Re: Slow USB disk
On Saturday 06 January 2007 03:45, Roberto C. Sanchez wrote:
> On Sat, Jan 06, 2007 at 04:31:27AM +0100, Benjamí Villoslada wrote:
> > KDE mounts USB disk with this options:
> >
> > /dev/sdb1 on /media/disk type ext3
> > (rw,noexec,nosuid,nodev,sync,data=ordered)
> >
> > And is slow. When I mount it manually, without sync option, then
> > write fast.
> >
> > I'm looking how tho modify the KDE mount in order to avoid the sync
> > option, but I don't locate this HOWTO. Maybe the Hal parameters?
> > Thanks.
>
> You might want to rethink that. The sync option is nice because that
> means that writes are completed immediately to disk. This is nice
> because it means that if you pull the disk out without umounting it,
> you are less likely to lose data (unless you do it while an actual
> data transfer is occurring). Without sync, the write could take an
> arbitrarily long time to be committed to disk, if there are not
> enough data to convince the driver to flush the cache.
But ...
... and there is a thread on the linux kernel mailing list about it ...
... you stand a chance of destroying the flash drive because of the
updates to the FAT tables during the write process. [I think someone
wrote a 1GB file to a large fat drive and fried it in the process]
What the grandparent post wants to do is controlled by HAL parameters.
Install the hal-doc package and then look
inside /usr/share/doc/hal-doc/conf for some examples.
--
Alan Chandler
http://www.chandlerfamily.org.uk
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