Reliability of USB-based filesystems? Lack thereof?

[Madison Kelly]

Christopher Browne wrote:
> I have been running into a problem lately which I thought I'd "toss
> over the wall" to see if others have experienced similar...
> 
> I have been having *terrible* troubles trying to copy files of any
> material size (e.g. - such as videos and such) onto USB-based devices,
> notably USB memory sticks and onto SD cards mounted via USB.
> 
> I copy files over, and there are two tendancies:
> 
> 1.  Frequently, I run out of disk space on the device, even though
> there's certainly plenty of room left.
> 
> 2.  After completing copying, I unmount the filesystem (which takes a
> while, due to flushing out updates), and when I remount, the
> filesystem tends to be pretty corrupt, with wacky directory entries
> containing control characters.
> 
> I'm not at all sure that this is a USB-relevant issue; what I am
> getting mighty suspicious of is that perhaps I'm blowing up the VFAT
> filesystem (fyi, I keep having to rebuild the filesystems when I
> attempt a retry).
> 
> All seems to be OK if I keep to moderate file sizes (e.g. - a few MB
> in size); everything seems to go bad when file size grows to 100's of
> megabytes.  That's not formal "troubleshooting info;" that's more like
> an anecdote.
> 
> What seems rather interesting is that I observe this in a
> cross-platform fashion; I see this phenomenon both on Linux and on
> MacOS.
> 
> A quick google finds the following (reported on Darwin, I'm not sure
> if this is with "Hackintosh" or with "just Darwin"; don't think that's
> too relevant...)
> http://forum.insanelymac.com/index.php?s=fd9e8e56f8887e542acf2e01e7ea6917&showtopic=57523&st=0&p=410781&#entry410781
> 
> It is suggested that the problem might be insufficient power to the
> USB devices; that seems implausible when I'm mounting them on a
> desktop box where there should surely be plenty of power.
> 
> I have been seeing this phenomenon for a while, on a variety of hardware.

I've seen issues like this on cheaper USB-IDE chips where small copies 
are fine but big copies die. I think it's a power issue with those 
chips... Though you say you're having problems across different bits of 
hardware...

Personally, I always stick to just a few brands I trust (Vantec for HDD 
carriers and Kingston for keychains) and I've had great luck in Linux 
with multiple host controllers since then. Cheaper hardware though has 
caused me no end of trouble.

Madi.
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