Veeam Backup & Replication provides a set of features for building and maintaining a flexible backup infrastructure, performing data protection tasks (such as VM backup, replication, copying backup files), and carrying out disaster recovery procedures. This article contains a high-level step by step guide of Veeam Backup & Replication, its architecture, features, data protection and disaster recovery concepts necessary to understand Veeam Backup & Replication background operations and processes.
Solution Architecture
Veeam Backup & Replication is a modular solution that lets you build a scalable backup infrastructure for environments of different sizes and configuration. The installation package of Veeam Backup & Replication includes a set of components that you can use to configure the backup infrastructure. Some components are mandatory and provide core functionality; some components are optional and can be installed to provide additional functionality for your business and deployment needs.
You can co-install Veeam Backup & Replication components on the same machine, physical or virtual, or you can set them up separately for a more scalable approach.
Components
The Veeam backup infrastructure comprises a set of components. Some components can be deployed with the help of the setup file. Other components can be deployed via the Veeam Backup & Replication console.
Backup Server
The backup server is a Windows-based physical or virtual machine on which Veeam Backup & Replication is installed. It is the core component in the backup infrastructure that fills the role of the “configuration and control center”. The backup server performs all types of administrative activities:
Coordinates backup, replication, recovery verification and restore tasks
Controls job scheduling and resource allocation
Is used to set up and manage backup infrastructure components as well as specify global settings for the backup infrastructure
In addition to its primary functions, a newly deployed backup server also performs the role of the default backup repository, storing backups locally.
The backup server uses the following services and components:
Veeam Backup Service is a Windows service that coordinates all operations performed by Veeam Backup & Replication such as backup, replication, recovery verification and restore tasks. The Veeam Backup Service runs under the Local System account or account that has the Local Administrator permissions on the backup server.
Veeam Backup & Replication Console provides the application user interface and allows user access to the application's functionality.
Veeam Guest Catalog Service is a Windows service that manages guest OS file system indexing for VMs and replicates system index data files to enable search through guest OS files. Index data is stored in the Veeam Backup Catalog — a folder on the backup server. The Veeam Guest Catalog Service running on the backup server works in conjunction with search components installed on Veeam Backup Enterprise Manager and (optionally) a dedicated Microsoft Search Server.
Veeam Backup & Replication Configuration Database is used to store data about the backup infrastructure, jobs, sessions and so on. The database instance can be located on a SQL Server installed either locally (on the same machine where the backup server is running) or remotely.
Veeam Backup PowerShell Snap-In is an extension for Microsoft Windows PowerShell 2.0. Veeam Backup PowerShell adds a set of cmdlets to allow users to perform backup, replication and recovery tasks through the command-line interface of PowerShell or run custom scripts to fully automate operation of Veeam Backup & Replication.
Mount server is a component required for browsing the VM guest file system and restoring VM guest OS files and application items to the original location.
Backup & Replication Console
The Veeam Backup & Replication console is a separate client-side component that provides access to the backup server. The console is installed locally on the backup server by default. You can also use it in a standalone mode — install the console on a dedicated machine and access Veeam Backup & Replication remotely over the network. The console lets you log in to Veeam Backup & Replication and perform all kind of data protection and disaster recovery operations as if you work on the backup server.
To log in to Veeam Backup & Replication via the console, the user must be added to the Local Users group on the backup server or a group of domain users who have access to the backup server. The user can perform the scope of operations permitted by his or her role in Veeam Backup & Replication.
You can install as many remote consoles as you need so that multiple users can access Veeam Backup & Replication simultaneously. Veeam Backup & Replication prevents concurrent modifications on the backup server. If several users are working with Veeam Backup & Replication at the same time, the user who saves the changes first has the priority. Other users will be prompted to reload the wizard or window to get the most recent information about the changes in the configuration database.
If you have multiple backup servers in the infrastructure, you can connect to any of them from the same console. For convenience, you can save several shortcuts for these connections.
To make users' work as uninterrupted as possible, the remote console maintains the session for 5 minutes if the connection is lost. If the connection is re-established within this period, you can continue working without re-logging to the console.
When you install a remote console on a machine, Veeam Backup & Replication installs the following components:
Veeam Backup PowerShell Snap-In
Veeam Explorer for Microsoft Active Directory
Veeam Explorer for Microsoft Exchange
Veeam Explorer for Oracle
Veeam Explorer for Microsoft SQL
Veeam Explorer for Microsoft SharePoint
Mount server
The console does not have a direct access to the backup infrastructure components and configuration database. Such data as user credentials, passwords, roles and permissions are stored on the backup server side. To access this data, the console needs to connect to the backup server and query this information periodically during the work session.
Requirements and Limitations for Remote Console
The machine on which you install the Veeam Backup & Replication console must meet the following requirements:
The remote console can be installed on a Microsoft Windows machine (physical or virtual).
If you install the console remotely, you can deploy it outside NAT. However, the backup server must be behind NAT. The opposite type of deployment is not supported: if the backup server is deployed outside NAT and the remote console is deployed behind NAT, you will not be able to connect to the backup server.
The Veeam Backup & Replication console has the following limitations:
You cannot perform restore from the configuration backup via the remote console.
The machines on which the remote console is installed are not added to the list of managed servers automatically. For this reason, you cannot perform some operations, for example, import backup files that reside on the remote console machine or assign roles of backup infrastructure components to this machine. To perform these operations, you must add the remote console machine as a managed server to Veeam Backup & Replication.
Off-Host Backup Proxy
By default, when you perform backup and replication jobs in the Hyper-V environment, VM data is processed directly on the source Hyper-V host where VMs reside, and then moved to the target, bypassing the backup server.
VM data processing can produce unwanted overhead on the production Hyper-V host and impact performance of VMs running on this host. To take data processing off the production Hyper-V host, you can use the off-host backup mode.
The off-host mode shifts the backup and replication load to a dedicated machine — an off-host backup proxy. The off-host backup proxy functions as a “data mover” which retrieves VM data from the source datastore, processes it and transfers to the destination.
The machine performing the role of an off-host backup proxy must meet the following requirements:
The role of an off-host backup proxy can be assigned only to a physical Microsoft Windows 2008 Server R2 machine with the Hyper-V role enabled, Windows Server 2012 machine with the Hyper-V role enabled or Windows Server 2012 R2 machine with the Hyper-V role enabled.
For evaluation and testing purposes, you can assign the off-host backup proxy role to a VM. To do this, you must enable the Hyper-V role on this VM (use nested virtualization). However, it is not recommended that you use such off-host backup proxies in the production environment.
The off-host backup proxy must have access to the shared storage where VMs to be backed up, replicated or copied are hosted.
To create and manage volume shadow copies on the shared storage, you must install a VSS hardware provider that supports transportable shadow copies on the off-host proxy and the Hyper-V host. The VSS hardware provider is usually distributed as a part of client components supplied by the storage vendor.
When you assign the role of an off-host backup proxy to the selected machine, Veeam Backup & Replication automatically installs on it light-weight components and services required for backup proxy functioning. Unlike the backup server, backup proxies do not require a dedicated SQL database — all settings are stored centrally, within the configuration database used by Veeam Backup & Replication.
To enable a Hyper-V host or a Windows machine to act as an off-host backup proxy,
Veeam Backup & Replication installs the following services on it:
Veeam Installer Service is an auxiliary service that is installed and started on any Windows (or Hyper-V) server once it is added to the list of managed servers in the Veeam Backup & Replication console. This service analyzes the system, installs and upgrades necessary components and services.
Veeam Transport is responsible for deploying and coordinating executable modules that act as "data movers" and perform main job activities on behalf of Veeam Backup & Replication, such as performing data deduplication, compression and so on.
Veeam Hyper-V Integration Service is responsible for communicating with the VSS framework during backup, replication and other jobs, and performing recovery tasks. The service also deploys a driver that handles changed block tracking for Hyper-V.
Guest Interaction Proxy
To interact with the VM guest OS during the backup or replication job, Veeam Backup & Replication needs to deploy a runtime process in each VM. Guest OS interaction is performed if you enable the following options in the job:
Application-aware processing
Guest file system indexing
Transaction logs processing
Previously, the runtime process on all VMs was deployed by the backup server. This could cause the following problems:
The load on the backup server was high.
If a connection between two sites was slow, the job performance decreased.
If the backup server had no network connection to VMs, application-aware processing tasks were not accomplished for these VMs.
Starting from Veeam Backup & Replication 9.0, the task of deploying the runtime process in a Microsoft Windows VM is performed by the guest interaction proxy. The guest interaction proxy is a backup infrastructure component that sits between the backup server and processed VM. The guest interaction proxy deploys the runtime process in the VM and sends commands from the backup server to the VM.
The guest interaction proxy allows you to communicate with the VM guest OS even if the backup server and processed VM run in different networks. As the task of runtime process deployment is assigned to the guest interaction proxy, the backup server only has to coordinate job activities.
Important!
The guest interaction proxy deploys the runtime process only in Microsoft Windows VMs. In VMs with another guest OS, the runtime process is deployed by the backup server.
You can use multiple guest interaction proxies to improve performance. Multiple guest interaction proxies will deploy runtime processes in VMs faster compared to the same operation performed by one guest interaction proxy.
In a backup infrastructure with multiple remote sites, you can deploy a guest interaction proxy in each site. This can reduce load on the backup server and produce less traffic between the backup server and remote site. The backup server will only have to send commands to the guest interaction proxies.
Requirements for Guest Interaction Proxy
To perform the role of guest interaction proxy, the machine must meet the following requirements:
It must be a Microsoft Windows machine (physical or virtual).
You must add it to the Veeam Backup & Replication console as a managed server.
It must have a LAN connection to the VM that will be backed up or replicated.
The guest interaction proxy role can be performed by any machine that meets the requirements, including backup proxy, backup repository, WAN accelerator, Microsoft Hyper-V host or backup server.
Note:
The guest interaction proxy functionality is available in the Enterprise and Enterprise Plus Editions of Veeam Backup & Replication.
Guest Interaction Proxy Selection
When you add a Microsoft Windows machine to the backup infrastructure, Veeam Backup & Replication deploys the Data Mover Service on it. The Data Mover Service includes the components responsible for runtime process deployment during guest OS interaction.
To assign a guest interaction proxy for the job, you must select a Microsoft Windows machine that will perform the role of the guest interaction proxy at the Guest Processing step of the backup or replication job wizard. You can assign the guest interaction proxy manually, or let Veeam Backup & Replication do it automatically. Veeam Backup & Replication uses the following priority rules to select the guest interaction proxy:
A machine in the same network as the protected VM that does not perform the backup server role.
A machine in the same network as the protected VM that performs the backup server role.
A machine in another network that does not perform the backup server role.
A machine in another network that performs the backup server role.
If Veeam Backup & Replication finds several available machines of equal priority, it selects the less loaded machine. The load is defined by the number of tasks that the machine already performs.
Failover from Guest Interaction Proxy to Backup Server
If the guest interaction proxy fails to connect to a Microsoft Windows VM, the guest interaction proxy will not be able to access the VM and deploy a runtime process in it. In this case, the backup server will take over the role of guest interaction proxy and deploy the runtime process in the VM.
Backup Repository
A backup repository is a storage location where you can keep backup files and metadata for replicated VMs. You can configure the following types of backup repositories in the backup infrastructure:
Simple Backup Repository
A backup repository is a location used by Veeam Backup & Replication jobs to store backup files.
Technically, a backup repository is a folder on the backup storage. By assigning different repositories to jobs and limiting the number of parallel jobs for each one, you can balance the load across your backup infrastructure.
In the Veeam backup infrastructure, you can use one of the following repository types:
Microsoft Windows server with local or directly attached storage. The storage can be a local disk, directly attached disk-based storage (such as a USB hard drive), or iSCSI/FC SAN LUN in case the server is connected into the SAN fabric.
On a Windows repository, Veeam Backup & Replication deploys a local Veeam Data Mover Service (when you add a Windows-based server to the product console, Veeam Backup & Replication installs a set of components including the Veeam Data Mover Service on that server). When any job addresses the backup repository, the Veeam Data Mover Service on the backup repository establishes a connection with the source-side Veeam Data Mover Service on the backup proxy, enabling efficient data transfer over LAN or WAN.
Linux server with local, directly attached storage or mounted NFS. The storage can be a local disk, directly attached disk-based storage (such as a USB hard drive), NFS share, or iSCSI/FC SAN LUN in case the server is connected into the SAN fabric.
When any task addresses a Linux repository, Veeam Backup & Replication deploys and starts the Veeam Data Mover Service on the backup repository. The Data Mover Service establishes a connection with the source-side Data Mover Service on the backup proxy, enabling efficient data transfer over LAN or WAN.
CIFS (SMB) share. SMB share cannot host Veeam Data Mover Services. For this reason, data to the SMB share is written from the gateway server. By default, this role performs an on-host or off-host backup proxy that is used by the job for data transport.
However, if you plan to move VM data to an offsite SMB repository over a WAN link, it is recommended that you deploy an additional gateway server in the remote site, closer to the SMB repository.
Veeam Backup & Replication will deploy a Veeam Data Mover Service on this gateway server, which will improve data transfer performance.
Deduplicating storage appliance. Veeam Backup & Replication supports the following deduplicating storage appliances:
EMC Data Domain
ExaGrid
HPE StoreOnce
Scale-Out Backup Repository
You can configure a scale-out backup repository in the backup infrastructure.
The scale-out backup repository is a logical entity. It groups several simple backup repositories, or extents. When you configure the scale-out backup repository, you actually create a pool of storage devices and systems, summarizing their capacity.
You can expand the scale-out backup repository at any moment. For example, if backup data grows and the backup repository reaches the storage limit, you can add a new storage system to the scale-out backup repository. The free space on this storage system will be added to the capacity of the scale-out backup repository. As a result, you will not have to move backups to a backup repository of a larger size.
To deploy a scale-out backup repository, you must configure a number of simple backup repositories and include them into the scale-out backup repository as extents. You can mix backup repositories of different types in one scale-out backup repository:
Microsoft Windows backup repositories
Linux backup repositories
Shared folders
Deduplicating storage appliances
For example, you can add a Microsoft Windows server and deduplicating storage appliance to the same scale-out backup repository.
You can use the scale-out backup repository for the following types of jobs and tasks:
Backup jobs.
Backup copy jobs. You can copy backups that reside on scale-out backup repositories and store backup copies on scale-out backup repositories.
VeeamZIP tasks.
Backup files stored on the scale-out repository can be used for all types of restores, replication from backup and backup copy jobs. You can verify such backups with SureBackup jobs. The scale-out backup repository can be used as a staging backup repository for restore from tape media. Files restored from the tape media are placed to the extents according to data placement policy configured for the scale-out backup repository.
Limitations for Scale-out Backup Repositories
The scale-out backup repository has the following limitations:
The scale-out backup repository functionality is available only in Enterprise and Enterprise Plus editions of Veeam Backup & Replication.
If you configure a scale-out backup repository and then downgrade to the Standard license, you will not be able to run jobs targeted at the scale-out backup repository. However, you will be able to perform restore from the scale-out backup repository.
You cannot use the scale-out backup repository as a target for the following types of jobs:
Configuration backup job
Replication jobs
Endpoint backup jobs
You cannot add a backup repository as an extent to the scale-out backup repository if any job of unsupported type is targeted at this backup repository or if the backup repository contains data produced by jobs of unsupported types (for example, replica metadata). To add such backup repository as an extent, you must first target unsupported jobs to another backup repository and remove the job data from the backup repository.
You cannot use a scale-out backup repository as a cloud repository. You cannot add a cloud repository as an extent to the scale-out backup repository.
You cannot use a backup repository with rotated drives as an extent to a scale-out backup repository. Even you enable the This repository is backed up by rotated hard drives setting for an extent, Veeam Backup & Replication will ignore this setting and use an extent as a simple backup repository.
If a backup repository is added as an extent to the scale-out backup repository, you cannot use it as a regular backup repository.
You cannot add a scale-out backup repository as an extent to another scale-out backup repository.
You cannot add a backup repository as an extent if this backup repository is already added as an extent to another scale-out backup repository.
You cannot add a backup repository on which some activity is being performed (for example, a backup job or restore task) as an extent to the scale-out backup repository.
If you use Enterprise Edition of Veeam Backup & Replication, you can create 1 scale-out backup repository with 3 extents for this scale-out backup repository. Enterprise Plus Edition has no limitations on the number of scale-out backup repositories or extents.
Extents
The scale-out backup repository can comprise one or more extents. The extent is a standard backup repository configured in the backup infrastructure. You can add any simple backup repository, except the cloud repository, as an extent to the scale-out backup repository.
The backup repository added to the scale-out backup repository ceases to exist as a simple backup repository. You cannot target jobs to this backup repository. Instead, you have to target jobs at the configured scale-out backup repository.
On every extent, Veeam Backup & Replication creates the definition.erm file. This file contains a description of the scale-out backup repository and information about its extents.
Extents inherit most configuration settings from the underlying backup repositories. The following settings are inherited:
Number of tasks that can be performed simultaneously
Read and write data rate limit
Data decompression settings
Block alignment settings
The following settings are not inherited:
Rotated drive settings. Rotated drive settings are ignored and cannot be configured at the level of the scale-out backup repository.
Per-VM backup file settings. Per-VM settings can be configured at the level of the scale-out backup repository.
Limitations, specific for certain types of backup repositories, apply to extents. For example, if you add EMC Data Domain as an extent to the scale-out backup repository, you will not be able to create a backup chain longer than 60 points on this scale-out backup repository.
Extents of the scale-out backup repository should be located in the same site. Technically, you can add extents that reside in different sites to the scale-out backup repository. However, in this case Veeam Backup & Replication will have to access VM backup files on storage devices in different locations, and the backup performance will degrade.
Backup File Placement
Veeam Backup & Replication stores backup files on all extents of the scale-out backup repository.
When you configure a scale-out backup repository, you must set the backup file placement policy for it. The backup file placement policy describes how backup files are distributed between extents. You can choose one of two policies:
Data locality — all backup files that belong to the same backup chain are stored on the same extent of the scale-out backup repository.
The Data locality policy does not put any limitations to backup chains. A new backup chain may be stored on the same extent or another extent. For example, if you create an active full backup, Veeam Backup & Replication may store the full backup file to another extent, and all dependent incremental backup files will be stored together with this full backup file.
However, if you use a deduplicating storage appliance as an extent to the scale-out backup repository, Veeam Backup & Replication will attempt to place a new full backup to the extent where the full backup from the previous backup chain resides. Such behavior will help increase the data deduplication ratio.
Performance — full backup files and incremental backup files that belong to the same backup chain are stored on different extents of the scale-out backup repository. If necessary, you can explicitly specify on which extents full backup files and incremental backup files must be stored.
The Performance policy can improve performance of transform operations if you use raw data devices as extents. When Veeam Backup & Replication performs transform operations, it needs to access a number of backup files in the backup repository. If these files are located on different storages, the I/O load on the storages hosting backup files will be lower.
If you set the Performance policy, you must make sure that the network connection between extents is fast and reliable. You must also make sure all extents are online when the backup job, backup copy job or a restore task starts. If any extent hosting backup files in the current backup chain is not available, the backup chain will be broken, and Veeam Backup & Replication will not be able to complete the task. To avoid data loss in this situation, you can enable the Perform full backup when required extent is offline option for the scale-out backup repository. With this option enabled, Veeam Backup & Replication will create a full backup instead of incremental backup if some files are missing from the backup chain.
The backup file placement policy is not strict. If the necessary extent is not accessible, Veeam Backup & Replication will disregard the policy limitations and attempt to place the backup file to the extent that has enough free space for the backup file.
For example, you have set the Performance policy for the scale-out backup repository and specified that full backup files must be stored on Extent 1 and incremental backup files must be stored on Extent 2. If before an incremental backup job session Extent 2 goes offline, the new incremental backup file will be placed to Extent 1.
Extent Selection
To select an extent for backup file placement, Veeam Backup & Replication checks the following conditions:
Availability of extents on which backup files reside. If some extent with backup files from the current backup chain is not accessible, Veeam Backup & Replication will trigger a full backup instead of incremental (if this option is enabled).
Backup placement policy set for the scale-out backup repository.
Load control settings — maximum number of tasks that the extent can process simultaneously.
Amount of free space available on the extent — the backup file is placed to the extent with the most amount of free space.
Availability of files from the current backup chain — extents that host incremental backup files from the current backup chain (or current VM) have a higher priority than extents that do not host such files.
At the beginning of the job session, Veeam Backup & Replication estimates how much space the backup file requires and checks the amount of free space on extents. Veeam Backup & Replication assumes that the following amount of space is required for backup files:
For per-VM backup chains: the size of the full backup file is equal to 50% of source VM data. The size of an incremental backup file is equal to 10% of source VM data.
This mechanism is also applied to backup files created with backup copy jobs.
For single file backup chains: the size of the full backup file is equal to 50% of source data for all VMs in the job. For the first incremental job session, the size of an incremental backup file is equal to 10% the full backup file. For subsequent incremental job sessions, the size of an incremental backup file is equal to 100% of the previous incremental backup file.
Extent Selection for Backup Repositories with Performance Policy
If you set the Performance policy for the scale-out backup repository, Veeam Backup & Replication always stores full backup files and incremental backup files that belong to the same backup chain on different extents. To choose the extent to which a backup file can be stored, Veeam Backup & Replication applies this policy and policies mentioned above.
For example, a scale-out backup repository has 2 extents that have 100 GB and 200 GB of free space. You set the Performance policy for the scale-out backup repository and define that all types of backup files (full and incremental) can be placed on both extents.
When a backup job runs, Veeam Backup & Replication picks the target extent in the following manner:
During the first job session, Veeam Backup & Replication checks to which extent a full backup file can be stored. As both extents can host the full backup file, Veeam Backup & Replication checks which extent has more free space, and picks the extent that has 200 GB of free space.
During incremental job session, Veeam Backup & Replication checks to which extent an incremental backup file can be stored. As both extents can host the incremental backup file, Veeam Backup & Replication picks the extent that does not store the full backup file — the extent that has 100 GB of free space.
Service Actions with Scale-Out Backup Repositories
You can perform service actions with extents of scale-out backup repositories:
Put extents to the Maintenance mode
Evacuate backups from extents
Maintenance Mode
In some cases, you may want to perform service actions with extents of the scale-out backup repository. For example, you need to upgrade the backup repository server and add more memory to it. Or you want to replace a storage device backing the extent and need to relocate backup files. Before you start service actions, you must put the extent to the Maintenance mode.
An extent in the Maintenance mode operates with the limited functionality:
Veeam Backup & Replication does not start new tasks targeted at this extent.
You cannot restore VM data from backup files residing on the extent. You also cannot restore VM data from backup files residing on other extents if a part of the backup chain resides on the extent in the Maintenance mode.
When you switch the Maintenance mode, Veeam Backup & Replication launches the Repository Maintenance job. The Repository Maintenance job checks the status of jobs and tasks targeted at the extent and puts the extent to one of the following modes:
If no tasks using the extent are currently running, the job puts the extent to the Maintenance mode immediately.
If the extent is busy with any task, for example, a backup job, the job puts the extent to the Maintenance pending state and waits for the task to complete. When the task is complete, the extent is put to the Maintenance mode.
Backup Files Evacuation
If you want to exclude an extent from the scale-out backup repository, you first need to evacuate backup files from this extent. When you evacuate backups, Veeam Backup & Replication moves backup files from the extent to other extents that belong to the same scale-out backup repository. As a result, the backup chains remain consistent and you can work with them in a usual way.
The extent must be put to the Maintenance mode before you evacuate backups from it. If the extent is in the normal operational mode, the Evacuate option will not be available for this extent.
When selecting the target extent for evacuated files, Veeam Backup & Replication attempts to keep to the backup placement settings specified for remaining extents. For example, you have 3 extents in the scale-out backup repository with the following backup file placement settings:
On Extent 1, full backup files are stored.
On Extent 2 and Extent 3, incremental backup files are stored.
If you evacuate backup files from Extent 2, Veeam Backup & Replication will relocate them to Extent 3.
Backup Repositories with Rotated Drives
You can configure a backup repository to use rotated drives. This scenario can be helpful if you want to store backups on several external hard drives (for example, USB or eSATA) and plan to regularly swap these drives between different locations.
To use rotated drives, you must enable the This repository is backed up by rotated hard drives option in the advanced settings of the backup repository. When this option is enabled, Veeam Backup & Replication recognizes the backup target as a backup repository with rotated drives and uses a specific algorithm to make sure that the backup chain created on these drives is not broken.
Microsoft Windows Backup Repository
A job targeted at a backup repository with rotated drives is performed in the following way:
Veeam Backup & Replication creates a regular backup chain on the currently attached drive.
When a new job session starts, Veeam Backup & Replication checks if the backup chain on the currently attached drive is consistent. The consistent backup chain must contain a full backup and all incremental backups that have been produced by the job. This requirement applies to all types of backup chains: forever forward incremental, forward incremental and reverse incremental.
If external drives have been swapped, and the full backup or any incremental backups are missing from the currently attached drive, Veeam Backup & Replication behaves in the following way:
[For backup jobs] Veeam Backup & Replication starts the backup chain anew. It creates a new full backup file on the drive, and this full backup is used as a starting point for subsequent incremental backups.
[For backup copy jobs] If the attached drive is empty, Veeam Backup & Replication creates a full backup on it. If there is a backup chain on the drive, Veeam Backup & Replication creates a new incremental backup and adds it to the backup chain. The latest incremental backup existing in the backup chain is used as a starting point for the new incremental backup.
[For external drives attached to Microsoft Windows servers] Veeam Backup & Replication checks the retention policy set for the job. If some backup files in the backup chain are outdated, Veeam Backup & Replication removes them from the backup chain.
When you swap drives again, Veeam Backup & Replication behaves in the following way:
[For backup jobs] Veeam Backup & Replication checks the backup chain for consistency and creates a new full backup.
[For backup copy jobs] If the attached drive is empty, Veeam Backup & Replication creates a full backup on it. If there is a backup chain on the drive, Veeam Backup & Replication creates a new incremental backup and adds it to the backup chain. The latest incremental backup existing in the backup chain is used as a starting point for the new incremental backup.
When you specify retention settings for a job targeted at a backup repository with rotated drives, you must define the total number of restore points that you want to retain on all drives in the set. For example, if you set retention to 14, the job will keep the total of 14 restore points across all drives.
Drive letters for external drives may change when you add new volumes or storage hardware such as CD-ROM on the server. On Microsoft Windows backup repositories, Veeam Backup & Replication can keep track of drives and detect them even if the drive letter changes.
To detect a drive correctly, Veeam Backup & Replication must have a record about it in the configuration database. Consider the following requirements:
When you insert a drive for the first time, the drive is not registered in the configuration database. Such drive must have the same letter as the one specified in the Path to folder field in the backup repository settings.
If the drive has some other letter, Veeam Backup & Replication will not be able to detect and use it.
When you insert a drive that has already been used and has some restore points on it, the drive is already registered in the configuration database. Veeam Backup & Replication will be able to detect and use it, even if the drive letter changes.
Linux and Shared Folder Backup Repository
If you use a Linux server or CIFS share as a backup repository with rotated drives, Veeam Backup & Replication employs a “cropped” mechanism of work with rotated drives.
Veeam Backup & Replication keeps information only about the latest backup chain in the configuration database. Information about previous backup chains is removed from the database. For this reason, the retention policy set for the job may not work as expected.
A job targeted at a backup repository with rotated drives is performed in the following way:
During the first run of the job, Veeam Backup & Replication creates a regular backup full backup on the drive that is attached to the backup repository server.
During the next job session, Veeam Backup & Replication checks if the current backup chain on the attached drive is consistent. The consistent backup chain must contain a full backup and all incremental backups subsequent to it. This requirement applies to all types of backup chains: forever forward incremental, forward incremental and reverse incremental.
If the current backup chain is consistent, Veeam Backup & Replication adds a new restore point to the backup chain.
If external drives have been swapped, and the current backup chain is not consistent,
Veeam Backup & Replication always starts a new backup chain (even if restore points from previous backup chains are available on the attached drive). Veeam Backup & Replication creates a new full backup file on the drive, and this full backup is used as a starting point for subsequent incremental backups.
As soon as Veeam Backup & Replication starts a new backup chain on the drive, it removes information about restore points from previous backup chains from the configuration database. Backup files corresponding to these previous restore points are not deleted, they remain on disk. This happens because Veeam Backup & Replication applies the retention policy only to the current backup chain, not to previous backup chains.
Limitations for Backup Repositories with Rotated Drives
Backup repositories with rotated drives have the following limitations:
You cannot store archive full backups (GFS backups) created with backup copy jobs in backup repositories with rotated drives.
You cannot store per-VM backup files in backup repositories with rotated drives.
Support for Deduplicating Storage Systems
For disk-to-disk backups, you can use a deduplicating storage system as a target.
Veeam Backup & Replication supports the following deduplicating storage appliances:
EMC Data Domain
ExaGrid
HPE StoreOnce
EMC Data Domain
You can use EMC Data Domain storage systems with Data Domain Boost (DD Boost) as backup repositories.
The DD Boost technology offers a set of features for advanced data processing:
Distributed Segment Processing
Advanced Load Balancing and Link Failover
Virtual Synthetics
Managed File Replication
Veeam Backup & Replication supports Distributed Segment Processing, Advanced Load Balancing, Link Failover and Virtual Synthetics. Managed File Replication is not supported.
In addition to these technologies, Veeam Backup & Replication supports in-flight data encryption and per storage unit streams.
Distributed Segment Processing
Distributed Segment Processing lets EMC Data Domain “distribute” the deduplication process and perform a part of data deduplication operations on the backup proxy side.
Without Distributed Segment Processing, EMC Data Domain performs deduplication on the EMC Data Domain storage system. The backup proxy sends unfiltered data blocks to EMC Data Domain over the network. Data segmentation, filtering and compression operations are performed on the target side, before data is written to disk.
With Distributed Segment Processing, operations on data segmentation, filtering and compression are performed on the backup proxy side. The backup proxy sends only unique data blocks to EMC Data Domain. As a result, the load on the network reduces and the network throughput improves.
Advanced Load Balancing and Link Failover
Advanced Load Balancing and Link Failover allow you to balance data transfer load and route VM data traffic to a working link in case of network outage problems.
Without Advanced Load Balancing, every backup server connects to Data Domain on a dedicated Ethernet link. Such configuration does not provide an ability to balance the data transfer load across the links. If a network error occurs during the data transfer process, the backup job fails and needs to be restarted.
Advanced Load Balancing allows you to aggregate several Ethernet links into one interface group. As a result, EMC Data Domain automatically balances the traffic load coming from several backup servers united in one group. If some link in the group goes down, EMC Data Domain automatically performs link failover, and the backup traffic is routed to a working link.
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