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Right now we have RAID 1 running on 2 1TB hard drives. They are nearly full so I would like to replace them with a 2 TB drive. Is there a master/slave with RAID 1? Am I able to just pull one of the drives and pop in a new drive, let the data replicate over to the new drive, then pull out the last old drive and replace it with the last new drive and let the data replicate over?

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up vote 3 down vote accepted

There is no master/slave in raid 1, any of the 2 disk contains a full copy of your data. However, if your RAID is of size 1TB, putting a 2TB disk will not increase the size of the array. Only half of your 2TB disk will be used in a 1TB array.

I don't know any method to increase the size of a RAID array. Best method I know is to create a new array with the 2 new disk and do a cold copy of the data from the 1TB array to the new 2TB array, then restart on the 2TB array.

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Some controllers will let you replace one drive, let the array rebuild/resilver, then replace the other drive, then expand the array to fill the new drive space. It's very hit and miss however, so definitely check the documentation for the specific controller/software in use. – Chris S Apr 4 '11 at 1:20

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