Creating a RAID-5 using Storage Spaces in Windows 11

Question

Hi, first time posting here. I tried to search but I couldn't find and I don't know if this is something very specific or not.

I want to try the new Storage Spaces in Windows 11. Some years ago I bought an external enclosure with 5-bay for hard drives and also provide RAID 5 functionality out-of-the-box. It works pretty good and no issue. This time I want to mount another RAID 5 but using the built-in Storage Spaces available in Windows 11.

My previous RAID5 was using 5 HDD with 8 TB each, so the total available was 32 TB (29.1 in reality).

My new RAID5 will be with 6 HDD with 8 TB each, that's suppose to be 40 TB from what I understand (or ~35 GB in reality).

I started creating an Storage Pool in Windows 11 and then associated all the 6 storage drives

Then my options from what I understand are

• Resiliency type: Parity
• Total pool capacity: 43.6 TB
• Available pool capacity: 43.6 TB
• Size (maximum): 29.0 TB
• Including resiliency: 43.5 TB

Supposedly the Size is auto-calculated depending of Total pool and Resiliency type, but my question is why is so low? The size will be less than my current RAID5 with 5 disks, it should be more with 6 disks.

If I change the size to the correct value I get

• Size (maximum): 36.3 TB
• Including resiliency: 54.4 TB

I don't know if I am doing something wrong or I don't fully understand this. If I create the Storage with the default options effectively it creates a new Disk but with less size than my current Storage. Any help will be appreciated. Thanks in advance.

Answer 1

Same here.

3x8TB drives have around 14,5TB with parity in Storages Spaces.

Having 4x8TB, is can only use 19,3TB instead of around 21,4TB expected capacity.

When I use the old disk management console and create a Raid5 configuration, I get the expected 21,4TB.

So it seems, that Storage Spaces has some hidden overhead maybe due to the rotating parity implementation.

I am very anoyed, to loose 2TB of data into the void.

Currently I still have no solution. Maybe it is possible to change the rotation parity to a normal one and get the data back? If that is really the issue. Only Microsoft knows :-(

Answer 2

I got it. I found the 2 missing TB.

When having 4 drives, you also have to set the column size to 4.

Storage Spaces seems to use column size of 3 by default, no matter how many disks you use. The downside seems to be, that with increasing column size, the performance decreases.

New-VirtualDisk -FriendlyName "VD_24TB" -StoragePoolFriendlyName "Pool_24TB" -UseMaximumSize -ResiliencySettingName Parity -Interleave 262144-NumberOfColumns 4