USB 3.0/2.0 disks are currently the cheapest (at least for 4tb).. I've uncased a few, Preclear'd them and they are working quite well. I want to add more. However the problem is that if I uncase a disk the warranty is gone..If there is a problem with the disk, its $ down the drain..

 

Is it possible to add the disk via usb to preclear them? If they pass then uncase them and put them in the server.. If they fail return or submit under warranty..

 

Thoughts?

If you plug the disk into the USB port it should show up as a device under /dev/disk/by-id

 

in addition,the preclear script should show it  when you type

preclear_disk.sh -l

If it shows up, you should be able to preclear it in its case via USB-3.

(who knows how fast it will be... you'll have to tell us once you try  it.)

If it does not show up when you type

ls -l /dev/disk/by-id

then lunix is not seeing it.

My experience is that it will work, but it is so slow it makes absolutely no sense to do it if you have any choice.

 

I precleared two new 2TB WD Green drives a couple weeks ago. I have one free hot swap SATA dock in my case, so I slapped the first drive into that and began preclearing it. Then I thought I would preclear the second one simultaneously using a SATA/USB 2.0 interface adapter I have on hand. I plugged it into a USB 3.0 port and was able to begin preclearing on second console session.

 

But I gave up very quickly as I discovered it was several times slower than the direct SATA interface. There was no point in continuing, as it would take much longer that way then to wait for the first drive to preclear and put the second drive into the dock. What I did instead was open the case and hot plug the second drive into an open SATA port, since my MB is new enough to support hot plugging. That way the second drive finished preclearing about 45 minutes after the first, instead of two days.

 

With a USB 3.0 interface it should be faster, but I doubt it would be anywhere near a 6 gb/s SATA port.

If it works okay, I suspect the time is irrelevant -- it at least provides a means to thoroughly test the disk before removing it from the casing.

 

However, since the reason it's so slow is the lack of USB3 drivers, there's another alternative for testing the drives.  Just plug them into a Windows PC and run WD's Data Lifeguard.  Do the quick test; then the extended test;  then write zeroes to the full drive; and then repeat the first two tests.    If a drive does all this error-free, it's safe to assume it's a good drive.  You may still want to run a pre-clear cycle on the Linux box if you have time to just let it run .. but the Windows tests will be at USB3 speeds, so will be far faster.

 

There may also be some USB3 drivers you could add to the UnRAID flash drive, but I'm not a "Linux guy", so somebody else would have to detail how to do that.