Merge pull request #103190 from roygara/sharedDisks

TedA-M · web-flow · commit 3784c862fb78 · 2020-02-13T09:33:49.000-08:00
Shared disks
diff --git a/articles/virtual-machines/linux/disks-shared-enable.md b/articles/virtual-machines/linux/disks-shared-enable.md
@@ -0,0 +1,17 @@
+---
+title: Enable shared disks for Azure managed disks
+description: Configure an Azure managed disk with shared disks (preview) so that you can share it across multiple VMs
+author: roygara
+ms.service: virtual-machines-linux
+ms.topic: conceptual
+ms.date: 02/13/2020
+ms.author: rogarana
+ms.subservice: disks
+---
+
+# Enable shared disk
+
+This article covers how to enable the shared disks (preview) feature for Azure managed disks. Azure shared disks (preview) is a new feature for Azure managed disks that enables you to attach a managed disk to multiple virtual machines (VMs) simultaneously. Attaching a managed disk to multiple VMs allows you to either deploy new or migrate existing clustered applications to Azure. 
+
+If you are looking for conceptual information on managed disks that have shared disks enabled, refer to [Azure shared disks](disks-shared.md).
+[!INCLUDE [virtual-machines-enable-shared-disk](../../../includes/virtual-machines-enable-shared-disk.md)]
diff --git a/articles/virtual-machines/linux/disks-shared.md b/articles/virtual-machines/linux/disks-shared.md
@@ -0,0 +1,18 @@
+---
+title: Share an Azure managed disk across VMs (preview)
+description: Learn about sharing Azure managed disks across multiple VMs.
+author: roygara
+ms.service: virtual-machines-linux
+ms.topic: conceptual
+ms.date: 02/13/2020
+ms.author: rogarana
+ms.subservice: disks
+---
+
+# Azure shared disks
+
+[!INCLUDE [virtual-machines-disks-shared](../../../includes/virtual-machines-disks-shared.md)]
+
+## Next steps
+
+If you're interested in enabling and using shared disks for your managed disks, proceed to our article [Enable shared disk](disks-shared-enable.md)
diff --git a/articles/virtual-machines/linux/toc.yml b/articles/virtual-machines/linux/toc.yml
@@ -160,6 +160,8 @@
       href: disk-scalability-targets.md
     - name: Backup and disaster recovery for disks
       href: backup-and-disaster-recovery-for-azure-iaas-disks.md
+    - name: Shared disks
+      href: disks-shared.md
     - name: Ephemeral OS disks
       href: ephemeral-os-disks.md
   - name: Networking
@@ -553,6 +555,8 @@
     - name: Deploy disks with template
       displayName: Azure Resource Manager, ARM
       href: using-managed-disks-template-deployments.md
+    - name: Enable shared disks
+      href: disks-shared-enable.md
     - name: Upload a vhd to a disk - CLI
       href: disks-upload-vhd-to-managed-disk-cli.md
     - name: Resize a disk
diff --git a/articles/virtual-machines/windows/disks-shared-enable.md b/articles/virtual-machines/windows/disks-shared-enable.md
@@ -0,0 +1,17 @@
+---
+title: Enable shared disks for Azure managed disks
+description: Configure an Azure managed disk with shared disks (preview) so that you can share it across multiple VMs
+author: roygara
+ms.service: virtual-machines-windows
+ms.topic: conceptual
+ms.date: 02/13/2020
+ms.author: rogarana
+ms.subservice: disks
+---
+
+# Enable shared disk
+
+This article covers how to enable the shared disks (preview) feature for Azure managed disks. Azure shared disks (preview) is a new feature for Azure managed disks that enables you to attach a managed disk to multiple virtual machines (VMs) simultaneously. Attaching a managed disk to multiple VMs allows you to either deploy new or migrate existing clustered applications to Azure. 
+
+If you are looking for conceptual information on managed disks that have shared disks enabled, refer to [Azure shared disks](disks-shared.md).
+[!INCLUDE [virtual-machines-enable-shared-disk](../../../includes/virtual-machines-enable-shared-disk.md)]
diff --git a/articles/virtual-machines/windows/disks-shared.md b/articles/virtual-machines/windows/disks-shared.md
@@ -0,0 +1,18 @@
+---
+title: Sharing an Azure managed disk across VMs (preview)
+description: Learn about sharing Azure managed disks across multiple VMs.
+author: roygara
+ms.service: virtual-machines-windows
+ms.topic: conceptual
+ms.date: 02/13/2020
+ms.author: rogarana
+ms.subservice: disks
+---
+
+# Azure shared disks
+
+[!INCLUDE [virtual-machines-disks-shared](../../../includes/virtual-machines-disks-shared.md)]
+
+## Next steps
+
+If you're interested in enabling and using shared disks for your managed disks, proceed to our article [Azure shared disks](disks-shared.md).
diff --git a/articles/virtual-machines/windows/toc.yml b/articles/virtual-machines/windows/toc.yml
@@ -241,7 +241,9 @@
     - name: Scalability targets for disks
       href: disk-scalability-targets.md
     - name: Backup and disaster recovery for disks
-      href: backup-and-disaster-recovery-for-azure-iaas-disks.md   
+      href: backup-and-disaster-recovery-for-azure-iaas-disks.md
+    - name: Shared disks
+      href: disks-shared.md
     - name: Ephemeral OS disks
       href: ephemeral-os-disks.md
   - name: Networking
@@ -547,6 +549,8 @@
       href: detach-disk.md
     - name: Deploy disks with template
       href: using-managed-disks-template-deployments.md
+    - name: Enable shared disks
+      href: disks-shared-enable.md
     - name: Upload a vhd to a disk - PowerShell
       href: disks-upload-vhd-to-managed-disk-powershell.md
     - name: Resize a disk
diff --git a/includes/media/virtual-machines-disks-shared-disks/shared-disk-updated-machine-learning-trainer-model.png b/includes/media/virtual-machines-disks-shared-disks/shared-disk-updated-machine-learning-trainer-model.png
diff --git a/includes/media/virtual-machines-disks-shared-disks/shared-disk-updated-two-node-cluster-diagram.png b/includes/media/virtual-machines-disks-shared-disks/shared-disk-updated-two-node-cluster-diagram.png
diff --git a/includes/virtual-machines-disks-shared-limitations.md b/includes/virtual-machines-disks-shared-limitations.md
@@ -0,0 +1,24 @@
+---
+ title: include file
+ description: include file
+ services: virtual-machines
+ author: roygara
+ ms.service: virtual-machines
+ ms.topic: include
+ ms.date: 02/13/2020
+ ms.author: rogarana
+ ms.custom: include file
+---
+
+While in preview, managed disks that have shared disks enabled are subject to the following limitations:
+
+- Currently only available with premium SSDs.
+- Currently only supported in the West Central US region.
+- All virtual machines sharing a disk must be deployed in the same [proximity placement groups](../articles/virtual-machines/windows/proximity-placement-groups.md).
+- Can only be enabled on data disks, not OS disks.
+- Only basic disks can be used with some versions of Windows Server Failover Cluster, for details see [Failover clustering hardware requirements and storage options](https://docs.microsoft.com/windows-server/failover-clustering/clustering-requirements).
+- ReadOnly host caching is not available for premium SSDs with `maxShares>1`.
+- Availability sets and virtual machine scale sets can only be used with `FaultDomainCount` set to 1.
+- Azure Backup and Azure Site Recovery support is not yet available.
+
+If you're interested in trying shared disks then [sign up for our preview](https://aka.ms/shareddisksignup).
diff --git a/includes/virtual-machines-disks-shared-sizes.md b/includes/virtual-machines-disks-shared-sizes.md
@@ -0,0 +1,28 @@
+---
+ title: include file
+ description: include file
+ services: virtual-machines
+ author: roygara
+ ms.service: virtual-machines
+ ms.topic: include
+ ms.date: 02/13/2020
+ ms.author: rogarana
+ ms.custom: include file
+---
+
+For now, only premium SSDs can enable shared disks. The disk sizes that support this feature are P15 and greater. Different disk sizes may have a different `maxShares` limit, which you cannot exceed when setting the `maxShares` value.
+
+For each disk, you can define a `maxShares` value that represents the maximum number of nodes that can simultaneously share the disk. For example, if you plan to set up a 2-node failover cluster, you would set `maxShares=2`. The maximum value is an upper bound. Nodes can join or leave the cluster (mount or unmount the disk) as long as the number of nodes is lower than the specified `maxShares` value.
+
+> [!NOTE]
+> The `maxShares` value can only be set or edited when the disk is detached from all nodes.
+
+The following table illustrates the allowed maximum values for `maxShares` by disk size:
+
+|Disk sizes  |maxShares limit  |
+|---------|---------|
+|P15, P20     |2         |
+|P30, P40, P50     |5         |
+|P60, P70, P80     |10         |
+
+The IOPS and bandwidth limits for a disk are not affected by the `maxShares` value. For example, the max IOPS of a P15 disk are 1100 whether maxShares = 1 or maxShares > 1.
diff --git a/includes/virtual-machines-disks-shared.md b/includes/virtual-machines-disks-shared.md
@@ -0,0 +1,73 @@
+---
+ title: include file
+ description: include file
+ services: virtual-machines
+ author: roygara
+ ms.service: virtual-machines
+ ms.topic: include
+ ms.date: 02/13/2020
+ ms.author: rogarana
+ ms.custom: include file
+---
+
+Azure shared disks (preview) is a new feature for Azure managed disks that enables attaching an Azure managed disk to multiple virtual machines (VMs) simultaneously. Attaching a managed disk to multiple VMs allows you to either deploy new or migrate existing clustered applications to Azure.
+
+## How it works
+
+VMs in the cluster can read or write to your attached disk based on the reservation chosen by the clustered application using [SCSI Persistent Reservations](https://www.t10.org/members/w_spc3.htm) (SCSI PR). SCSI PR is a well-known industry standard leveraged by applications running on Storage Area Network (SAN) on-premises. Enabling SCSI PR on a managed disk allows you to migrate these applications to Azure as-is.
+
+Managed disks with shared disks enabled offer shared block storage that can be accessed by multiple VMs, this is exposed as logical unit numbers (LUNs). LUNs are then presented to an initiator (VM) from a target (disk). These LUNs look like direct-attached-storage (DAS) or a local drive to the VM.
+
+Managed disks with shared disks enabled do not natively offer a fully-managed file system that can be accessed using SMB/NFS. You will need to use a cluster manager, like Windows Server Failover Cluster (WSFC) or Pacemaker, that handles cluster node communication as well as write locking.
+
+## Limitations
+
+[!INCLUDE [virtual-machines-disks-shared-limitations](virtual-machines-disks-shared-limitations.md)]
+
+## Disk sizes
+
+[!INCLUDE [virtual-machines-disks-shared-sizes](virtual-machines-disks-shared-sizes.md)]
+
+## Sample workloads
+
+### Windows
+
+Most Windows-based clustering build on WSFC, which handles all core infrastructure for cluster node communication, allowing your applications to take advantage of parallel access patterns. WSFC enables both CSV and non-CSV-based options depending on your version of Windows Server. For details, refer to [Create a failover cluster](https://docs.microsoft.com/windows-server/failover-clustering/create-failover-cluster).
+
+Some popular applications running on WSFC include:
+
+- SQL Server Failover Cluster Instances (FCI)
+- Scale-out File Server (SoFS)
+- File Server for General Use (IW workload)
+- Remote Desktop Server User Profile Disk (RDS UPD)
+- SAP ASCS/SCS
+
+### Linux
+
+Linux clusters can leverage cluster managers such as [Pacemaker](https://wiki.clusterlabs.org/wiki/Pacemaker). Pacemaker builds on [Corosync](http://corosync.github.io/corosync/), enabling cluster communications for applications deployed in highly available environments. Some common clustered filesystems include [ocfs2](https://oss.oracle.com/projects/ocfs2/) and [gfs2](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/global_file_system_2/ch-overview-gfs2). You can manipulate reservations and registrations using utilities such as [fence_scsi](http://manpages.ubuntu.com/manpages/eoan/man8/fence_scsi.8.html) and [sg_persist](https://linux.die.net/man/8/sg_persist).
+
+## Persistent Reservation flow
+
+The following diagram illustrates a sample 2-node clustered database application that leverages SCSI PR to enable failover from one node to the other.
+
+![shared-disk-updated-two-node-cluster-diagram.png](media/virtual-machines-disks-shared-disks/shared-disk-updated-two-node-cluster-diagram.png)
+
+The flow is as follows:
+
+1. The clustered application running on both Azure VM1 and VM2 registers its intent to read or write to the disk.
+1. The application instance on VM1 then takes exclusive reservation to write to the disk.
+1. This reservation is enforced on your Azure disk and the database can now exclusively write to the disk. Any writes from the application instance on VM2 will not succeed.
+1. If the application instance on VM1 goes down, the instance on VM2 can now initiate a database failover and take-over of the disk.
+1. This reservation is now enforced on the Azure disk and the disk will no longer accept writes from VM1. It will only accept writes from VM2.
+1. The clustered application can complete the database failover and serve requests from VM2.
+
+The following diagram illustrates another common clustered workload consisting of multiple nodes reading data from the disk for running parallel processes, such as training of machine learning models.
+
+![shared-disk-updated-machine-learning-trainer-model.png](media/virtual-machines-disks-shared-disks/shared-disk-updated-machine-learning-trainer-model.png)
+
+The flow is as follows:
+
+1. The clustered application running on all VMs registers the intent to read or write to the disk.
+1. The application instance on VM1 takes an exclusive reservation to write to the disk while opening up reads to the disk from other VMs.
+1. This reservation is enforced on your Azure disk.
+1. All nodes in the cluster can now read from the disk. Only one node writes back results to the disk, on behalf of all nodes in the cluster.
diff --git a/includes/virtual-machines-enable-shared-disk.md b/includes/virtual-machines-enable-shared-disk.md
@@ -0,0 +1,141 @@
+---
+ title: include file
+ description: include file
+ services: virtual-machines
+ author: roygara
+ ms.service: virtual-machines
+ ms.topic: include
+ ms.date: 02/13/2020
+ ms.author: rogarana
+ ms.custom: include file
+---
+
+## Limitations
+
+[!INCLUDE [virtual-machines-disks-shared-limitations](virtual-machines-disks-shared-limitations.md)]
+
+## Disk sizes
+
+[!INCLUDE [virtual-machines-disks-shared-sizes](virtual-machines-disks-shared-sizes.md)]
+
+## Deploy an Azure shared disk
+
+To deploy a managed disk with the shared disk feature enabled, use the new property `maxShares` and define a value `>1`. This makes the disk shareable across multiple VMs.
+
+> [!IMPORTANT]
+> The value of `maxShares` can only be set or changed when a disk is unmounted from all VMs. See the [Disk sizes](#disk-sizes) for the allowed values for `maxShares`.
+
+Before using the following template, replace `[parameters('dataDiskName')]`, `[resourceGroup().location]`, `[parameters('dataDiskSizeGB')]`, and `[parameters('maxShares')]` with your own values.
+
+```json
+{ 
+  "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
+  "contentVersion": "1.0.0.0",
+  "parameters": {
+    "dataDiskName": {
+      "type": "string",
+      "defaultValue": "mySharedDisk"
+    },
+    "dataDiskSizeGB": {
+      "type": "int",
+      "defaultValue": 1024
+    },
+    "maxShares": {
+      "type": "int",
+      "defaultValue": 2
+    }
+  },
+  "resources": [
+    {
+      "type": "Microsoft.Compute/disks",
+      "name": "[parameters('dataDiskName')]",
+      "location": "[resourceGroup().location]",
+      "apiVersion": "2019-07-01",
+      "sku": {
+        "name": "Premium_LRS"
+      },
+      "properties": {
+        "creationData": {
+          "createOption": "Empty"
+        },
+        "diskSizeGB": "[parameters('dataDiskSizeGB')]",
+        "maxShares": "[parameters('maxShares')]"
+      }
+    }
+  ] 
+}
+```
+
+### Using Azure shared disks with your VMs
+
+Once you've deployed a shared disk with `maxShares>1`, you can mount the disk to one or more of your VMs.
+
+> [!IMPORTANT]
+> All VMs sharing a disk must be deployed in the same [proximity placement group](../articles/virtual-machines/windows/proximity-placement-groups.md).
+
+```azurepowershell-interactive
+
+$resourceGroup = "myResourceGroup"
+$location = "WestCentralUS"
+$ppgName = "myPPG"
+$ppg = New-AzProximityPlacementGroup `
+   -Location $location `
+   -Name $ppgName `
+   -ResourceGroupName $resourceGroup `
+   -ProximityPlacementGroupType Standard
+
+$vm = New-AzVm -ResourceGroupName $resourceGroup -Name "myVM" -Location $location -VirtualNetworkName "myVnet" -SubnetName "mySubnet" -SecurityGroupName "myNetworkSecurityGroup" -PublicIpAddressName "myPublicIpAddress" -ProximityPlacementGroup $ppg.Id
+
+$dataDisk = Get-AzDisk -ResourceGroupName $resourceGroup -DiskName "mySharedDisk"
+
+$vm = Add-AzVMDataDisk -VM $vm -Name "mySharedDisk" -CreateOption Attach -ManagedDiskId $dataDisk.Id -Lun 0
+
+update-AzVm -VM $vm -ResourceGroupName $resourceGroup
+```
+
+## Supported SCSI PR commands
+
+Once you've mounted the shared disk to your VMs in your cluster, you can establish quorum and read/write to the disk using SCSI PR. The following PR commands are available when using Azure shared disks:
+
+To interact with the disk, start with the persistent-reservation-action list:
+
+```
+PR_REGISTER_KEY 
+
+PR_REGISTER_AND_IGNORE 
+
+PR_GET_CONFIGURATION 
+
+PR_RESERVE 
+
+PR_PREEMPT_RESERVATION 
+
+PR_CLEAR_RESERVATION 
+
+PR_RELEASE_RESERVATION 
+```
+
+When using PR_RESERVE, PR_PREEMPT_RESERVATION, or  PR_RELEASE_RESERVATION, provide one of the following persistent-reservation-type:
+
+```
+PR_NONE 
+
+PR_WRITE_EXCLUSIVE 
+
+PR_EXCLUSIVE_ACCESS 
+
+PR_WRITE_EXCLUSIVE_REGISTRANTS_ONLY 
+
+PR_EXCLUSIVE_ACCESS_REGISTRANTS_ONLY 
+
+PR_WRITE_EXCLUSIVE_ALL_REGISTRANTS 
+
+PR_EXCLUSIVE_ACCESS_ALL_REGISTRANTS 
+```
+
+You also need to provide a persistent-reservation-key when using PR_RESERVE, PR_REGISTER_AND_IGNORE, PR_REGISTER_KEY, PR_PREEMPT_RESERVATION, PR_CLEAR_RESERVATION, or PR_RELEASE-RESERVATION.
+
+
+## Next steps
+
+If you're interested in trying shared disks, [sign up for our preview](https://aka.ms/shareddisksignup).
diff --git a/includes/virtual-machines-faq-for-disks.md b/includes/virtual-machines-faq-for-disks.md
