[lug] hotswap sw raid mirror

[dio2002 at indra.com]

> On Fri, Jul 27, 2007 at 02:49:30AM -0600, dio2002 at indra.com wrote:
>>i obviously don't expect to be able to just pull a drive on a running
>>array and expect that to work.  that's hw raid turf.
>
> What do you have to lose in pulling a drive and seeing what happens?

I don't know, that's why i asked it in the last post because i don't know
the answer.  i think in a roundabout way you're saying there's no harm to
hw or the installation (assuming i degraded the devices before pulling)
right?

>>but i was thinking that while testing recovery scenarios, i could fail
>> one
>>device in the mirror, stop the array and then pull the drive while the
>
> You will have to fail all partitions that are on the device you want to
> pull.  See the man page for "mdadm", in particular the "--fail" and
> "--remove" options to Manage mode.  You can fail a device in the array
> without shutting down the array.

ok.  understood. so failing is enough. back to the original question. if i
fail all those partitions i can pull the drive on the live system and md
will be smart enough to move those partitions to the 'removed' state right
(or must i also remove them via mdadm Manage mode --remove before
physically taking them out)?

fwiw, i shutdown earlier, pulled the 2nd drive and booted.  right now my
system is up with active arrays that have the mirrored devices listed as
State --removed which is the exact opposite situation i described above. 
Which means i should be able to insert the pulled drive on the live
system, use manage mode -a (add) command to add the partitons back, and
then let md resynch as needed and be back i business.  right?