VMware VADP backup recommendations:
Following is a list of best practices for configuration, backup, recovery and error management for the VADP backup set.
1. ESXi host vs vCenter server:
a. If the ESXi host is Managed by vCenter server, it is strongly recomended to create, run and restore a backup set thorugh the vCenter server with a user credentials, included into the Administrator group.
b. The Standalone (unmanaged) ESXi host only can be used for a backup set creating, running and restoring.
Note: You can find more about Managed and Standalone ESXi Hosts on VMware vSphere Documentation Center: https://pubs.vmware.com/vsphere-50/index.jsp?topic=%2Fcom.vmware.wssdk.pg.doc_50%2FPG_Ch4_Introduction_Inventory.6.7.html
2. Hardware version of the virtual machines hosting DS-Client or Remote DS-VDR:
a. If the DS-Client or Remote DS-VDR runs inside a virtual machine (on ESXi) ensure the hardware version of virtual machine hosting these Asigra modules is equal to or higher than the hardware version of the virtual machines that will be backed up.
For details please check the VMware KB 1010675:
3. Lastest VMware patches applied:
a. VMware vCenter, VMware ESXi hosts and VMware Tools on the virtual machines, to be backed up, should have applied the latest VMware patches available for the VMware version used.
4. Avoid using special characters when naming datastores, folders, or virtual machines
a. The VMware vCenter Server and ESX/ESXi Server do not escape special characters used in the display names; for more information please reference VMware KB article: Troubleshooting issues with virtual machines or datastore names containing special characters (2046088)
As a workaround you may consider, creating folders without special characters in their names and moving the VM into the newly created folder. This requires that the backup items list be refreshed in the DS-User backup set properties.
5. First backup and CBT option:
a. When backing up a virtual machine (VMware VADP set) for the first time with CBT option enabled, the VM should NOT have any snapshots.
6. VMware vCenter administrator credentials
a. When creating a VMware VADP backup set, please use the VMware vCenter administrator credentials (preferable) or a username that has full permissions on the ESXi environment to be backed up.
7. Critical VMware patch for silent failure of VADP backups with CBT option enabled
a. VMware has released patches for ESXi 5.0, 5.1, and 5.5 to address the silent failure of VADP backups with CBT option enabled (backup incorrectly taken if the vmdk backed up was expanded over the 128 GB boundary), please see VMware KB article kb.vmware.com/kb/2090639 for resolution.
b. VMware has released the patch ESXi600-201511001 for ESXi 6.0.x to address a silent failure of VADP backups with CBT option enabled (Backing up a Changed Block Tracking enabled virtual machine in ESXi 6.0.x returns incorrect changed sectors), see VMware KB 2136854 for resolution.
8. CBT and local storage backup
a. This is currently not supported, when backing up to Local Storage, CBT option is ignored.
When setting up VMware VADP backup sets, both the Local Storage and CBT options can be checked. However, CBT backup cannot be performed on Local Storage, Local Only or Self-Contained as for these types of storages each generation is independent from other generations.
9. HotAdd prerequisites:
- The DS-Client must be a virtual machine for HotAdd. HotAdd transport mode uses attached virtual disks to the DS-Client Server;
- The DS-Client must have access to the datastore where the target VMs are located;
- The target VM disks must be SCSI. IDE disks are not supported in HotAdd;
- The VMware Tools is a must the ecah VM and and the DS-Client;
- The VM hardware versions should be the same or older as the DS-Client's one;
- The DS-Client with a single SCSI controller will have 15 disks maximum attached. If it is requred more than 15 disks backed up at the same time, you need to add more SCSI controllers to the DS-Client;
- The datastore should have sufficient space for target VM disks snapshots;
- If there is a standalone ESXi host only (no vCenter management), the DS-Client will backup the VMs which are located on the same ESXi host;
- DS-Client and target VMs should be located in the same cluster (managed by the same vCenter);
- DS-Client may fail to backup trget VMs which are located on another standalone server or cluster;
- "Automount” disabled is recomended on the DS-Client server (see the item 11 below).
10. Restoration on thin-provisioned disks:
a. To avoid thin-provisioned backups restoring as thick-provisioned when the CBT option is enabled, ensure that the virtual machine is successfully powered on before the initial backup occurs. For details see VMware KB:
11. Automatic removal of snapshots
a. The DS-Client and Remote DS-VDR removes the snapshot automatically at the end of the backup or restore activities on the virtual machine backed up or restored; if any of these Asigra modules are stopped while such operation is in progress, the snapshot cannot be removed automatically and must be manually removed (extra care must be paid when the hotadd transport method is used during backup or restore, for details see the FAQ with ID 3102 here on Asigra Web Support site, "Knowledge Base" section).
b. According to VDDK programming guide, it is recommended to disable the automount option for the Windows DS-Client computer (if hotadd mode is taken use of).
Disabling Automount in Windows DS-Client computer
When using HotAdd transport from a Windows DS-Client, it can make unwanted changes to HotAdded volumes. To prevent this, Windows automount should be disabled on the Windows DS-Client computer.
To disable Windows automount:
//Start DiskPart by opening an elevated command prompt window and typing the commmand below:
DISKPART> automount disable
//Prevent any previously mounted volumes from being re‐mounted the next time.
DISKPART> automount scrub
12. Windows VMs failing with Quiesce I/O errors:
a. If the backups for VADP sets protecting virtual machines running Windows fail with errors related to quiesce I/O apply the resolution described in VMware KB:
13. Modified backup set options not being applied
a. If the backup set options (e.g. enable CBT) have been applied, but not actually being changed on the backup set, it is recommended to create a new backup set instead of editing the existing one.