Using VMware transport libraries
This article applies to VMware VADP backup sets. The VMware transport libraries are included with DS-Client to allow VMware to take advantage of different ‘transport modes’ if supported by the VMware configuration.
• NBD/NBDSSL transport mode will be always be attempted if DS-Client does not have direct access to the VMware VMFS data store.
• HotAdd transport mode will be always be attempted if DS-Client is running on a virtual machine and has direct access to the VMware VMFS datastore over the FC / FCoE / iSCSI.
• SAN transport mode must be explicitly selected when restoring the backup set (“Use SAN with all disk types” option). It will work only if DS-Client is running on a physical machine and has direct access to the VMware VMFS datastore over the FC / FCoE / iSCSI.
For backup, DS-Client will automatically use the most efficient transport mode available.
Details
By default, DS-Client uses VADP and VDDK APIs to interact with the VMWare ESXi environment for backup and restore. The latest release (as of the revision date of this article) contains additional capabilities with the VMware transport libraries plug-in.
The following VMware Virtual Disk Transport Methods are available to speed up the backup and restore processes:
NBD/NBDSSL (Network Block Device) transport mode
The NBD/NBDSSL transport mode allows you to transfer backup and recovery data through the LAN when DS-Client is running on a physical or virtual machine and it does not have direct access to the VMware VMFS datastore through the FC / FCoE / iSCSI.
NBD/NBDSSL transport mode configuration description:
1. DS-Client runs on a physical or virtual machine.
2. Using the NBD/NBDSSL transport mode, DS-Client reads data where the .vmdk virtual disks are stored.
3. DS-Client accesses the VMFS data store and obtains the (CBT) changed blocks of the virtual machines.
4. All data is transferred over the LAN from the ESXi host to DS-Client.
5. DS-Client deduplicates, compresses and encrypts the virtual machines and sends them to DS-System.
6. DS-System stores the backed up virtual machines in the DS-System online storage.
7. For restores, the same DS-Client reads the backed up data from the DS-System Online Storage. DS-Client decompresses, decrypts and builds the virtual machine’s disks from the backup data into its native ‘.vmdk’ format.
8. DS-Client transfers the virtual machine’s disks to the VMware ESXi storage through the LAN using the NBD/NBDSSL transport mode.
9. The virtual machines are now available to be turned on at any time.
SAN transport mode
The SAN (Storage Area Network) transfer mode allows you to transfer backup and recovery data through the SAN when the DS-Client is running on a physical machine and it has direct access to the VMware VMFS datastore through FC / FCoE / iSCSI.
SAN transport mode configuration description:
1. DS-Client runs on a physical machine.
2. Using the SAN transport mode, DS-Client reads data directly from the SAN storage where the .vmdk virtual disks are stored.
3. DS-Client accesses the VMFS data store and obtains the (CBT) changed blocks of the virtual machines.
4. No data is transferred through the LAN from the ESXi host to DS-Client.
5. DS-Client deduplicates, compresses and encrypts the virtual machines and sends them to DS-System.
6. DS-System stores the backed up virtual machines in the DS-System online storage at the Remote Offsite Data Center.
7. For restores, the same DS-Client reads the backed up data from the DS-System Online Storage. DS-Client decompresses, decrypts and builds the virtual machine’s disks from the backup data into its native ‘.vmdk’ format.
8. DS-Client transfers the virtual machine’s disks to the VMware ESXi storage through the SAN using the SAN transport mode. No data is transferred from DS-Client to the ESXi host through the LAN.
9. The virtual machines are now available to be turned on at any time.
NOTE: When using this method, DS-Client automatically disables the CBT parameters in the virtual machine advanced settings when it is doing the restore process.
HotAdd transport mode
The HotAdd Transport Mode allows you to transfer backup and recovery data through the SAN when DS-Client is running on a virtual machine and it has direct access to the VMware VMFS data store through the FC / FCoE / iSCSI. This is supported only when the virtual machines that are being backed up are using SCSI virtual disks.
HotAdd transport mode configuration description:
1. DS-Client runs on a virtual machine.
2. Using the HotAdd transport mode, DS-Client reads data directly from the SAN storage where the .vmdk virtual disks are stored.
3. DS-Client accesses the VMFS data store and obtains the (CBT) changed blocks of the virtual machines
4. No data is transferred through the LAN from the ESXi host to DS-Client.
5. DS-Client deduplicates, compresses and encrypts the virtual machines and sends them to DS-System.
6. DS-System stores the backed up virtual machines in the DS-System online storage at the Remote Offsite Data Center.
7. For restores, the same DS-Client reads the backed up data from the DS-System Online Storage. DS-Client decompresses, decrypts and builds the virtual machine’s disks from the backup data into its native ‘.vmdk’ format.
8. DS-Client transfers the virtual machine’s disks to the VMware ESXi storage through the SAN using the HotAdd transport mode. No data is transferred from the Remote DS-VDR to the ESXi host through the LAN.
9. The virtual machines are now available to be turned on at any time.