[GLLUG] Advice on expanding an existing RAID 1 installation

John Winters john at sinodun.org.uk
Mon May 26 19:20:41 UTC 2014

Dear all,

Thanks to many for some really good quality advice.

Having thought a bit further, and considered failure scenarios and how 
you back out, I've come up with the following:

1) Add a new 3TB drive to the RAID 1 array, and let it come up to speed.

2) Power down the system and remove *both* the existing drives.  This 
then means that if further actions hit a problem, I still have a good 
pair of drives as a backup.

3) Add in another 3TB drive, add it to the now degraded array, and let 
it come up to date.  This does rely on the (brand new) drive not hitting 
problems, but if it does then I have a sound back-out path.

4) Enlarge the RAID device.

5) Put the two removed drives in a safe place as an archive.

One potential issue with this is that if I want to read the old drives 
at a future date, I really can't put them back into the same system, 
because they appear to be failed drives from the same array.

I'll give it a go when the new drives arrive.


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