acrofix

Author: Ankita Dutta

articles/site-recovery/concepts-azure-to-azure-high-churn-support.md

@@ -1,33 +1,34 @@
 ---
-title: Azure VM Disaster Recovery - High Churn support
-description: Describes how to protect your Azure VMs having high churning workloads.
+title: Azure virtual machine Disaster Recovery - High Churn support
+description: Describes how to protect your Azure virtual machines having high churning workloads.
 services: site-recovery
 author: ankitaduttaMSFT
 ms.service: site-recovery
 ms.topic: conceptual
-ms.date: 05/22/2024
+ms.date: 05/23/2024
 ms.author: ankitadutta
 ---
 
-# Azure VM Disaster Recovery - High Churn Support 
+# Azure virtual machine Disaster Recovery - High Churn Support 
 
-Azure Site Recovery supports churn (data change rate) up to 100 MB/s per VM. You will be able to protect your Azure VMs having high churning workloads (like databases) using the *High Churn* option in Azure Site Recovery which supports churn up to 100 MB/s per VM. You may be able to achieve better RPO performance for your high churning workloads. With the default Normal Churn option, you can [support churn only up to 54 MB/s per VM](./azure-to-azure-support-matrix.md#limits-and-data-change-rates). 
+Azure Site Recovery supports churn (data change rate) up to 100 MB/s per virtual machine. You'll  be able to protect your Azure virtual machines having high churning workloads (like databases) using the *High Churn* option in Azure Site Recovery, which supports churn up to 100 MB/s per virtual machine. You may be able to achieve better Recovery Point Objective performance for your high churning workloads. With the default Normal Churn option, you can [support churn only up to 54 MB/s per virtual machine](./azure-to-azure-support-matrix.md#limits-and-data-change-rates). 
 
 ## Limitations
 
-- Available only for DR of Azure VMs. 
-- Recommend VM SKUs with RAM of min 32GB. 
+- Available only for disaster recovery of Azure virtual machines. 
+- Virtual machine SKUs with RAM of min 32 GB are recommended. 
 - Source disks must be Managed Disks.
 
 > [!NOTE]
-> This feature is available in all [regions](./azure-to-azure-support-matrix.md#region-support) where Azure Site Recovery is supported and [Premium Blob storage](https://azure.microsoft.com/explore/global-infrastructure/products-by-region/?products=storage&regions=all&rar=true) accounts are available. When using High Churn with any other regions outside the supported regions, replication and/or reprotection may fail.
+> This feature is available in all [public regions](./azure-to-azure-support-matrix.md#region-support) where Azure Site Recovery is supported and premium block blobs are available. However, this feature is not yet available in any Government cloud regions.
+> When using High Churn with any other regions outside the supported regions, replication and/or reprotection may fail.
 
 ## Data change limits
 
 - These limits are based on our tests and don't cover all possible application I/O combinations. 
 - Actual results may vary based on your app I/O mix. 
 - There are two limits to consider:
-    - per disk data churn
+    - per disk data, churn
     - per virtual machine data churn. 
 - Limit per virtual machine data churn - 100 MB/s. 
 
@@ -38,29 +39,29 @@ The following table summarizes Site Recovery limits:
 |Standard or P10 or P15 |8 KB|2 MB/s|
 |Standard or P10 or P15|16 KB|4 MB/s|
 |Standard or P10 or P15|24 KB|6 MB/s|
-|Standard or P10 or P15|32 KB and above|10 MB/s|
+|Standard or P10 or P15|32 KB and later |10 MB/s|
 |P20|8 KB|10 MB/s|
 |P20 |16 KB|20 MB/s|
-|P20|24 KB and above|30 MB/s|
-|P30 and above|8 KB|20 MB/s|
-|P30 and above|16 KB|35 MB/s|
-|P30 and above|24 KB and above|50 MB/s|
+|P20|24 KB and later|30 MB/s|
+|P30 and later|8 KB|20 MB/s|
+|P30 and later|16 KB|35 MB/s|
+|P30 and later|24 KB and later|50 MB/s|
 
 ## How to enable High Churn support
 
 ### From Recovery Service Vault 
 
-1. Select source VMs on which you want to enable replication. To enable replication, follow the steps [here](./azure-to-azure-how-to-enable-replication.md).
+1. Select source virtual machines on which you want to enable replication. To enable replication, follow the steps [here](./azure-to-azure-how-to-enable-replication.md).
 
 2. Under **Replication Settings** > **Storage**, select **View/edit storage configuration**. The **Customize target settings** page opens.
 
    :::image type="Replication settings" source="media/concepts-azure-to-azure-high-churn-support/replication-settings-storages.png" alt-text="Screenshot of Replication settings storage." lightbox="media/concepts-azure-to-azure-high-churn-support/replication-settings-storages.png":::
 
 3. Under **Churn for the VM**, there are two options: 
 
-   - **Normal Churn** (this is the default option) - You can get up to 54 MB/s per VM. Select Normal Churn to use *Standard* storage accounts only for Cache Storage. Hence, Cache storage dropdown will list only *Standard* storage accounts. 
+   - **Normal Churn** (this is the default option) - You can get up to 54 MB/s per virtual machine. Select Normal Churn to use *Standard* storage accounts only for Cache Storage. Hence, Cache storage dropdown lists only *Standard* storage accounts. 
 
-   - **High Churn** - You can get up to 100 MB/s per VM. Select High Churn to use *Premium Block Blob* storage accounts only for Cache Storage. Hence, Cache storage dropdown will list only *Premium Block blob* storage accounts. 
+   - **High Churn** - You can get up to 100 MB/s per virtual machine. Select High Churn to use *Premium Block Blob* storage accounts only for Cache Storage. Hence, Cache storage dropdown lists only *Premium Block blob* storage accounts. 
 
       :::image type="Churn" source="media/concepts-azure-to-azure-high-churn-support/churns.png" alt-text="Screenshot of churn.":::
 
@@ -69,17 +70,17 @@ The following table summarizes Site Recovery limits:
 
    :::image type="High churn" source="media/concepts-azure-to-azure-high-churn-support/high-churn-new.png" alt-text="Screenshot of high-churn.":::
 
-   If you select multiple source VMs to configure Site Recovery and want to enable High Churn for all these VMs, select **High Churn** at the top level.
+   If you select multiple source virtual machines to configure Site Recovery and want to enable High Churn for all these virtual machines, select **High Churn** at the top level.
 
-5. After you select High Churn for the VM, you will see Premium Block Blob options only available for cache storage account. Select cache storage account and then select **Confirm Selection**. 
+5. After you select High Churn for the virtual machine, you'll  see Premium Block Blob options only available for cache storage account. Select cache storage account and then select **Confirm Selection**. 
 
    :::image type="Cache storage" source="media/concepts-azure-to-azure-high-churn-support/cache-storages.png" alt-text="Screenshot of Cache storage.":::
 
 6. Configure other settings and enable the replication. 
 
-### From Azure VM screen 
+### From Azure virtual machine screen 
 
-1. In the portal, go to **Virtual machines** and select the VM. 
+1. In the portal, go to **Virtual machines** and select the virtual machine. 
 
 2. On the left pane, under **Operations**, select **Disaster recovery**.
 
@@ -93,22 +94,22 @@ The following table summarizes Site Recovery limits:
 
    :::image type="Storage" source="media/concepts-azure-to-azure-high-churn-support/storage-show-details.png" alt-text="Screenshot of Storage show details.":::
 
-6. Under **Storage settings** > **Churn for the VM**, select **High Churn**. You will be able to use Premium Block Blob type of storage accounts only for cache storage. 
+6. Under **Storage settings** > **Churn for the VM**, select **High Churn**. You are able to use Premium Block Blob type of storage accounts only for cache storage. 
 
-     :::image type="High churn" source="media/concepts-azure-to-azure-high-churn-support/churn-for-vms.png" alt-text="Screenshot of Churn for VM.":::
+     :::image type="High churn" source="media/concepts-azure-to-azure-high-churn-support/churn-for-vms.png" alt-text="Screenshot of Churn for virtual machine.":::
 
 
 6. Select **Next: Review + Start replication**.
 
 >[!Note]
->- You can only enable High Churn only when you enable replication while configuring Azure Site Recovery on a VM.
->- If you want to enable High Churn support for VMs already protected by Azure Site Recovery, disable replication for those VMs and select **High Churn** while enabling replication again. Similarly, disable and enable replication again to switch back to **Normal Churn**.
+>- You can only enable High Churn only when you enable replication while configuring Azure Site Recovery on a virtual machine.
+>- If you want to enable High Churn support for virtual machines already protected by Azure Site Recovery, disable replication for those virtual machines and select **High Churn** while enabling replication again. Similarly, disable and enable replication again to switch back to **Normal Churn**.
 
 ## Cost Implications  
 
-- **High Churn** uses *Premium Block Blob* storage accounts which may have higher cost implications as compared to **Normal Churn** which uses *Standard* storage accounts. For more information, see [pricing](https://azure.microsoft.com/pricing/details/storage/blobs/).
-- For High churn VMs, more data changes may get replicated to target for **High churn** compared to **Normal churn**. This may lead to more network cost.
+- **High Churn** uses *Premium Block Blob* storage accounts, which may have higher cost implications as compared to **Normal Churn** which uses *Standard* storage accounts. For more information, see [pricing](https://azure.microsoft.com/pricing/details/storage/blobs/).
+- For High churn virtual machines, more data changes may get replicated to target for **High churn** compared to **Normal churn**. This may lead to more network cost.
 
 ## Next steps
 
-[Set up disaster recovery for Azure VMs](azure-to-azure-tutorial-enable-replication.md).
+[Set up disaster recovery for Azure virtual machines](azure-to-azure-tutorial-enable-replication.md).