Q: Can the 2012 R2 Storage Space Write-back cache size be set via Server Manager in 2012 R2?

A: It isn't possible to set a write-back cache custom size by using Server Manager in Windows Server 2012 R2. By default, if you create a virtual disk using Server Manager, it will create a 1GB write-back cache if sufficient space exists on solid-state disk (SSD) storage in the pool.

If you want to customize the write-back cache size, use the Windows PowerShell cmdlets and the -WriteCacheSize parameter, for example:

New-VirtualDisk -StoragePoolFriendlyName "My Storage Pool" -FriendlyName TieredSpace -StorageTiers @($ssd_tier, $hdd_tier) -StorageTierSizes @(50GB, 300GB) -ResiliencySettingName Mirror -WriteCacheSize 2GB  

Note: After a virtual disk is created, its WriteCacheSize can't be modified.