[CentOS] Removing a disc from a software mirror

[Joseph L. Casale]

>I'm not sure if this is a timestamp or a count of clean shutdowns.  Does
>anyone know?

Well, the setup wasn't mission critical or I would have imaged it out safely so I proceeded to shutdown the machine and unplug the secondary drive. I then booted and saw the array obviously had a missing component. I did my reconfiguration and it was good. I shutdown, plugged the secondary back in and then booted. The arrays didn't automatically re-establish the pair(?), so I # mdadm /dev/md0 -a /dev/sdb1 and # mdadm /dev/md1 -a /dev/sdb2 as md0 is the /boot partition and md1 is the LVM pv that holds swap and /. It all went well as I had # watch -n1 'cat /proc/mdstat' running.

Not as slick as the higher end machines with hardware raid and hot swappable back planes but it saved me either waiting for a painfully slow dd of the disc or a re-install if what I did failed.

Thanks everyone!
jlc