Introduction
This document is intended to guide customers and Nasuni Support personnel to add cache space to the Nasuni Edge Appliance by configuring additional virtual cache disks.
Important: Configuring additional cache disks is only possible for Nasuni Edge Appliances whose original version was 7.9 or later.
Important: For versions 9.3 and later, if multiple cache disks are provided before the first boot, Nasuni automatically provisions them as a striped set for best performance. Multiple cache disks must all be the same size, or the size of the smallest cache disk determines how much of each disk can be used.
Step 1: Customer Adds Virtual Cache Disk
The customer adds another virtual disk to the virtual machine for the Nasuni Edge Appliance. The size of the additional virtual disk does not matter. The customer can make the additional virtual disk small initially, with the intention of growing it later, or start with it already large.
See Adding Cache Disks to use as instructions for this procedure.
When this procedure is complete, there should now be more than one cache disk for the Nasuni Edge Appliance.
The customer should also enable Remote Support for the Nasuni Edge Appliance.
Step 2: Discover the Added Virtual Cache Disk (Nasuni Support)
After the customer has added the virtual cache disk to the Nasuni Edge Appliance, Nasuni Support discovers the new virtual cache disks.
As a double-check, Nasuni Support confirms the size of the newly added device with the customer.
Step 3: Join the Newly Added Virtual Cache Disk to the Existing Cache Disks (Nasuni Support)
After verifying the newly added device, Nasuni Support joins the newly added device to the existing cache disks. The combined cache automatically grows to fill the available space.
Important: The size of the COW disk should be at least 1/4 of the size of the cache disk. The COW disk need not be larger than 250 GiB, except in special situations where ingestion might exceed the size of the cache disk, such as during initial ingestion or when ingesting extremely large files. In such cases, consult Nasuni Support.
Tip: Although the Nasuni Edge Appliance issues a warning during startup if the COW disk is too small relative to the cache, the Nasuni Edge Appliance does not issue this warning if the COW disk is larger than 250 GiB.
Nasuni Support notifies the customer that the procedure is complete, and that the customer can continue to use the Nasuni Edge Appliance with the expanded cache.
Note: The usual rule for cache growth also applies here: you can only make cache disks larger and can never make cache disks smaller.