Merge pull request #229220 from roygara/updateEph

Updating managed disk OS disk size limit

Author: prmerger-automator[bot]

articles/virtual-machines/ephemeral-os-disks.md

@@ -30,7 +30,7 @@ Key differences between persistent and ephemeral OS disks:
 
 |   | Persistent OS Disk | Ephemeral OS Disk |
 |---|---|---|
-| **Size limit for OS disk** | 2 TiB | Cache size or temp size for the VM size or 2040 GiB, whichever is smaller. For the **cache or temp size in GiB**, see [DS](sizes-general.md), [ES](sizes-memory.md), [M](sizes-memory.md), [FS](sizes-compute.md), and [GS](sizes-previous-gen.md#gs-series) |
+| **Size limit for OS disk** | 4* TiB | Cache size or temp size for the VM size or 2040 GiB, whichever is smaller. For the **cache or temp size in GiB**, see [DS](sizes-general.md), [ES](sizes-memory.md), [M](sizes-memory.md), [FS](sizes-compute.md), and [GS](sizes-previous-gen.md#gs-series) |
 | **VM sizes supported** | All | VM sizes that support Premium storage such as DSv1, DSv2, DSv3, Esv3, Fs, FsV2, GS, M, Mdsv2, Bs, Dav4, Eav4 |
 | **Disk type support**| Managed and unmanaged OS disk| Managed OS disk only|
 | **Region support**| All regions| All regions|
@@ -45,6 +45,8 @@ Key differences between persistent and ephemeral OS disks:
 | **Maintenance of VM/VMSS using [healing](understand-vm-reboots.md#unexpected-downtime)** | OS disk data is preserved | OS disk data is not preserved  | 
 | **Maintenance of VM/VMSS using [Live Migration](maintenance-and-updates.md#live-migration)** | OS disk data is preserved | OS disk data is preserved  | 
 
+\* 4 TiB is the maximum supported OS disk size for managed (persistent) disks. However, many OS disks are partitioned with master boot record (MBR) by default and because of this are limited to 2 TiB. For details, see [OS disk](managed-disks-overview.md#os-disk).
+
 ## Placement options for Ephemeral OS disks
 Ephemeral OS disk can be stored either on VM's OS cache disk or VM's temp/resource disk. 
 [DiffDiskPlacement](/rest/api/compute/virtualmachines/list#diffdiskplacement) is the new property that can be used to specify where you want to place the Ephemeral OS disk. With this feature, when a Windows VM is provisioned, we configure the pagefile to be located on the OS Disk.