Expanding SHR with smaller disks


Quick question.

Can I expand volume capacity using smaller disks but by ADDING new disks (pairs) if I have got SHR?

I know that if you REPLACE disks then you need same or bigger size but here I will just add empty disks.

I need to run DS1821+ in steps:

  1. Add first disk 16 TB
  2. Copy data
  3. Add second 16TB (here we have SHR with 1 disk protection)
  4. Add 8+8TB and 4+4+4+4TB
  5. Rebuild everything.

Will it work as I think?

No. You can however create a new, second, SHR pool/volume with smaller drives. Read the Knowledge Center write-up. When expanding SHR volumes, added drives must be equal to or larger than the largest existing drive.

Otherwise, begin with the 4 TB drives, then add the 8s, and finally the 16s.


So even adding new empty drives, new drives must be same/bigger size.

So if I want to achive one big volume, I need add 4x4TB drives, then 2x8TB drives, then copy data from 16TB drives and…finaly erase 2x16TB drives and add them as last ones…

Thank you. You saved me a lot of trouble.

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So i used the synology raid calculator online selected shr for my ds1522+. I purchased two 8TB drives to get started. I am now up and running and wanted to verify this is okay after what i just read above.
I have a matching drive by brand and series but just the 6tb version. Can i not add this to my shr? If not, what is the reason at a technical level.
My drobo-fs would allow this.

Thank you.

You cannot expand current shr volume. You can make another pool/volume with 6TB drives.

But maybe you can make new pool/volume 6TB, then copy all data from 8TB (use Data Migrator or HyperBackup), then erase 8TB drives and use them as extensuon to 6TB pool/volume drives. As 8TB drives are bigger so you can expand 6TB pool/volume.
Finally you should have almoat 20TB space with SHR-1