which disk to replace to expand raid.

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which disk to replace to expand raid.

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ds1850+ rs422+
Ok, so I made a mistake, and learned by reading about it here:

Background, had a disk setup like this:
bay1: 20tb
bay2: 20tb
bay3: 2tb
sum 22tb

Replace the 2tb with 6 tb
bay1: 20tb
bay2: 20tb
bay3: 6tb
sum 22tb

so sum didn't change obviously, but thought by adding another 6 tb i would be able to utilise that new disk space, so currently it looks like this:
bay1: 20tb
bay2: 20tb
bay3: 6tb
bay4: 6tb

But the sum is still the same. Frustrating, solution would be to add a disk that has the 20TB capacity, that should solve this. But at the same time i would like to gain the disk space of at least one of the 6tb. Is that possible and if so, which one? This is how it looks like on low level raid setup:
md5 : active raid1 sdg6[0] sdh6[1]
17578305856 blocks super 1.2 [2/2] [UU]

md4 : active raid5 sde5[4] sdf5[3] sdh5[2] sdg5[1]
5828362752 blocks super 1.2 level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md1 : active raid1 sde2[1] sdf2[0] sdg2[7] sdh2[6]
2097088 blocks [8/4] [UU____UU]

md0 : active raid1 sde1[1] sdf1[0] sdg1[7] sdh1[6]
2490176 blocks [8/4] [UU____UU]

Or do I need to create a new volume and start all over? Any help would be appreciated since moving around 20TB of data aint fun..
 
In the initial setup your volume was using one of the 20TB drive as a redundancy drive. This will not change even in the 4 drive setup (20x20x6x6). The point is that single drive redundancy needs to cover the single largest drive of the array and that is a single 20TB.

Also, raid calculator will only show what the setup will initially look like, not how it will look like after you have data on it and then start swapping the disks out.

So yes, in this case, backing up and starting fresh will give more room, but you have to be ready for 2x20TB transfers.
 
In the initial setup your volume was using one of the 20TB drive as a redundancy drive. This will not change even in the 4 drive setup (20x20x6x6). The point is that single drive redundancy needs to cover the single largest drive of the array and that is a single 20TB.

Also, raid calculator will only show what the setup will initially look like, not how it will look like after you have data on it and then start swapping the disks out.

So yes, in this case, backing up and starting fresh will give more room, but you have to be ready for 2x20TB transfers.
Thank you for your response, but I am not sure I understood the answer.
I do understand the current situation, but what happen if I replace which used to be the third and last drive in the original setup. From the md report that drive is set to be a raid 5 part of the raid 1 20TB disks:
md4 : active raid5 sde5[4] sdf5[3] sdh5[2] sdg5[1]

If I change that to a 20TB, I would have a 40TB raid. The joker is the forth disk, what would happen to that one? Just an appendix?

Or what happen if I change the forth disk? I would assume i would end up with a 40TB volume plus the third disk with the original size of 2TB even if its a 6TB disk.
 
It won't matter that much as your current array is registering 4 drives not 3. So, as long you add one more 20TB then you will see a bump (or a larger one).
Ok, Thank you for the response and input. Then I see no other solution then to create a single SHR1 volume from a new 20TB disk. Copy it all over and when it's done expand that volume with the 20TB disks from old volume. Frustrating to say the least.. :) I hope this thread can help someone else before ending up in my situation..
 
Well using different size drives (especially with that much difference in size) will lead to situations like this... Maybe use the Control Panel > shared folder move option so you don't have to copy the data. It will be faster.
yes, will definitely use the move function, its way faster. I just hope it can move my VMs running too.

This is indeed what happens when you trying to be cheap. You end up paying anyway, just later and probably with more money and more work. Should have just bought the third 20TB from start and created the raid with three disks and not installed any old disk.
 

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