Moving files from ext2 to FAT32 under FC3 is VERY slow!

[Hervé Pagès]

Thanks for the answers and suggestions.

I tried booting with the last KNOPPIX (3.7) live CD using 2.4.27 kernel
and did some benchmarks:

  - copying files from /dev/hda2 to /dev/hdd10 = 16 MB/s

  - copying files from /dev/hdd10 to /dev/hda2 = 26 MB/s

Reminder:
  /dev/hda is a Seagate Barracuda 120GB/7200rpm/8MB cache ST3120026A)
  /dev/hdd is a Seagate Barracuda 80GB/5400rpm/2MB cache (ST380021A)
  /dev/hda2 is ext2 and /dev/hdd10 is FAT32

As you suggested Jeff, it seems clear from the above benchmarks that the
writing speed of the target disk can be a bottleneck.

Also tried booting KNOPPIX with the 2.6.9 kernel:

  - copying files from /dev/hda2 to /dev/hdd10 = 14 MB/s

  - copying files from /dev/hdd10 to /dev/hda2 = 20 MB/s

Apparently the 2.6.9 kernel is slightly slower! (I was not expecting
that.)

As for my very SLOW file transfer problem under FC3 (2.4 MB/s)
I just realized that I was booting with ide=nodma :-(

I had to use this option when I booted from my FC3 CD1
otherwise the mediacheck would fail. I can't remember then
if the FC3 installer put that ide=nodma boot option in my
grub.conf file for me or if I had the very bad idea to
do it myself.
The fact is I have been booting my system with this nasty
option since the first day I've installed FC3. And it remained
here even after several kernel updates (I'm currently with the
2.6.9-1.681_FC3 kernel). I can't blame the kernel packagers
for that: they are doing a nice job by replicating the kernel
parameters introduced by the user (even nuts ones) to the new
entry in grub.conf. This is all my fault!

So after removing the ide=nodma everything works FINE.
Benchs are now:

  - copying files from /dev/hda2 to /dev/hdd10 = 19 MB/s

  - copying files from /dev/hdd10 to /dev/hda2 = 23 MB/s

It's interesting to compare the FC3 vs KNOPPIX benchs (both
with DMA enabled):

  - FC3/2.6.9 vs KNOPPIX/2.6.9: FC3 is faster

  - FC3/2.6.9 vs KNOPPIX/2.4.27: FC3 is faster for the
    hda2->hdd10 copy but slower for the hdd10->hda2 copy


Cheers,

Hervé