Proxy Server
With backup proxies you can easily scale Veeam backup infrastructure based on the organization demands:
In a basic installation (simple deployment scenario for smaller environments or Proof of Concepts) the backup proxy is automatically installed on the Veeam backup server as part of the Veeam Backup & Replication installation process.
In advanced deployment scenarios, the backup proxy role is usually assigned to one or more Windows servers. This approach allows for offloading the Veeam backup server, achieving better performance and a minimal backup window. Backup proxies can be deployed both in the primary site and in remote sites on any managed Microsoft Windows server in the infrastructure. Depending on the data transport mode you plan to use a backup proxy can be installed on a physical server or on a VM as explained later in this section.
A backup proxy handles data traffic between the VMware vSphere infrastructure and Backup & Replication during backup, replication (at source and target), VM copy, VM migration jobs or VM restore. They are also used to detect and scan snapshots to enable Veeam Explorer for Storage Snapshot features if a compatible storage system was added to the Backup & Replication Server.
Backup proxy operations include the following:
Retrieving VM data from production storage, compressing and sending it to the backup repository (for a backup job) or another backup proxy (for a replication job).
BitLooker: Applies to VMs running Windows OS and using NTFS. For more information, see the corresponding section of this guide > Deduplication and Compression - BitLooker
Inline source side data deduplication to optimize information received by vSphere Change Block Tracking (CBT)
Inline compression
AES256 encryption if the corresponding option is selected in the data transportation or backup data settings.
Technically a backup proxy runs a light-weight transport service that takes a few seconds to deploy. When you add a Windows-based server to Veeam backup management console assigning the proxy role to it Backup & Replication installs the necessary components starting the required services on that server. When a job is started the Veeam Backup & Replication server becomes the point of control for dispatching tasks to proxy servers using its built-in load balancing algorithm.
Like any backup vendor using VMware VADP, Backup & Replication integrates VMware VDDK in the Veeam Transport Service. This is necessary for management interaction with vCenter and ESXi hosts, while in some scenarios, VDDK is bypassed to optimize performance.
Backup data VDDK based transport modes underlay some limitations so Veeam developed it´s own more advanced communication protocols to address them. For example Veeam can backup multiple disks of the same VM at same time with HotAdd mode or can read data with Direct NFS mode directly out of NFS based storage systems.
Intelligent Load Balancing
To specify the threshold for proxy load an administrator uses the Max concurrent tasks proxy setting (where a task stands for a single VM disk), Backup & Replication uses a unique load balancing algorithm to automatically spread the load across multiple proxies. This feature allows you to increase backup performance, minimize backup time window and optimize data flow.
The default proxy server is configured for 2 simultaneous tasks at installation, whereas subsequently added proxy servers analyze the CPU configuration. The proxy server automatically proposes configuring 1 task per CPU core. During deployment, it is determined which datastores the proxy can access. This information is stored in the configuration database, and is used at backup time to automatically select the best transport mode depending on the type of connection between the backup proxy and datastore.
First Backup & Replication checks if data processing can be assigned to a backup proxy with the Direct Storage mode (which includes Direct SAN Access and Veeam's own special Direct NFS Access), then it checks whether a Virtual Appliance or Hot-Add proxy can be used. Then it looks for a Network Mode(NBD) proxy. For more details, see the “Transport Modes” section of this guide.
After the algorithm identifies all existing backup proxies it spreads the load across them in an optimal way:
It discovers the number of tasks being processed at the moment by each proxy and looks for the server with the lowest load and the best connection.
All tasks are standing in a “VM to process” queue, when a proxy’s task slot becomes free Backup & Replication will automatically fill it up with the next VM disk backup task.
Priority goes to the disk that belongs to an already processed VM, after that VMs of already running jobs have next higher priority.
Tip: At the repository, which writes the backup data, only one thread is writing to the backup storage per running job. If few jobs with a high number of VMs are processed simultaneously, you may experience that these threads are not sufficient to fully utilize backup storage performance. If throughput per I/O stream is a bottleneck, consider enabling "Per VM backup chains".
Tip: Default recommended value is 1 task per core/vCPU, with at least 2 CPUs. To optimize the backup window, you can cautiously oversubscribe the Max concurrent tasks count, but monitor CPU and RAM usage carefully.
Veeam Backup & Replication supports parallel processing of VMs/VM disks:
It can process multiple VMs within a Job simultaneously increasing data processing efficiency.
If a VM was created with multiple disks Veeam will try to process these disks simultaneously to reduce VM backup time to minimize VMware snapshot lifetime.
Priority goes to already running parallel processes for VM disks backups.
To achieve the best backup window it is recommended to slightly oversubscribe the tasks slots and start more jobs. This allow Veeam to leverage the maximum of the task slots and lead into an optimal backup window.
Note: Parallel processing is a global setting that is turned on by default. If you had upgraded from older versions please check and enable this setting.
Backup Proxy Services and Components
Veeam backup proxy uses the following services and components:
Veeam Installer Service - A service that is installed and started on the Windows server once it is added to the list of managed servers in the Veeam Backup & Replication console. This service analyses the system, installs and upgrades necessary components and services.
Veeam Transport Service – A service responsible for deploying and coordinating executable modules that act as "data movers". It performs main job activities on behalf of Veeam Backup & Replication (communicating with VMware Tools, copying VM files, performing data deduplication and compression, and so on).
VeeamAgent.exe process - a data mover which can be started multiple times (on demand) for each data stream on the proxy. These processes can operate in either read or write mode. When used on a proxy server for backup, they are only performing read operations, while "write" mode is used for writing data on a target backup proxy (replication). Veeam agents in write mode are also used on all repository types, but will not be discussed in this chapter.