy to and from even 10 times a day, that's still close to three years of usage for the low end of the flash memory lifespan. (Yes, I know that's not exact. In fact, it's way more complex than that, factoring in things like the type of file system, FAT or NTFS, the efficiency of the device driver, and even the circuitry on the specific flash memory device - but it's a good order of magnitude.)
You may also note that your application speeds up when you copy your database to the hard disk for use. While reading flash memory is typically quite fast, writing is not.
And finally, if you really need external storage, a thumbdrive may simply be the wrong solution to your problem. There are plenty of external hard drives that could do the same job without the write limitations. Or perhaps a networked solution is the way to go.
Article C2618 - April 12, 2006 « »
Leo A. Notenboom has been playing with computers since he
was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed.
After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers
to common computer and technical questions. More about Leo.
July 25, 2011 6:37 PM
Is it okay to play mp3 files by directly double clicking on icons on the flash drive. Or should I copy them first to my hard drive and then play them. Is there any disadvantage associated if I play the mp3 files directly from the flash drive.
July 25, 2011 7:49 PM
@Lancaster
There should be no problem playing mp3 files directly from your flash drive. Writing to the flash memory is what wears it out not so much just reading from it. And playing music only reads the information once for each play,
September 28, 2011 4:04 PM
Would it help to re-format the USB stick ?
30-Sep-2011
February 22, 2012 8:09 AM
I have used USB drives daily for several years, moving data between 3 computers in different offices. Most recently I have been using 64GB Corsair Survivor GTR and Voyager GTR USB drives. I have had more than a half-dozen USB drive failures. The USB drives consistently die by 18 months of use despite obsessive attention to unplugging rituals. When they die, it is immediately evident when plugging the USB drive into the computer: the blue activity light blinks continuously on the USB drive and the computer recognizes a lettered drive but no content. This failure pattern has not changed with size drive / evolution over the last 5 years. Occasionally there is a warning of impending failure (continuous blue light blinking can be reversed after powering off computer), but more commonly, failure is abrupt. I think the millions of hours before failure quoted for USB drives refers to testing in which the USB drives are continuously plugged into the same host computer. I think the chance of failure is highest when plugging and unplugging: static, voltage transients, etc.
Would love to see data on number of real-life plugs / unplugs of a USB drive prior to failure. And even better: a module on the USB drive that interfaces with the computer but is separate from the memory - and can be replaced independently from the memory!
January 14, 2013 8:00 AM
I don't think the number of plug / unplug cycles is going to be that significant. In one USB 'pen' drive test I saw online, the techie managed to get total failure under 8 hours without ever unplugging the device (he assigned the windows swap file to it).
And I have seen USB drives with removeable memory - they are called 'card readers'. I've even seen one where you can plug in up to 4 seperate 32Gb 'camera' type memory cards to create one raid-style drive across them.