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Creating a RAID-5 using Storage Spaces in Windows 11

Anonymous
2023-10-18T14:05:41+00:00

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.

Windows for home | Windows 11 | Files, folders, and storage

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  1. Anonymous
    2024-01-03T23:56:39+00:00

    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

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  2. Anonymous
    2023-10-18T15:13:57+00:00

    Hi Horace

    I already know how RAID-5 works, in fact, that's the reason why I'm asking. Because like I mentioned in the beginning, with 6 disk with 8 TB each, RAID-5 should be 40 TB, and even considering that the disk aren't 8TB exactly, is not even near to 29.0 TB as showed in the screenshot. It should be near 33~35 in reality

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  3. Anonymous
    2024-01-03T23:26:35+00:00

    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 :-(

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  4. Anonymous
    2023-10-18T16:13:40+00:00

    Exactly... with 6 disk, the parity should only be 1 disk and the available capacity should be the other 5 disks, the math doesn't sum up correctly and that's why I'm confused...

    6 Disks * 8 TB = 48 TB

    RAID5 (6-1) * 8 TB = 40 TB

    considering that the disks are not really 8 TB, using 7.3 TB as the real capacity the math still doesn't sum up

    6 Disks * 7.3 TB = 43.8 TB (equivalent to the total pool capacity)

    RAID5 (6-1) * 7.3 TB = 36.5 TB

    but why according to the storage space is 29.0 !?? Is a lot less

    2 people found this answer helpful.
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  5. Anonymous
    2023-10-18T17:05:19+00:00

    My issue is not about that... I already know that when a disk says X TB it isn't really X TB and in really is even a lot less...

    My issue is about the Size (maximum) value... If I use the 29.0 TB it seems pretty low for 6 disk RAID5. The textbox can be modified to use a higher value but I don't know if that will cause issues. I can even use the maximum Total pool capacity as size and but according to the "including resiliency" I overpass considerably to the total pool.

    Is there something I'm doing wrong? Will I have to settle for only having 29 for 6 disks or can I increase the value and ignore the warning? It would be a problem if I put the 36 TB that is more correct for 6 disk RAID5 ?

    Thanks in advance

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