On Tue, Dec 06, 2011 at 08:41:09PM +0100, Florian Philipp wrote:
> Am 06.12.2011 19:15, schrieb Todd And Margo Chester:
> >
> > Extra info. If I boot off a Fedora Core 16 Xfce Live CD, I
> > can copy my files to flash drive at full speed. It is a pain
> > in the neck, but it works.
I was a bit pissed b/c of a similar issue this week as well
(non-centos, ubuntu lucid, kernel 3.0).
checking mount options (async, stripping any remaining prehistoric
dirsync or other artefacts) and
cd /sys/block/sda/queue && ( echo noop > scheduler;
test -f rotational && echo 0 > rotational )
made it behave and restored _reliable_ writing.
[ current cfq is said to recognize flashes, but it doesn't for me
(rotational was still 1), worse: using cfq degrades to less than
100KB/s writes for me, 100% reproducible after copying a few GB (AFAIR,
always after copying 'more than physical RAM' GB, so it is some
kind of device-specific buffer reuse bug, maybe also vfat related
or related to flaky readers. However there's nothing in the logs).
]
Hth,
--
cu
Peter
[email protected]
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