restore of file system into USB key terrible slow

[Bernd Walter]

On Tue, Aug 05, 2008 at 05:06:09PM +0200, Oliver Fromme wrote:
> Matthias Apitz wrote:
>  > [...]
>  > > I'm trying to restore a DUMP into an USB key; the DUMP was extracted
>  > > from another USB key which I just want to colne this way;
> 
> Note that dump/restore isn't a very fast method to clone
> a file system.  Actually, a few years ago it was horribly
> slow, but it was improved somewhat.  It's better now, but
> still not very fast.

Additonally some flash devices are horribly slow when it comes to
many small random writes, which writing many small files does.
Internally they do read modify writes on physically larger blocks.
It is often much faster to do the FS work on an image and then dd
the image to the USB stick using 64k to 256k transfers.
MLC flash devices are typical candidates for being extremly slow
with small random writs.
If speed is an issue you should take care and invest in the higher
price to buy SLC devices.

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.