James Bensley wrote:
I have read a few articles about mdadm and I have devised the following strategy in my head and am looking for some confirmation of its theoretical success:
Two of my existing three drives are full of data. I will purchase two more drives to go with my existing blank drive and set them up as a RAID 5 > copy my existing data on to the new file system one drive at a time and after each drive has been copied I will add said drive and use mdadm --grow to then incorporate that drive into the RAID before adding the next drive. Can anyone point out a flaw in this plan or more preferred method for doing this, or have I, dare I say it, got it right?
growing raid-5 by adding drives is an inherently dangerous operation as every single stripe of the raid has to be reorganized, and can take hours or even days.
http://linux-raid.osdl.org/index.php/Growing
I prefer wherever possible to build a new raid, copy the data, and when I'm assured the copy is correct, re purpose the old drives.