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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? 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". 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. "Never run disk-intensive applications directly against
files stored on the thumb drive."
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. Related:
Article 10152 | Posted April 12, 2006 |
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Is there any software that will test a thumb drive for remaining life / failing cells / etc?
Posted by: doug at February 26, 2007 4:54 PM-----BEGIN PGP SIGNED MESSAGE-----
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Not that I'm aware of. You could try CHKDSK /R on it, perhaps.
Leo
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Posted by: Leo Notenboom at February 26, 2007 5:00 PMTjelzGXS2LfI0L3AeM8e1TM=
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I have a USB thumb drive problem. Just bought a new one 3 weeks ago. I cannot move files to it any longer, the message comes up as "the directory or file cannot be created." I can move the file into a subfolder already on the drive but cannot move it into the drive itself without putting into a subfolder. Also, I cannot rename a subfolder in the drive. I had the same problem on a previous USB drive, bought a new one and all was OK for about 3 weeks, then it happened to the new drive also.
Posted by: Tri Dinh at May 21, 2007 4:21 PMthanks, Tri
Yap...it can be quite headache with Thumb drive. I can see my files in the USB drive,but when I try to open or copy them out to another drive, it could not.
Posted by: Patrick at October 25, 2007 3:52 PMI could not even defrag it. any solution?
I would think that in normal operation users would be more apt to lose their data in a laundry cycle than write as many times as needed. Backing up these devices is sage advice, but there isn't a need to throw them out (unless it is with the wash!)
Posted by: Reg at March 4, 2008 1:21 PMHeck, Microsoft even encourages the use of USB Flash memory as extended RAM/pagefile in Vista.
http://www.microsoft.com/windows/products/windowsvista/features/details/readyboost.mspx
Like the previous poster Vista's ready boost system has always worried me from the point of view of wearing out the USB flash drive. I always believed that USB memory sticks had a limited read-write duty cycle and presumably using readyboost means that data is being written to and from the drive at a very high frequency?
We really need to get someone from the flash drive industry to comment on this as increasingly we seem to be heading for solid state disk drives like the optional one in the Mac Air. If these drives are comprised of the same flash memory as USB sticks then presumably they have a limited life span that may be much less than the equivalent hard disk.
Don't get me wrong I want solid state technology as it peeeves me that in the year 2008 we are still using storage that has to spin at 7500 rpm or faster and they are the cause of so much noise, heat and power consumption. Flash drives are better in every respect ... except perhaps one??
Posted by: Graham Sivill at March 4, 2008 2:20 PMTwice I have killed thumb drives when using them to move data from a MAC to a PC. MAC USB devices are not hot-swappable and if you forget to "eject" the device it can not only destroy data but render the device forever unusable. Neither the MAC or the PC now recognizes the existence of the drive(s).
Posted by: Tom Garcia at March 4, 2008 2:56 PM-----BEGIN PGP SIGNED MESSAGE-----
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Everyone uses ReadyBoost as some kind of counter example,
and it's not.
Regardless of the terminology used, ReadyBoost is NOT,
repeat NOT a paging file in the traditional sense. It's much
more like a dynamically tuned pre-load cache, where Windows
can *read* things from quickly as much as it needs to.
Readyboost does NOT *write* to fash ram excessively - it
only updates that pre-load cache on a kind of as-needed
basis.
I've heard of one person actually putting their real Windows
swapfile onto flash memory. It lasted about two days before
the flash drive died. And yes, died as in throw it away
dead.
I stand by my statement: flash memory wears out. It's
getting better, lifespans are increasing, technologies are
being developed to avoid wearing it out any sooner than it
has to, but the bottom line is that writing to flash memory
wears it out. The more you write, the shorter the lifespan,
as simple as that.
Leo
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Posted by: Leo A. Notenboom at March 5, 2008 8:57 AMk6ggrwYXHIzavGMTRgEOU9g=
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1. The person who could write to subdirectories but not the root - maybe your root directory is full; try (moving everything out of and then) deleting a directory. There's a finite number of entries allowed in the root in many filing systems.
2. Hard disc bits fail too! It would be interesting to hear some how-many-writes figures for them (and maybe other technologies - ISTR CDRWs aren't very high), to companre with the 10k-100k that seems to be being bandied about for flash.
Posted by: J. P. Gilliver at March 6, 2008 12:16 PMA quick search reveals that SLC flash has 100000 and MLC flash has 10000.
There is almost NO need to worry about wearing modern flash memory out.
If I format and rewrite the ENTIRE flash disk twice a day, it'll last for more than 13 years with a cheap (read, common) MLC USB flash disk.
In any case, USB flash disks ensure that the wear is even, not concentrated. So it's not 10,000 writes; it's much, much less dramatic.
Use your USB as much as you like; it will be obselete before it is ruined.
Posted by: blahbleh at April 12, 2008 12:03 AM