[Gllug] Backup drive for CentOS 5 remote setup

[Andrew Farnsworth]

On Tue, Aug 17, 2010 at 4:41 AM, t.clarke <tim at seacon.co.uk> wrote:

> Is the 'need a short lead' problem with the USB drive due to the fact it is
> powered from the USB lead ?
>
> Personally I always go for USB drives that are externally powered; I know
> this
> means an extra plug and power cable, but the USB-powered ones must surely
> draw
> a fair bit of juice from the lead which may well limit what else you can
> connect
> to the USB hub at the same time (?)
>
>
Power to the USB drive is limited by the USB standard to 500 mw or 1/2 a
watt.  If you are using a short chunky cable as opposed to a long thin one,
I would suspect the long thin one doesn't actually have the power wires and
is really just a 2 wire cable... not really a USB cable at all.  You could
check this with a multimeter pretty easily or try the same cable with
another USB powered device that uses less power.

If you are running the drive off a server, you should not have to worry
about USB power as each port should supply up to 500 mw.  if you are
connecting these devices to a laptop that is not plugged in... then I would
worry.  Or if you were plugging them into an unpowered USB hub.  A powered
USB hub should supply 500 mw to each port... well the good ones anyway.

Andy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.lug.org.uk/pipermail/gllug/attachments/20100817/63a2fb5f/attachment.html>
-------------- next part --------------
-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug