[CentOS] LVM, usb drives, Active Directory

Chan Chung Hang Christopher christopher.chan at bradbury.edu.hk
Wed Dec 16 14:34:56 UTC 2009


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


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