Replacing tape changer with USB disk drives.

[Oliver Fromme]

Wojciech Puchar <wojtek at wojtek.tensor.gdynia.pl> 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

-- 
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

FreeBSD-Dienstleistungen, -Produkte und mehr:  http://www.secnetix.de/bsd

"It combines all the worst aspects of C and Lisp:  a billion different
sublanguages in one monolithic executable.  It combines the power of C
with the readability of PostScript."
        -- Jamie Zawinski, when asked: "What's wrong with perl?"