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I have 2 disks (1TB + 1.5TB) in a Storage Space. Free space shows up as 2.27TB.

I create a new Virtual disk with Simple layout (no redundancy). Maximum size for the virtual disks stops at 1.82TB (seems to be the 2TB drive limiting). I can then also create a second virtual disk of the remaining size.

Why can't I create a 2.27TB disk, isn't that possible?

  • 1
    Are the disks in a RAID configuration? – Robert Harvey Sep 25 '13 at 20:25
  • No Raid, SATA-drives, empty disks. Using the Server Manager - File and Storage Services - Volumes - Storage Pools guide. – Sam Sep 26 '13 at 8:15
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I found a workaround: Add disk1 to the pool, and create a fixed Virtual Disk with a NTFS Volume (sized to the max of disk1). Then I add disk2 to the storage pool and extend the Virtual Disk, and extend the NTFS Volume. Then I can use all available storage from disk1 & disk2 in one NTFS volume.

I have to do it in two steps.

Can anyone confirm this behavior, or explain it to me?

  • 1
    With some RAID controllers, and some software RAID systems (like Storage Pools), you can create a RAID from two different size disks, it ignores the extra on the larger disk. SOME systems let you create another virtual disk (non-raid) out of the leftover. Your answer sounds like a JBOD array. Be aware that there is no redundancy in this setup. If you put production servers into a setup like this, you need to plan for downtime, and plan to minimize it. You need good backups either way, but in JBOD you will also need spare parts on-hand to replace the drive then restore to it. – Xalorous Oct 6 '16 at 12:52
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Not sure why, but the UI seems to default to mirror striping for disks of equal size in Windows Server 2012 R2. In my case, 4TB + 4TB + 2TB (10TB total) created a virtual disk of 6TB, i.e. it seems two 4TB disks were used in RAID 1.

To solve this, you can use the New-VirtualDisk PowerShell command, using the following parameters:

// this will create a "Simple" JBOD virtual disk over the entire storage pool
New-VirtualDisk 
  -FriendlyName Your_new_vdisk_name 
  -StoragePoolFriendlyName Your_existing_pool_name
  -ResiliencySettingName Simple
  -NumberOfColumns 1
  -UseMaximumSize

Make sure you remove any previous virtual disks from the pool. Also, you will need to refresh the Storage Pools page to see these changed after running the command.

  • 1
    Before using JBOD, be aware that it has no redundancy. You are accepting the risk of downtime when a drive fails. This risk makes JBOD unsuitable for any system with uptime SLAs. And as usual, keep in mind that RAID is redundant hardware, not a backup, and backups are important for both RAID and non-redundant arrays. – Xalorous Oct 6 '16 at 12:55

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