[ale] USB External hard drives

[Greg Freemyer]

On 8/1/07, David Corbin <dcorbin at machturtle.com> wrote:
> I've got a home file server that I run software raid on, because I'm lousy
> about making backups. It's an older system with IDE drives.
>
> I've had a recent failure, and  looking for a replacement. Some of the
> USB-based external drives seem to be available at good prices.  I also wonder
> if  they might do better in terms of survivabilty (instead  of being inside
> a "hot PC").
>
> Are the USB (2.0) external drives "fast enough", or will the USB a tremendous
> I/O limitation?

Are you seek limited, or throughput limited to your drives.

ie. lots of small files or database activity == seek limited

working with big files == throughput limited.

If seek limited, USB should be plenty fast.  I find with a simple
recursive copy I can do about 100,000 files an hour to a external usb
drive.  Same speed as directly connected via PATA.

If throughput limited, I have found USB 2 only does about 1GB/min. in
the real world, too slow for me unless I'm stuck.  (I have been using
the internal disk caddies, but then I have to reboot each time I
change data drives out.)

An eSata drive in an external enclosure should do close to 4GB/min,
but I have not yet made that jump.  I actually ordered some iRocks
esata enclosures today (less than $50) and some Seagate Sata drives
(from Fry's online).

Much to my chagrin we have 7 different kinds of MBs inhouse with
sata-2 capability.  About half support hotswap and half don't.  I want
to use hotswap on all of them, so I guess I will be buying some PCI
eSata controllers as well pretty soon.

HTH
Greg
-- 
Greg Freemyer
The Norcross Group
Forensics for the 21st Century