ASC15 changes

Author: ronhogue

articles/hpc-cache/configuration.md

@@ -76,7 +76,7 @@ Consider using a test cache to check and refine your DNS setup before you use it
 
 ### Refresh storage target DNS
 
-If your DNS server updates IP addresses, the associated NFS storage targets will become temporarily unavailable. Read how to update your custom DNS system IP addresses in [View and manage storage targets](manage-storage-targets.md#update-ip-address-specific-configurations-only).
+If your DNS server updates IP addresses, the associated NFS storage targets will become temporarily unavailable. Read how to update your custom DNS system IP addresses in [View and manage storage targets](manage-storage-targets.md#update-ip-address).
 
 ## View snapshots for blob storage targets
 

articles/hpc-cache/hpc-cache-create.md

@@ -4,7 +4,7 @@ description: How to create an Azure HPC Cache instance
 author: ronhogue
 ms.service: hpc-cache
 ms.topic: how-to
-ms.date: 01/19/2022
+ms.date: 01/25/2022
 ms.author: rohogue 
 ms.custom: devx-track-azurepowershell
 ---
@@ -30,6 +30,9 @@ In **Project Details**, select the subscription and resource group that will hos
 In **Service Details**, set the cache name and these other attributes:
 
 * Location - Select one of the [supported regions](hpc-cache-overview.md#region-availability).
+
+  If that region supports [availability zones](../../availability-zones/az-overview), select the zone that will host your cache resources. Azure HPC Cache is a zonal service.
+
 * Virtual network - You can select an existing one or create a new virtual network.
 * Subnet - Choose or create a subnet with at least 64 IP addresses (/24). This subnet must be used only for this Azure HPC Cache instance.
 

articles/hpc-cache/manage-storage-targets.md

@@ -4,7 +4,7 @@ description: How to suspend, remove, force delete, and flush Azure HPC Cache sto
 author: ronhogue
 ms.service: hpc-cache
 ms.topic: how-to
-ms.date: 01/06/2022
+ms.date: 01/25/2022
 ms.author: rohogue
 ---
 
@@ -31,12 +31,12 @@ These options are available:
 
 * **Flush** - Write all cached changes to the back-end storage
 * **Suspend** - Temporarily stop the storage target from serving requests
-* **Resume** - Put a suspended storage target back into service
+* **Refresh DNS** - Update the storage target IP address from a custom DNS server or from an Azure Storage private endpoint
+* **Invalidate** - Discards cached files from this storage target (**might cause data loss**)
 * **Force remove** - Delete a storage target, skipping some safety steps (**Force remove can cause data loss**)
+* **Resume** - Put a suspended storage target back into service
 * **Delete** - Permanently remove a storage target
 
-Some storage targets also have a **Refresh DNS** option on this menu, which updates the storage target IP address from a custom DNS server or from an Azure Storage private endpoint.
-
 Read the rest of this article for more detail about these options.
 
 ### Write cached files to the storage target
@@ -59,6 +59,40 @@ The suspend feature disables client access to a storage target, but doesn't perm
 
 Use **Resume** to un-suspend a storage target.
 
+### Update IP address
+
+In some situations, you might need to update your storage target's IP address. This can happen in two scenarios:
+
+* Your cache uses a custom DNS system instead of the default setup, and the network infrastructure has changed.
+
+* Your storage target uses a private endpoint to access Azure Blob or NFS-mounted blob storage, and you have updated the endpoint's configuration. (You should suspend storage targets before modifying their private endpoints, as described in the [prerequisites article](hpc-cache-prerequisites.md#work-with-private-endpoints).)
+
+With a custom DNS system, it's possible for your NFS storage target's IP address to change because of back-end DNS changes. If your DNS server changes the back-end storage system's IP address, Azure HPC Cache can lose access to the storage system. Ideally, you should work with the manager of your cache's custom DNS system to plan for any updates, because these changes make storage unavailable.
+
+If you use a private endpoint for secure storage access, the endpoint's IP addresses can change if you modify its configuration. If you need to change your private endpoint configuration, you should suspend the storage target (or targets) that use the endpoint, then refresh their IP addresses when you re-activate them. Read [Work with private endpoints](hpc-cache-prerequisites.md#work-with-private-endpoints) for additional information.
+
+To update a storage target's IP address, use the **Refresh DNS** option. The cache queries the custom DNS server or private endpoint for a new IP address.
+
+If successful, the update should take less than two minutes. You can only refresh one storage target at a time; wait for the previous operation to complete before trying another.
+
+> [!NOTE]
+> The "Refresh DNS" option is disabled for NFS storage targets that use IP addresses instead of a DNS hostname.
+
+### Invalidate cache contents for a storage target
+
+The **Invalidate** option tells the HPC Cache to mark all cached files from this storage target as out of date. The next time a client requests these files, they will be fetched from the back-end storage system.
+
+You could use this option if you update files on the back-end storage system directly and want to make those changes immediately available to the clients connected to the HPC Cache.
+
+> [!NOTE]
+> If you use ***write caching*** for this storage target, invalidating its cache can possibly cause data loss. If a client has written a change to the cache, but it has not yet been copied to the back-end storage system, that change will be discarded.
+
+The amount of time between when a client write is saved to the cache and the time that file is written to the long-term storage system is variable. There's no way for HPC Cache to determine whether or not one particular file has been written back to its storage system before invalidating the cache.
+
+If you need to make sure all cached changes are saved to the back-end storage system, use a **Flush** command.
+
+Learn more about write caching and file write-back delay in [Understand cache usage models](cache-usage-models.md).
+
 ### Force remove a storage target
 
 > [!NOTE]
@@ -105,23 +139,6 @@ $ az hpc-cache storage-target remove --resource-group cache-rg --cache-name doc-
 
 ---
 
-### Update IP address (specific configurations only)
-
-In some situations, you might need to update your storage target's IP address. This can happen in two scenarios:
-
-* Your cache uses a custom DNS system instead of the default setup, and the network infrastructure has changed.
-
-* Your storage target uses a private endpoint to access Azure Blob or NFS-mounted blob storage, and you have updated the endpoint's configuration. (You should suspend storage targets before modifying their private endpoints, as described in the [prerequisites article](hpc-cache-prerequisites.md#work-with-private-endpoints).)
-
-With a custom DNS system, it's possible for your NFS storage target's IP address to change because of back-end DNS changes. If your DNS server changes the back-end storage system's IP address, Azure HPC Cache can lose access to the storage system. Ideally, you should work with the manager of your cache's custom DNS system to plan for any updates, because these changes make storage unavailable.
-
-If you use a private endpoint for secure storage access, the endpoint's IP addresses can change if you modify its configuration. If you need to change your private endpoint configuration, you should suspend the storage target (or targets) that use the endpoint, then refresh their IP addresses when you re-activate them. Read [Work with private endpoints](hpc-cache-prerequisites.md#work-with-private-endpoints) for additional information.
-
-If you need to update a storage target's IP address, use the **Storage targets** page. Click the **...** symbol in the right column to open the context menu. Choose **Refresh DNS** to query the custom DNS server or private endpoint for a new IP address.
-
-![Screenshot of storage target list. For one storage target, the "..." menu in the far right column is open and these options appear: Flush, Suspend, Refresh DNS, Force remove, Resume (this option is disabled), and Delete.](media/refresh-dns.png)
-
-If successful, the update should take less than two minutes. You can only refresh one storage target at a time; wait for the previous operation to complete before trying another.
 
 ## Understand storage target state