Comment 154 for bug 119730

On Wed, 2010-02-17 at 19:17 +0000, ivanxx wrote:

> I'm on an AMD64 2.6.31-19-generic #56-Ubuntu SMP and experiencing the
> same problem...
>
> Copying speed for some large files (2-12 Gb per file) from SATA to a USB
> drive drops to 1,4Mb/s after the first hundreds of Mb are copied. I have
> to copy around 1Tb, and I'm expecting it to take 8 days!!! It should
> take around 14 hrs at a decent 20Mb/s speed...
>
> Also the CPU wait states are around 50% all the time, thus the CPU use
> is 100% and load average 7.5... I suppose there's something wrong down
> in the kernel, perhaps the buffer for the first hundred Mbs not getting
> emptied/reused and everything slowing down after that.
>
> Ivan.
>

Please see post #12 and #14 of this thread
http://ubuntuforums.org/showthread.php?p=8769095#post8769095 if you are
copying to NTFS. This was amazing the difference it made. I don't know
much about how the ext3 fs works, but to sum up those posts, it depends
on how fragmented or non-fragmented the fs is when copying to NTFS. If
you are not copying to NTFS, then just ignore this solution, or read it
if you understand the workings of ext3 or others and perhaps it can put
you on a track that may be the problem with those fs.

Shane