What’s Hot Add?
As you may know, Nakivo Backup & Replication (NBR) supports multiple transport modes such as NBD (Network Block Device), NBDSSL, SAN and Hot Add (from Nakivo 6.1 and above). You must know that Hot Add is default transport mode in Nakivo 6.1 and above and if Hot Add is not available, system will switch over to LAN mode.
In order for the Hot Add feature to work for VM backup, replication, and recovery, the following requirements must be met:
- The Transporter that will be reading or writing data from/to the VM disks should run on a VM.
- The Transporter VM should:
- Be available in the product’s Inventory.
- Run on a host that has access to the datastore(s) with the VM disks.
- Run in the same datacenter as the VM to be processed.
The Hot Add feature is not available for VMs that contain IDE disks.
Hot Add Background
NAKIVO Backup & Replication can read data directly from source VM disks, bypassing the network, which can significantly increase job performance.
This is achieved with VMware’s Hot Add technology, which enables attaching source VM disks to a different VM and reading data directly from the disk.
Nakivo BR will take a snapshot from machines in backup job and attach snapshot VMDK to transporter machine. The transporter transfer data via ESXi to physical disks directly and it will improve backup performance.
You can see your transporter machine settings and you will find snapshot disk that it is attached to the transporter machine.
Also you can find all tasks which should be performed by Nakivo to take backup by Hot Add feature in tasks list on your ESXi server or vCenter server:
Hot Add Mode Cannot be Used
Sometimes, you will face with the below message when you want use Hot Add as transport mode:
Hot Add transport mode cannot be used by the transporter to access one or more disks of this VM.
Transporter VM is not in the Inventory
In order for Hot Add to function properly, the Transporter VM must be present in the Inventory.
To solve this issue, please add vCenter or ESXi host where NAKIVO Backup & Replication Transporter VM is running, to the Inventory.
Transporter VM is in a Different Datacenter
If NAKIVO Backup & Replication Transporter VM and the source VM are in a different datacenter, Hot Add will not be functional (even if there is a shared datastore).
To solve this problem, please deploy another Transporter VM in the same datacenter and select it in the job settings.
Backed Up VM Contains IDE Disks
Hot Add is not possible for VMs with IDE disks. If your source VM contains an IDE disk, Hot Add mode will not be applicable for the entire VM.
To solve this problem, please convert your virtual IDE disks into SCSI disks or process such VM by a separate job in LAN or SAN mode.
Transporter Doesn’t Have Access to Datastore
There are no Transporters that can attach all disks of this source VM.
For example, your Transporter may run on a host that does not have access to the datastore with your source VM’s disks.
Transporter and Backed Up VM Have Same BIOS UUID
If NAKIVO Backup & Replication Transporter VM and the source VM have the same BIOS UUID, Hot Add will not be functional.
To solve this problem, please deploy another VM with a Transporter that has a different BIOS UUID, and use it to back up your VM(s).
NOTE: If Hot Add cannot be enabled for at least one disk of a source VM (even if this disk is excluded in the job), Hot Add will be unavailable for the entire VM.