SoftNAS® provides the ability to add Read Cache devices to a storage pool. Read Cache provides an additional layer of cache, in addition to RAM memory cache.  SSD is recommended for your Read Cache, but for Essentials instances, only object storage can be used and created. However, many instance sizes offer ephemeral drives which can be leveraged for caching purposes. SoftNAS recommends using an instance with ephemeral drives for this reason. See Selecting your Instance Size: Essentials on Azure for details. 

Configure Read Cache

1. Click the Storage Pools option under the Storage section in the Left Navigation Pane.
   The Storage Pools panel will be displayed with the list of all the existing storage pools that are already allocated. 
   
   
2. Create required storage pools as defined in the below documentation. 
   
   Creating Storage Pools
   
   For Essentials instances, only object storage can be used and created. However, many instance sizes offer ephemeral drives which can be leveraged for caching purposes. SoftNAS recommends using an instance with ephemeral drives for this reason. See Selecting your Instance Size: Essentials on Azure for details. 
   
   Note: The first time ephemeral disks are used in a pool, the 'force' option must be used to overwrite the default file-system. Remember that ephemeral devices are non-persistent and wiped on reboot.
   
   Note: SoftNAS recommends a Read Cache of at least 10% the size of your standard backup job.
   
   
3. On the Storage Pools panel, click the Details tab in the lower panel. 
   
   
4. Verify that no log or cache is listed under Pool Devices. 
   
   
5. Select the Storage Pool to which you wish to add a Read Cache.
   
   
6. Click the Read Cache option in the toolbar. 
   The Add Read Cache to Storage Pool dialog will be displayed.
   
   
   
   
7. Select the disk to use for Read Cache. 
   
   
8. Click the Add Cache button. 
   
   Your Read Cache is now configured.