[NBLUG/talk] Final verdict for USB/RAID combo: dismal failure

[Lincoln Peters]

While I found that it was possible to create a RAID array out of hard
drives attached to a USB controller, I ultimately found it to be too
complicated and too unreliable for general use.  Specifically:

* No matter what I tried, I couldn't get the RAID kernel modules to
recognize the USB hard drives without my manual intervention, resulting
in at least one "DegradedArray" event every time I rebooted the
computer.  Perhaps this wouldn't have been an issue if both of the
drives I used for the root filesystem array had been in the tower (one
was in a USB enclosure), but even so, it still certainly complicated the
boot process.

* It was not at all a simple matter to do any sort of health checks on a
hard drive in a USB enclosure.  For one thing, I found that I could not
do S.M.A.R.T. monitoring on a drive in a USB enclosure, even if the
drive supported S.M.A.R.T. monitoring.  Somehow the enclosure seemed to
cause all S.M.A.R.T. checks to fail.

* Unless you can clearly establish the order in which devices are
detected on a USB controller, there would be a possibility that, if I
were to reboot under a condition even as simple as having a USB floppy
drive plugged in, the drives would register in the wrong order and the
array would fail to start without manual intervention.

* I had the issue with occasional USB controller failure, which I have
yet to resolve.  The failures are very infrequent, so it's hard to know
if I've made any progress yet.


I've moved all of the hard disks back into the tower, and after jumping
through a few hoops in order to get the drives assigned correctly,
everything now seems to be working again.  RAID, in and of itself,
doesn't seem to have any issues; it was only when I tried to add USB
enclosures to the equation that everything went crazy.  Perhaps some day
it will be possible to assemble reliable RAID arrays using drives
attached to USB and/or FireWire, but not today.

---
Lincoln Peters
<sampln at sbcglobal.net>

Perhaps the remembrance of these things will prove a source of future
pleasure.
		-- Virgil