I have a Synology setup using SHR-2, originally populated with 22TB drives. I recently replaced 5 of these 22TB drives with 24TB ones. The storage pool, which includes these drives, hosts two volumes: a regular volume and an encrypted volume.
Here’s a breakdown of the current status:
The storage pool now has 5.4TB of unused space.
The regular volume offers the option to expand by 5.4TB.
The encrypted volume does not present the option for expansion.
I suspect this issue arises because SHR-2 has created a second underlying RAID-6 to handle the larger drives, and it seems encrypted volumes cannot yet take advantage of the new space created by this RAID configuration.
My Questions:
Does anyone know if Synology is actively working on a fix to allow encrypted volumes to utilize the new space in this kind of SHR-2 setup?
Is there a workaround or method to expand my encrypted volume within this storage pool?
Any insights would be greatly appreciated! Thanks in advance.
I’ve not heard of a situation where there is one RAID under another. I think the inability to expand might be a limitation of the SHR-2 configuration. This is not an issue for SHR-1 and I know you can’t downgradee from 2 to 1. The only workaround I see is to create a brand-new encrypted volume. This sounds like a job for Synology Technical Support to get a definitive answer.
Hi SpiceRex: Thank you for the reply. What I meant with RAID array underlying the SHR was just referring to the way SHR works: It splits larger drives into smaller chunks, matching the smallest drive, then builds multiple RAID arrays on these smaller chunks to ensure redundancy.
Example 1: SHR-1 with 3x2TB and 2x1TB drives
First 1TB segment (all drives):
Uses 1TB from each drive (5 drives total).
5TB total, 1TB for parity → 4TB usable.
Remaining 1TB (from 2TB drives):
1TB from each 2TB drive (3 drives).
3TB total, 1TB for parity → 2TB usable.
Total usable: 6TB out of 8TB.
Example 2: SHR-2 with 3x2TB and 2x1TB drives
First 1TB segment (all drives):
Uses 1TB from each drive.
5TB total, 2TB for parity → 3TB usable.
Remaining 1TB (from 2TB drives):
1TB from each 2TB drive.
3TB total, 2TB for parity → 1TB usable.
Total usable: 4TB out of 8TB.
Anyhow, I guess no one has heard of an encrypted volume not being able to be extended if different size disks are in use. I would really like to avoid rebuilding the whole thing but guess there’s no other way to fix it. As I said, the unencrypted volume can be expanded to use the max available size of the SHR-2 storage pool. It’s just the encrypted one that can’t do it.
Hi dsm,
I’m familiar with how SHR works and how a storage pool can be split into unencrypted and encrypted volumes, thanks. I guess it wasn’t clear to me what you wanted to do. If you have unallocated disk space from your expansion it’s probably best to create a brand-new and bigger encrypted volume and migrate your older encrypted volume data over to there. Then you can remove (delete) that older encrypted volume to make it unallocated space that you can add to your existing unencrypted volume. Personally, I only keep 1 Tb of encrypted volume on 38Tb of storage space. Why? Because there are severe limitations imposed on encrypted volumes that don’t exist for their unencrypted counterpart. Rather, I opt for encrypted folders that will unmount when the NAS is rebooted. It keeps the folder out of the file station’s shared folder list and it is just as secure (short of having your NAS stolen) in my opinion.
I guess I will go back to encrypted folders rather than volume(s). The main reason I moved away from folders in favor of volume is the promised performance boost: “Full-Volume Encryption provides an up to 48% writing performance boost when compared with applying Shared Folder Encryption to all eligible data stored on a volume. Between the two modes, users now have efficient options to protect specific data or entire file systems against unauthorized access.” (Synology® raises the bar with DSM 7.2: Immutable storage, full-volume encryption, and more | Synology Inc.)
However, my inability to expand the encrypted volume truly sucks, and the additional work I will have to put in now to fix it is not worth any performance boost. I would ahve loved for someone to tell me that this issue is known and Syno is working on a solution. BTW, what other shortcomings are you referring to volume vs folder?
Well of course there is your problem of not being able to expand the volume easily. Volume encryption is a very CPU intensive process and can’t be undone (as far as I know). You need to plan it out and be plenty sure that what you want to do is a “long-term” solution. Even switching a folder from unencrypted to encrypted takes CPU time to do. People who encrypt their whole volume are playing with fire in my opinion. It is not out of the realm of possibility that a power outage or forced shutdown could cause glitching while writing to disk. Even unencrypted drives can sometimes (but not always) become inaccessible during a forced shutdown/power outage while writing to disk. In that scenario, encryption is just one more layer of complexity that can go sideways. I also don’t like that folders in an encrypted volume are always visible over smb. I regularly power-down my NAS and all encrypted folders will unmount. Anyone with unauthorized access through smb will not see those folders (as if they don’t exist). Faster write times and inaccessibility when drives are stolen are good, don’t get me wrong; but, if your drives are taken (stolen NAS) it’s a mixed blessing at best. These are just my personal preferences. Others may feel differently.
Do you still have any unallocated volume on your drives after adding the bigger drives? You can still do the workaround I mentioned previously.