docs(incremental_backups): explain NBD

docs/incremental_backups.md

@@ -64,3 +64,24 @@ For example, with a value of 2, the first two backups will be a key and a delta,
 This is important because on rare occasions a backup can be corrupted, and in the case of incremetnal backups, this corruption might impact all the following backups in the chain. Occasionally performing a full backup limits how far a corrupted delta backup can propagate.
 
 The value to use depends on your storage constraints and the frequency of your backups, but a value of 20 is a good start.
+
+## NBD-enabled Backups
+
+You have the option to utilize the NBD network protocol for data transfer instead of the VHD handler generated by the XAPI. NBD-enabled backups generally show improved speed as the load on the Dom0 is reduced.
+
+To enable NBD on the pool network, select the relevant pool, and navigate to the Network tab to modify the parameter:
+
+![](./assets/nbd-connection.png)
+
+This will securely transfer encrypted data from the host to the XOA.
+When creating or editing an incremental (previously known as delta) backup and replication for this pool in the future, you have the option to enable NBD in the Advanced settings:
+
+![](./assets/nbd-enable.png)
+
+After the job is completed, you can verify whether NBD was used for the transfer in the backup log:
+
+![](./assets/backuplog.png)
+
+It's important to note that NBD exports are not currently visible in the task list before 5.90 (december 2023).
+
+To learn more about the evolution of this feature across various XO releases, check out our blog posts for versions [5.76](https://xen-orchestra.com/blog/xen-orchestra-5-76/), [5.81](https://xen-orchestra.comblog/xen-orchestra-5-81/), [5.82](https://xen-orchestra.com/blog/xen-orchestra-5-82/), and [5.86](https://xen-orchestra.com/blog/xen-orchestra-5-86/).