Synology Remove a 4TB from a RAID

Thought I would share an experience recently about Synology that I have completed.

I have two different Synology. A DS1511+ and a DS1813+.

In my DS1511+, here’s the set up:

Disk 1 : 1x4TB (don’t ask me how it ended up there.. must be one of my Amazon purchase went wild and then wrong)
Disk 2 to Disk 5 : 4x3TB

In my DS1813+, here’s the set up:

Disk 1 to Disk 5 : 5x3TB as volume 1
Disk 6 to Disk 8 : 3x3TB as volume 2

I was running out of disk space in DS1813+ where the volume 2 is running out of space. So I would like to add two 4TB to it to expand it. That’s the lowest (cheapest) possible method to add 1TB more to that volume.

Now I saw that in my DS1511+, there is this weird arrangement of 1 piece of 4TB with 4 pieces of 3TB. Even when you play with Synology RAID calculator and even though I am running SHD, it is 1 TB of waste space:

RAID Calculator DS1511

So I thought, can I actually used it…. I decided to try. I took a 3TB lying around and then removed the 1x4TB (Disk 1) from the Synology DS1511+. Of course, the RAID goes to a degraded mode immediately:

Synology Degraded Mode

So I gingerly plug in the 3TB (that was lying around) into Disk 1 and pray like mad :)
Synology Degraded Mode Repair 1

Once I see that the repair method was able to go ahead, I am much more optimistic that this will work.
Synology Degraded Mode Repair 2

Synology Degraded Mode Repair 3

After 24 hours, it completed !
Synology Degraded Mode Repair Completed

So in summary, I managed to remove a 4TB hard disk from a RAID (which consist mainly of 3TB and by the RAID method, the 4TB was wasting 1TB of space) and replace it (without any downtime) with a 3TB hard disk.

Thus freeing up my 4TB to be used on my DS1813 (Of course, I need to procure another 4TB hard disk).
DS1813 Volume 2

photo credit: Bits via photopin (license)

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