Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm looking for a clarification on SHR and how it handles expanding a volume when the volume contains varying disk sizes.

I've read the Synology Documentation and it still isn't clear, because their use-case assumes that the original volume was created with equal disk sizes.

My current volume setup on a DS411 is:

  1. 1TB
  2. 2TB
  3. 2TB
  4. Empty

I'm looking to add a 1TB disk to slot 4. Is this possible? I keep reading that the disk that is added needs to be "equal or larger than" the existing disks, but in my case, is that => the smallest disk in the current volume, or => than the largest disk in the current volume.

Would I be able to add a 1TB disk to my volume? Or would I need to add a 2TB or greater disk?

share|improve this question

related to SHR: yes, you can add so small HDD as is smallest in array = in your case 1 TB.

If I understand when you add to slot 4 next 1 TB HDD (expand SHR volume) you will have: 4x1TB in something like RAID 5 (that means 3 TB usable space) and thank to SHR also 2x1TB in something like mirror (means 1 TB usable space). By my mind final usable space will be 4 TB (or more precisely something above 3 "real computer TB" (correctly TiB) ).

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.