On Thu, 25 Mar 2010 14:10:05 +0000 John Robinson <john.robinson@xxxxxxxxxxxxxxxx> wrote: > > Part 1. > > > > A newly hotplugged device may have metadata for RAID (0.90, 1.x, IMSM, DDF, > > other vendor metadata) or LVM or a filesystem. It might have a partition > > table which could be subordinate to or super-ordinate to other metadata. > > (i.e. RAID in partitions, or partitions in RAID). The metadata may or may > > not be stale. It may or may not match - either strongly or weakly - > > metadata on devices in currently active arrays. > > Or indeed it may have no metadata at all - it may be a fresh disc. I > didn't see that you stated this specifically at any point, though it was > there by implication, so I will: you're going to have to pick up hotplug > events for bare drives, which presumably means you'll also get events > for CD-ROM drives, USB sticks, printers with media card slots in them etc. Correct. We would expect that "domain path=" matching to say that those should only be used if they already have recognisable metadata on them. To make use of a device with no metadata already present, it would need to appear at a path for which auto-rebuild was explicitly enabled. > > > A newly hotplugged device also has a "path" which we can see > > in /dev/disk/by-path. This is somehow indicative of a physical location. > > This path may be the same as the path of a device which was recently > > removed. It might be one of a set of paths which make up a "RAID chassis". > > It might be one of a set of paths one which we happen to find other RAID > > arrays. > > Indeed, I would like to be able to declare any > /dev/disk/by-path/pci-0000:00:1f.2-scsi-[0-4] to be suitable candidates > for hot-plugging, because those are the 5 motherboard SATA ports I've > hooked into my hot-swap chassis. > > As an aside, I just tried yanking and replugging one of my drives, on > CentOS 5.4, and it successfully went away and came back again, but > wasn't automatically re-added, even though the metadata etc was all there. No. That is because we have not yet implemented anything that has been described in this document... Thanks, NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
