On Tue, Oct 29, 2013 at 2:45 PM, <tclug at freakzilla.com> wrote: > Ok, so right now I have a RAID5 array I created with mdadm. It uses four > identical HDDs, one of which is a spare obviously (which is good because I > had one fail). > > Anyway, sincethe enclosure I use can support 8 drives, I'm getting four more > HDDs (also identical to the first) and plan on adding them to the current > array. > > Now my hopefully silly question is, do I have to do anything special while > adding them, or does mdadm/whatever know which to add as "live" data and > which to add as spares? Can I just go "mdadm --add /dev/md0 /dev/sdf1" (and > then sdg1, sdh1 and sdi1)? Or do I have to do anything special? when you do that you will add those drives as spares, you will then have to restripe using something like: mdadm --grow /dev/md0 --raid-devices=4 (since your raid deviced is currently 3) and while you can probably go directly to 7, or 8 i would recommend being patient and doing it one at a time.