ext3 / ext4 on USB flash drive?

[Theodore Ts'o]

On Fri, Aug 30, 2013 at 10:41:30AM +0100, Mark Ballard wrote:
> That said, the user forums are full of lost souls, despairing for want
> of an answer to the simple question of whether they could well or
> should not format their USB in ext3/4. Are you implying that it cannot
> be known unless the manuf gives you the specs and if this is the case
> and you've bought a bargain bucket flash drive (and assuming that
> without a decent flash h/w controller it is true that ext3/4 will
> thrash your drive) then you should stick to ext2? What then are the
> features a USB flash spec you should look for as the minimum required
> before installing ext4?

The cheapest crap is going to be "unsafe at any speed".  It might be
OK if you are using it for the occasional transfer of files from one
computer to another, but if you are going to be doing lots of updates,
your data is going to be at risk no matter what file system you use.

Some filesystems are more performant than others, so keep in mind that
a simple way to double the lifetime of some cheap crap is to slow down
the write speed by a factor of two.  :-)

So I wouldn't so much focus on whether some storage device is "good
enough for ext3/4", but rather, "is it good enough given the value of
the data of the data I'm storing on it, and the read/write patterns
I'm going to be subjecting the drive to"?

Cheers,

						- Ted