Replacing tape changer with USB disk drives.

Oliver Fromme olli at
Tue Jun 17 15:40:13 UTC 2008

Wojciech Puchar <wojtek at> wrote:
 > > > 
 > > >  you must have something wrong. my USB drive gets 27MB/s. yes this
 > > >  480Mbit/s is USB isn't real, but half of it is.
 > > 
 > >       I agree.
 > >       Want to take this private and help figure out what's wrong?
 > > :-)
 > i simply have no idea why it could work so slow.

Cheap controller in the USB enclosure.  I've used quite
a few USB enclosures in the past years, and there are
significant performance differences.  As a rule of thumb,
the cheaper the box, the slower it is.  Of course there
are exceptions to that rule.

By the way, for backup purposes I use a hot-swappable
IDE drive frame.  The one I use is PATA (UDMA-133), but
there are also ones for SATA.  It's much faster than
USB and more reliable.  You can use atacontrol(8) to
attach and detach the drive while the system is running.
(For that to work reliably, the frame must be the only
device on its channel, i.e. no slave, in the PATA case.)

Best regards

Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

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