Ok, here's the deal.  I have several drives of small sizes, and long age, that I want to pull out and replace with bigger, and new drives.    (5.0-beta14)

 

Basically:

 

1) Replace my parity drive with a 3TB one  {current parity is 2TB}

 

2) Replace a 500, 500, 750, 1tb drives with two new 2TB drives - old drives to be removed permanently

 

3) Re-purpose my old parity drive (2TB) as a data drive

 

Proposed steps:

a) Run Preclear on new drives -- check..  I have run pre-clear for 3 passes on all the new drives (3TB plus both new 2TB drives)

 

b) Shutdown - Remove the parity drive, reboot -- let the system 'fault' -- and rebuild parity on the new 3TB drive.   

 

c) Re-run parity check two times -- if any failure of parity check,  then put back in the original parity drive and "trust my array" and figure out what's going on

 

d) Shutdown, add the two new 2TB drives, reboot - add drives to the array {expand the array}

 

e) Use Midnight Commander or Terracopy to copy from \\unraid\disk7\*.* to \\unraid\disk15 (7=old, 15=new) -- or as required old/new pairs.

 

h) Shutdown, Physically remove old drives. 

 

i) Boot unraid -- will fail because of missing drives.  Do "trust my array"...  (initconfig) let it rebuild parity

 

j) Re-run parity check two times -- if parity check fails, I have the old drives still {with data copied from, not moved} and the old parity drive -- could go back to square one.

 

j) Last step -- shutdown, insert old Parity drive, reboot - add old Parity drive as a data drive.

 

k) Sell old drives on eBay  

 

 

Am I missing any steps -- or a better way to do this?

 

 

 

I think there are some extra steps in there and some redundancies.

 

Between c) and h), now that you have already rebuilt the parity and did the parity check twice, you should really trust the contents of the new parity and why not just replace the old data drives with the new ones and rebuild them from the new parity?

 

Because when you perform step i), you are negating all the benefits of step c). You are pretty much rebuilding the parity all over again without using the parity data from step b), so there would be no reason to do 2 parity checks in step c) if you're going to perform step i).

 

If you do it the way you proposed, you will not be checking to see if there was data corruption during transfer. Because essentially what you're doing is: 1) copy contents of old drive to new 2) build new parity with contents of new drive 3) perform parity check between new parity and new data

 

If the data was altered during step 1, you will have no idea, because the parity check in step 3 will compare the data on the new drive to the parity built from the new drive contents, not the old.

 

As I mentioned earlier, I would replace the parity with new, rebuild parity, do parity check. Then replace one data drive, rebuild from new parity, do parity check. Then replace another data drive, rebuild from parity, do parity check. That way, you are only changing data on one drive at a time, and making sure that the changes were done correctly at every step without redundancies.

 

But then you would have to remove two of the older drives, and in that step you would have to copy contents over to the new drives. If you're really paranoid, I would suggest using some software to compare the destination and source files to make sure they weren't altered during the transfer, because when you rebuild parity after that you won't be able to check that through parity checks anymore as the parity data will be based on data on the new drive and any corruption will exist on both.

 

Just my 2 cents

If you're really paranoid, I would suggest using some software to compare the destination and source files to make sure they weren't altered during the transfer, because when you rebuild parity after that you won't be able to check that through parity checks anymore as the parity data will be based on data on the new drive and any corruption will exist on both.

 

Just my 2 cents

 

I haven't used Midnight Commander -- but I know Terracopy can do the "check" after the copy.  I don't mind the time.

 

I'll parse through your notes and see what I ought to add/change in my process.

 

And in the interim, if anybody else has comments -- most appreciated.

 

This is probably the most significant change/rebuild I have done on my unraid.

 

~Update:  And I guess, it might be better to see if I can combine two of my drives (see if I can squeeze in my two 500s into the existing space) so that I'm really replacing 3 drives for 3 drives -- and using parity to rebuild them.