1 |
Am 24.10.2011 22:02, schrieb Grant Edwards: |
2 |
> On 2011-10-24, walt <w41ter@×××××.com> wrote: |
3 |
> |
4 |
>> I just bought an add-on USB3 adapter and outboard USB3/sata docking |
5 |
>> station, and I've been comparing the performance with my old e-sata |
6 |
>> outboard docking station. Not so good :( |
7 |
>> |
8 |
>> After getting some unreliable results with hdparm, I settled on |
9 |
>> copying one 3GB file from one partition of the outboard drive to |
10 |
>> another partition of the same drive. These results are highly |
11 |
>> reproducible, and favor e-sata over USB3 by a large margin. |
12 |
>> |
13 |
>> Over at least six trials on each docking station I consistently get |
14 |
>> 105 seconds for USB and 84 seconds for e-sata, a 5:4 ratio in favor |
15 |
>> of e-sata. |
16 |
> |
17 |
> Not surprising. Did you expect that adding a gateway device to the |
18 |
> communication path and another protocol layer on top of SATA would |
19 |
> make things faster? |
20 |
> |
21 |
>> I used the same hard disk and the same pci-e slot in the same |
22 |
>> minimally-loaded machine for all the runs, and got very consistent |
23 |
>> results every time. |
24 |
>> |
25 |
>> Basically, the USB3/sata docking station gets the same throughput as |
26 |
>> the older sata 1 drives connected to the onboard pci sata controller, |
27 |
>> which is still pretty respectable for an outboard drive, I think. |
28 |
> |
29 |
> Yep, SATA performs the same as SATA. AFAIK, eSATA and SATA are |
30 |
> identical apart from the physical specs for the connector, a few minor |
31 |
> voltage level differences (to imporove noise tolerance), and hot-plug |
32 |
> support. |
33 |
> |
34 |
|
35 |
Normal SATA also offers hotplug. Usually works, too. |
36 |
|
37 |
>> So, has anyone out there done similar tests on USB3 drives yet? |
38 |
> |
39 |
> There are disk drives that talk USB3 natively and aren't just using |
40 |
> USB<->SATA gateways? |
41 |
> |
42 |
|
43 |
Well, there is USB Attached SCSI (CONFIG_USB_UAS in the kernel). It |
44 |
supports command queuing and works for USB-2.0 and 3.0 (but has |
45 |
additional software overhead for USB-2.0). I've not yet seen a |
46 |
compatible device, though. |
47 |
|
48 |
Regards, |
49 |
Florian Philipp |