On Sun, 8 Dec 2013 16:45:08 -0600 hai wu <haiwu.us@xxxxxxxxx> wrote: > Thanks Neil. I am not sure if I understand mdadm 'spare' correctly. If > doing as you mentioned above, the new driver will show up in output of > "mdadm --detail /dev/md0" as 'spare' status, while I would like the new > drive to automatically show up as "acitve, sync", and it will automatically > be synced up with the one remaining good drive upon running the udev rule. > I don't see an option like "force-include" in this case. Please let me know > if I miss something. Whenever md notices that an array has a spare device and a missing device it will start rebuilding the spare and will then make it an active device. So if a new device is added to the system, you really do want to give it to md as a 'spare'. md will do the rest - it always has done. NeilBrown > > > On Sun, Dec 8, 2013 at 3:55 PM, NeilBrown <neilb@xxxxxxx> wrote: > > > On Sun, 8 Dec 2013 11:53:00 -0600 Hai Wu <haiwu.us@xxxxxxxxx> wrote: > > > > > I am wondering whether it is possible for mdadm to auto-rebuild a failed > > > raid1 driver upon its replacement with a new drive? The following lines > > > from some RedHat website URL seems to indicate vaguely that it might be > > possible: > > > > > > > Yes and no. > > "yes" because it is certainly possible to arrange this, > > "no" because it isn't just mdadm which does it. > > > > When a drive is plugged in, udev notices and can run various commands to do > > things with that device. You need to get udev to run "mdadm -I $devname" > > when a new device is plugged in. > > The udev scripts which come with mdadm will only do that for new drives > > which > > appear to be part of an array already. You presumably want it to do that > > for > > any new drive. The change should be quite easy. > > > > Secondly, you need to tell mdadm that it is OK to add a new device as a > > spare > > to an array. To see how to do this you need to read the documentation for > > the "POLICY" command in mdadm.conf.5. > > > > A line like: > > POLICY action=force-spare > > tells mdadm that any device passed to "mdadm -I" can be added to any array > > as > > a spare. You might not want that, but you can restrict it in various ways. > > > > POLICY path=pci-0000:00:1f.2-scsi* action=spare > > > > says that any device attached to a particular controller can be added to > > any > > array as long as it is already a member of the array, or appears to be > > blank. > > > > There are various other directives which should allow you to describe > > whatever you want. > > > > NeilBrown > > > > > > > Previously, mdadm was not able to rebuild newly-connected drives > > > automatically. This update adds the array auto-rebuild feature and > > allows a > > > RAID stack to automatically rebuild newly-connected drives. > > > > > > The goal is to get mdadm software raid1 to behave the same as hardware > > > raid1, when replacing failed hard drive. It should automatically detect > > new > > > drive and rebuild the new drive into part of raid1 ..-- > > > 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 > > > >
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