addressed PM-review inputs

Author: AbhishekMallick-MS

articles/backup/backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md

@@ -9,15 +9,15 @@ ms.author: v-abhmallick
 
 # About agentless multi-disk crash-consistent backup for Azure VMs (preview)
 
-Azure Backup supports agentless VM backups by using multi-disk crash-consistent restore points (preview). The Enhanced VM backup policy now enables you to configure the consistency type of the backups (application-consistent restore points or crash-consistent restore points (preview) for Azure VMs. This feature also enables Azure VM backup to retry the backup operation with *crash-consistent snapshots* (for *supported VMs*) if the application-consistent snapshot fails. 
+Azure Backup supports agentless VM backups by using multi-disk [crash-consistent restore points](../virtual-machines/virtual-machines-create-restore-points.md) (preview). The [Enhanced VM backup policy](backup-azure-vms-enhanced-policy.md) now enables you to configure the consistency type of the backups (application-consistent restore points or crash-consistent restore points preview) for Azure VMs. This feature also enables Azure VM backup to retry the backup operation with *crash-consistent snapshots* (for *supported VMs*) if the application-consistent snapshot fails. 
 
 ## When do I choose crash-consistent backup over application-consistent backup?
 
 Choose to perform creah-consistent backup in the following scenarios:
 
 - If your workload is performance sensitive and can tolerate recovery from crash-consistent backups, crash-consistent backups help quiesce VM I/O for a shorter period during backup. Crash-consistent backup doesn't use Volume Shadow Copy Service, (VSS) (for Windows) or *fsfreeze* (for Linux) to avoid the associated quiescing delays. 
 
-- If you don't want to install the VM Agent or snapshot extension required for application-consistent or file-system-consistent snapshots in your Azure VM, use crash-consistent backups for an agentless backup solution.
+- If you don't want to install the [VM Agent](../virtual-machines/extensions/agent-windows.md) or [snapshot extension](../virtual-machines/extensions/vmsnapshot-windows.md) required for application-consistent or file-system-consistent snapshots in your Azure VM, use crash-consistent backups for an agentless backup solution.
 
 - If your operating system is not supported for application or file-system-consistent backup, use crash-consistent backups. Crash-consistent backup is operating system agnostic as it doesn't rely on the VM agent or snapshot extension.
 

articles/backup/backup-azure-vms-agentless-multi-disk-crash-consistent.md

@@ -13,6 +13,11 @@ This article describes how to configure backup for Azure VMs with agentless mult
 
 Azure Backup supports agentless VM backups by using multi-disk crash-consistent restore points (preview). The Enhanced VM backup policy now enables you to configure the consistency type of the backups (application-consistent restore points or crash-consistent restore points preview) for Azure VMs. This feature also enables Azure VM backup to retry the backup operation with *crash-consistent snapshots* (for *supported VMs*) if the application-consistent snapshot fails. 
 
+## Before you start
+
+Review the supported scenarios and limitations of agentless multi-disk crash-consistent backup. [Learn more](backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md).
+
+
 ## Configure backup for a new Azure VM with agentless multi-disk crash-consistent backup
 
 You need to set *crash-consistent backup* explicitly in this policy because *application/file-system-consistent backup* is the default setting.
@@ -62,7 +67,7 @@ Follow these steps:
 
 9. Select **Backup policy** to go to the **Change Backup Policy** blade.
 
-10. On the **Change Backup Policy**     blade, change the backup policy to the new one you created, verify that it has the Consistency type set to Crash consistent, and then  select **Change**.
+10. On the **Change Backup Policy** blade, change the backup policy to the new one you created, verify that it has the Consistency type set to Crash consistent, and then  select **Change**.
 
    A **Modifying protection** notification and a **Configure backup** job in your vault for the VM is triggered. Monitor the notification or job to check if the crash-consistent backup policy is added successfully.
 

articles/backup/backup-azure-vms-introduction.md

@@ -2,7 +2,7 @@
 title: About Azure VM backup
 description: In this article, learn how the Azure Backup service backs up Azure Virtual machines, and how to follow best practices.
 ms.topic: conceptual
-ms.date: 03/13/2024
+ms.date: 03/14/2024
 author: AbhishekMallick-MS
 ms.author: v-abhmallick
 ---
@@ -42,8 +42,7 @@ BEKs are also backed up. So, if the BEKs are lost, authorized users can restore
 
 Azure Backup takes snapshots according to the backup schedule.
 
->[!Note]
->If you have opted for application or file-system consistent backups, the VM needs to have a backup extension installed to coordinate for the snapshot process. For *agentless multi-disk crash-consistent* backups, the VM agent is not required for snapshots.
+If you have opted for application or file-system-consistent backups, the VM needs to have a backup extension installed to coordinate for the snapshot process. For [*agentless multi-disk crash-consistent* backups](backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md), the VM agent is not required for snapshots.
 
 - **Windows VMs:** For Windows VMs, the Backup service coordinates with VSS to take an app-consistent snapshot of the VM disks.  By default, Azure Backup takes a full VSS backup (it truncates the logs of application such as SQL Server at the time of backup to get application level consistent backup).  If you're using a SQL Server database on Azure VM backup, then you can modify the setting to take a VSS Copy backup (to preserve logs). For more information, see [this article](./backup-azure-vms-troubleshoot.md#troubleshoot-vm-snapshot-issues).
 
@@ -61,7 +60,8 @@ The following table explains the different types of snapshot consistency:
 --- | --- | --- | ---
 **Application-consistent** | This is the default setting in the VM backup policy. App-consistent backups capture memory content and pending I/O operations. App-consistent snapshots use a VSS writer (or pre/post scripts for Linux) to ensure the consistency of the app data before a backup occurs. | When you're recovering a VM with an app-consistent snapshot, the VM boots up. There's no data corruption or loss. The apps start in a consistent state. | Windows: All VSS writers succeeded<br/><br/> Linux: Pre/post scripts are configured and succeeded
 **File-system consistent** | This is the default setting in the VM backup policy. File-system consistent backups provide consistency by taking a snapshot of all files at the same time.<br/><br/> | When you're recovering a VM with a file-system consistent snapshot, the VM boots up. There's no data corruption or loss. Apps need to implement their own "fix-up" mechanism to make sure that restored data is consistent. | Windows: Some VSS writers failed <br/><br/> Linux: Default (if pre/post scripts aren't configured or failed)
-**Crash-consistent** | Crash-consistent snapshot is an opt-in setting in the VM backup policy. Azure Backup also takes crash-consistent backups if the VM is not running during backup and when application/file-consistent backups fail.   <br><br>   Only the data that already exists on the disk at the time of backup is captured and backed up. | Starts with the VM boot process followed by a disk check to fix corruption errors. Any in-memory data or write operations that weren't transferred to disk before the crash are lost. Apps implement their own data verification. For example, a database app can use its transaction log for verification. If the transaction log has entries that aren't in the database, the database software rolls transactions back until the data is consistent. | VM is in shutdown (stopped/ deallocated) state.
+**Crash-consistent** | Crash-consistent snapshot is an opt-in setting in the VM backup policy. Azure Backup also takes crash-consistent backups if the VM is not running during backup and when application/file-consistent backups fail.   <br><br>   Only the data that already exists on the disk at the time of the backup operation is captured and backed up; data in read/write host cache isn't captured. | Starts with the VM boot process followed by a disk check to fix corruption errors. Any in-memory data or write operations that weren't transferred to disk before the crash are lost. Apps implement their own data verification. For example, a database app can use its transaction log for verification. If the transaction log has entries that aren't in the database, the database software rolls transactions back until the data is consistent. | When you have opted for application/file-system backup and VM is in shutdown (stopped/ deallocated) state and when the snapshot is retried. <br><br> You have opted for agentless crash consistent backups
+
 
 >[!NOTE]
 > If the provisioning state is **succeeded**, Azure Backup takes file-system consistent backups. If the provisioning state is **unavailable** or **failed**, crash-consistent backups are taken. If the provisioning state is **creating** or **deleting**, that means Azure Backup is retrying the operations.

articles/backup/backup-support-matrix-iaas.md

@@ -2,7 +2,7 @@
 title: Support matrix for Azure VM backups
 description: Get a summary of support settings and limitations for backing up Azure VMs by using the Azure Backup service.
 ms.topic: conceptual
-ms.date: 03/13/2024
+ms.date: 03/14/2024
 ms.custom: references_regions 
 ms.reviewer: sharrai
 ms.service: backup
@@ -85,7 +85,7 @@ For Linux VM backups using the Linux Azure VM agent, Azure Backup supports the l
 - Agent-based VM backup doesn't support 32-bit operating systems.
 - Other bring-your-own Linux distributions might work as long as the [Azure VM agent for Linux](../virtual-machines/extensions/agent-linux.md) is available on the VM, and as long as Python is supported.
 - Agent-based VM backup doesn't support a proxy-configured Linux VM if it doesn't have Python version 2.7 or later installed.
-- Agentless crash-consistent backups are operating system agnostic and can be used to back up VMs whose operating system isn't supported for agent-based backups.
+- [Agentless crash-consistent backups](backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md) are operating system agnostic and can be used to back up VMs whose operating system isn't supported for agent-based backups.
 - Azure Backup doesn't support backing up Network File System (NFS) files that are mounted from storage, or from any other NFS server, to Linux or Windows machines. It backs up only disks that are locally attached to the VM.
 
 ## Support matrix for managed pre and post scripts for Linux databases

articles/backup/backup-support-matrix.md

@@ -2,7 +2,7 @@
 title: Azure Backup support matrix
 description: Provides a summary of support settings and limitations for the Azure Backup service.
 ms.topic: conceptual
-ms.date: 03/13/2024
+ms.date: 03/14/2024
 ms.custom: references_regions 
 ms.service: backup
 author: AbhishekMallick-MS
@@ -77,7 +77,7 @@ The following table lists the supported scenarios for backup of Linux machines:
 **Backup type** | **Linux (Azure endorsed)**
 --- | ---
 **Direct backup of on-premises machine that's running Linux** | Not supported. The MARS agent can be installed only on Windows machines.
-**Using agent extension to back up Azure VM that's running Linux** | Supports file-system, app-consistent backup (using [custom scripts](backup-azure-linux-app-consistent.md)) via an extension. Also supports [crash-consistent agentless backups](backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md).  <br/><br/> File-level recovery.<br/><br/> Restore by creating a VM from a recovery point or disk.
+**Using agent extension to back up Azure VM that's running Linux** or **agentless crash-consistent backup** | Supports file-system, app-consistent backup (using [custom scripts](backup-azure-linux-app-consistent.md)) via an extension. Also supports [crash-consistent agentless backups](backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md).  <br/><br/> File-level recovery.<br/><br/> Restore by creating a VM from a recovery point or disk.
 **Using DPM to back up on-premises machines running Linux** | File-consistent backup of Linux Guest VMs on Hyper-V and VMware.<br/><br/> VM restoration of Hyper-V and VMware Linux Guest VMs.
 **Using MABS to back up on-premises machines running Linux** | File-consistent backup of Linux Guest VMs on Hyper-V and VMware.<br/><br/> VM restoration of Hyper-V and VMware Linux guest VMs.
 **Using MABS or DPM to back up Linux Azure VMs** | Not supported.

includes/azure-vm-backup-process.md

@@ -9,8 +9,7 @@ ms.author: v-amallick
 1. For Azure VMs that are selected for backup, Azure Backup starts a backup job according to the backup schedule you specify.
 1. If you have opted for application or file-system consistent backups, the VM needs to have a backup extension installed to coordinate for the snapshot process.
 
-   >[!Note]
-   >If you have opted for crash-consistent backups, no agents are required in the VMs.
+   If you have opted for [crash-consistent backups](../../backup/backup-azure-vms-agentless-multi-disk-crash-consistent-overview.md), no agents are required in the VMs.
 
 1. During the first backup, a backup extension is installed on the VM if the VM is running.
     - For Windows VMs, the [VMSnapshot extension](../articles/virtual-machines/extensions/vmsnapshot-windows.md) is installed.

includes/backup-azure-agentless-multi-disk-crash-consistent-vm-backup-support-scenarios.md

@@ -15,5 +15,5 @@ Scenario | Supportability
 --- | ---
 **Region availability** | Supported in all Azure public regions.
 **Backup policy type** | Agentless crash-consistent backup is supported only with Enhanced Policy.
-**VM type and size** | - Supported for VM sizes that are premium storage capable (VM size that include "*s*" in their name) such as `DSv2`.   <br> - Trusted Launch VMs are supported. <br> - VMs with Ultra-disks, Premium v2 SSD, Ephemeral OS disks, Shared disks, and Write Accelerated disks aren't supported. <br> - Managed disks with paid bursting (striped disks) aren't supported.
+**VM type and size** | - Supported for [VM sizes](../../virtual-machines/vm-naming-conventions.md) that are premium storage capable (VM size that include "*s*" in their name) such as `DSv2`.   <br> - Trusted Launch VMs are supported. <br> - VMs with Ultra-disks, Premium v2 SSD, Ephemeral OS disks, Shared disks, and Write Accelerated disks aren't supported. <br> - Managed disks with paid bursting (striped disks) aren't supported.
 **Pre/post script** | Not supported for Linux VM backup.