DragonFlyBSD

:It doesn't happen with any other OS (tried Debian, MacOSX and Windows XP)
:and there is no problem in DragonFly with the very same formatted to UFS
:either.
:
:--
:Hasso Tepper

I'm guessing it is a function of msdosfs, which doesn't try to
    aggregate clusterable writes.  Linux's block devices work differently,
    it's easier for linux to cluster writes.  Not really on my list,
    non-native filesystems aren't really designed with performance
    in mind.

-Matt
                    Matthew Dillon 
                    <dillon@backplane.com>

50MB in 4 minutes isn't really "a performance problem" IMHO, but a serious
usability problem ;). And I doubt that the lack of clustering is the one
to blame here (at least not alone). And as I said - it isn't the problem
with every USB mass storage media, with other stuff I have access to show
reasonable performance with msdosfs.

I've noticed that writes to msdosfs always used 4kb blocks. That's probably a clustering problem then.

cheers
simon

Does the behaviour change if you use standard 512-byte blocks? People
seem to think that USB pen/flash drives behave exactly like hard disks
when it comes to their methodology of storage and block handling -- they
don't.

Yes. Smaller writes are much worse than larger writes.

The below may or may not be relevant to Hasso's situation, but I'm
chiming in regardless.

I did some testing of this nature on FreeBSD, using their new USB stack
in -CURRENT, specifically on USB flash drives. The old USB stack
performed horribly (and I've a feeling what's in DFBSD).

Here are the numbers:

http://lists.freebsd.org/pipermail/freebsd-current/2008-November/000271.html

Be sure to read the Points of Interest. Larger block sizes (above
128KB) performed equal to, or sometimes worse (!), than 128KB. Also
note the performance increase with 64KB blocks.

My point here is that yes, there's going to be a difference between
512-byte and 512-kilobyte blocks, but when it comes to USB flash drives,
there is in fact a "sweet spot".

Insofar as msdosfs goes the BIO's are done in msdos 'clusters',
which I think are around 4K.

USB flash sticks are one and two-chip solutions with virtually
    no buffering or smarts.  Trying to chase performance on these things
    is pointless.

-Matt
                    Matthew Dillon 
                    <dillon@backplane.com>