On 2013-03-05, Brad Campbell [off-list ref] wrote:

I do keep a permanent spare drive, but with 3 arrays I manually allocate it in the rare event it is required. This drive had not failed out of the array, so the spare sat idle until I proactively replaced the dodgy drive.--

Are you using the spare-group attribute of arrays in mdadm.conf?  If so,
how well has it worked in your scenario?

--keith

-- 
kkeller@wombat.san-francisco.ca.us