Les Mikesell lesmikesell@gmail.com wrote:
OK, but "raw" scsi disks don't have this problem.
Huh? Unless the device is unmounted and not in use, you betcha you'll have the _same_ problem. The kernel panics because the device is no longer available.
Only when you have a SCSI hardware RAID array will you get the same functionality as 3Ware hardware RAID arrays.
Why is this different than a scsi drive?
It's not.
Of course we don't understand it. Is this documented somewhere?
Sigh. Please show me where it is documented that you can remove _any_, _active_ storage device from a system without it kernel panicing? The only time I can remove _any_ storage device (without configuring advanced hotplug features) is if I take the device off-line.
That's just how the kernel works, _period_.
3Ware physically "hides" the storage devices, but _only_ when you make them an array. As long as the array is intact (be it good or degraded), it is still usable by the OS. The 3Ware is controlling _all_ disc activies, and only reports itself as an array back to the OS.
When the OS sees the "raw" storage, then that's a problem if one part of the storage becomes in available. Such is the case of _any_ storage that is "removed" because it fails -- be it a physical ATA drive on an ATA controller, a physical SCSI drive on a SCSI controller, or any controller that presents a disk as a standalone JBOD volume.
You have to setup something like hotplug to take control of the device, so when it goes off-line, the system doesn't see it, while it's still trying to use it like it's there.