Ley's say I have an unRAID system consisteing of a 500GB parity drive and two 250GB data drives.  What would be the safest/best way to consolidate the two 250GB drives to a single 500GB drive?  Should I copy the data from the two 250's over to the 500GB drive and then remove the two 250's, or should I remove a 250, add the 500, perform parity sync,  and then remove the last 250?  Ultimately, I'm trying to replace trwo drives with one.  Has anyone done this already?

The easiest thing to do would be shut down the server remove one of the 250GB drives and replace it with the 500.  Reboot and let unraid recreate the data to the new disk.  Then copy the data off the other 250 to the 500 shutdown remove the second 250 and reboot.  Now you need to run a parity sync with your one drive to protect the array.

Probably the fastest way to do it is this:

 

1. Save a copy of 'config/super.dat' - this file holds the array config (that is, which hard drives are parity, disk1, disk2, etc, along with state info such as whether parity is valid).

 

2. Power down, add your 500GB hard drive, power up, go to Devices page.  Add the new drive to the configuration and remove the parity drive from the configuration (just mark parity 'unassigned').

 

3. Click start - array should come right up - click Format to format the new drive.  Once this is done you may now access the new drive either via network share, or locally.

 

4. To copy all files from say disk1 & disk2 to disk3, use a command like this in the telnet window:

cp  -r  /mnt/disk1/*  /mnt/disk3
cp  -r  /mnt/disk2/*  /mnt/disk3

 

5. Now if you're intending to remove the two smaller drives, Stop array, power down, remove them; then power up, go to Devices page, reassign parity, go to Main, click 'Restore config', click Start - this will start parity sync.

 

If something goes wrong along the way, or you want to get back to the original config, just restore the copy of 'config/super.dat'.  As long as disk1/2 have not been written with user data, parity will still be valid.

 

Make sense?

Thanks for the tip Tom (one to add to the wiki).  I've faced the same problem several times (trying to move/consolidate data) and wondered how you might make the process go more quickly.