Linux Raid: Can mdadm --grow a raid1 while mounted?

Posted by Chris on Server Fault See other posts from Server Fault or by Chris
Published on 2010-12-23T15:05:14Z Indexed on 2010/12/23 15:55 UTC
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linux

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raid

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mdadm

I have 2 500gb drives in a RAID1 setup that I needed to upgrade for more space. I mdadm --fail'ed each drive in turn and I used dd to copy each drive to it's respective larger drive (2tb each), removed the smaller drives and replaced them with the larger drives, and reassembled the array and forced a resync. So now I've got a 500gb RAID1 sitting on 2TB drives, and wish to grow them.

The plan is to use mdadm --manage /dev/md0 --grow to grow them, then boot a rescue cd, assemble the array under that environment, and do the resize2fs on them. Can I use mdadm --grow on a mounted and live filesystem? Also, do I need more options to make sure the grow operation stays raid1?

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