Steve Thompson wrote:
On Wed, 16 Dec 2009, Chan Chung Hang Christopher wrote:
Steve Thompson wrote:
On Tue, 15 Dec 2009, Scott Ehrlich wrote:
I have a client with a handful of USB drives connected to a CentOS box. I am charged with binding the USB drives together into a single LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap storage in a single mount point).
I tried doing this for fun once upon a time, using 6 1TB drives. I can save you a lot of grief by suggesting that you don't think about this any further. Boy is it slow. And extremely unreliable. And slow. Don't even do it for backups. Did I say it was slow?
Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or slowaris slow?
Slower than all of those. Top write speed I could ever achieve with a USB-2 interface and SATA drives was 20 MB/sec with a trailing wind, and usually half of that, with a single stream. I even tried USB-1 for more laughs; 1 MB/sec on a truly good day. With multiple writers, performance dropped so far as to be unusable (below 1 MB/sec). And we're talking mkfs times in _days_. The host was a CentOS 5.2 box, 32-bit.
Kudos to Steve for proving that USB2's 480mbits/sec is really just a sham.
Now I wonder if you can daisy chain IEEE1394 devices...or try out eSATA...:-P