USB RAID Controller

I agree with leew, plus i suggest using an external esata raid enclosure so the drives stay together and only 1 esata cable would be required(multiple cables will usually end up causing headaches).
http://www.newegg.com/Product/Product.aspx?Item=N82E16817256018

I understand your comments regarding the USB 2.0 speed, however the solution I am working on needs to use 2.5" bus powered external hard drives.  So I need a controller to pull these drives together in RAID 5.  USB 2.0 is the only bus powered solution for external 2.5" drives I am familiar with, maybe there are others?

Bill

MAYBE you can use something like this:
http://www.addonics.com/products/flash_memory_reader/ae4udd.asp

Otherwise, powering 3 drives from the USB bus could put a strain on your system's power supply.

And keep in mind that even external 2.5", often require the power from 2 separate USB ports to work properly.

Using USB for what that purpose wouldn't be too reliable.

Carlos,

Yes I am aware of this - per MS website, the USB 2.0 spec is for max power not to exceed 500mW.  Many 2.5 inch drives operate above this level.  I am only using those at or below 500mW power consumption level.

Bill

>>I am only using those at or below 500mW power consumption level.

This sounds like an interesting project, but there is no commercial solution available yet.

Maybe if you define your problem, we can help you with a solution, since there are some external usb solutions that have Raid1 capablity, but they need external power.

(Netgear 101  comes to mind.)

arthurjb,

I am unable to disclose the details of the system I am working on, but I think you are right that no commercial solution yet - thanks for your comments.

Bill

You don't have to reveal too many of the details to get a better answer.

So here are a few questions that might help.

Is it the small size of he usb or do you just not want to use an internal raid card?

Is the lack of an external supply just a nice thing to have, or 100% necessary?

Is there a reason you cannot use an external raid box that is built for the purpose?

arthurjb,

Is it the small size of he usb or do you just not want to use an internal raid card?
Need small low energy consumption external drives

Is the lack of an external supply just a nice thing to have, or 100% necessary?
Nice to have

Is there a reason you cannot use an external raid box that is built for the purpose?
Yes - there is a reason (confidential)

Bill

If you are stuck having to use windows, then I am not sure if there is a solution.

But, if you can use Solaris, you may be able to use the Disk Suite tools to use several of the drives as part of a raid set.

It seems like an interesting project, tomorrow I am going to try using a usb drive under disk suite, and let you know the results.  (I would do it now, but I don't have a Solaris machine here.)

Of course, the main reason to use raid is to provide data protection from a disk drive failure.  With the cost of solid state drives dropping, you may be further ahead to see if you can use solid state drives to meet your goal.  Since a failure of the solid state drive is much less likely, it may eliminate your need for raid, and reduce your power budget...

Makes me think about a software RAID with USB. I would not use any other RAID level than 1 due to potential breakage and need to rebuild a 0 or 3, 5, 6, 10 and so

USB bus is simply to unreliable to trust in a real RAID 5 scenario

Forced accept.

Computer101
EE Admin