Veeam Agent for Microsoft Windows provides mechanisms of data compression and deduplication. Data compression and deduplication let you decrease traffic going over the network and disk space required for storing backup files.
Data compression decreases the size of created backups but affects duration of the backup procedure. Veeam Agent for Microsoft Windows allows you to select one of the following compression levels:
- None compression level is recommended if you plan to store backup files on storage devices that support hardware compression and deduplication.
- Dedupe-friendly is an optimized compression level for very low CPU usage. You can select this compression level if you want to decrease the load on the CPU of the Veeam Agent computer.
- Optimal is the recommended compression level. It provides the best ratio between size of the backup file and time of the backup procedure.
- High compression level provides additional 10% compression ratio over the Optimal level at the cost of about 10x higher CPU usage.
- Extreme compression provides the smallest size of the backup file but reduces the backup performance. We recommend that you use the extreme compression level only on Veeam Agent computers with modern multi-core CPUs (6 cores recommended).
You can change data compression settings for existing backup jobs. New settings will not have any effect on previously created backup files in the backup chain. They will be applied to new backup files created after the settings were changed.
Compression settings are changed on the fly. You do not need to create a new full backup to use new settings — Veeam Agent for Microsoft Windows will automatically apply the new compression level to newly created backup files.
Depending on the type of storage you select as a backup target, Veeam Agent for Microsoft Windows uses data blocks of different size, which optimizes the size of a backup file and job performance. You can choose one of the following storage optimization options:
- The Local target (16 TB + backup files) option is recommended for backup jobs that can produce very large full backup files — larger than 16 TB. With this option selected, Veeam Agent for Microsoft Windows uses data block size of 4096 KB.
Large data blocks produce a smaller metadata table that requires less memory and CPU resources to process. Note, however, that this storage optimization option will provide the largest size of incremental backup files.
- The Local target option is recommended for backup to SAN, DAS or local storage. With this option selected, Veeam Agent for Microsoft Windows uses data block size of 1024 KB.
The SAN identifies larger blocks of data and therefore can process large amounts of data at a time. This option provides the fastest backup job performance.
- The LAN target option is recommended for backup to NAS and onsite backup. With this option selected, Veeam Agent for Microsoft Windows uses data block size of 512 KB. This option reduces the size of an incremental backup file because of reduced data block sizes.
- The WAN target option is recommended if you plan to use WAN for offsite backup. With this option selected, Veeam Agent for Microsoft Windows uses data block size of 256 KB. This results in the smallest size of backup files, allowing you to reduce the amount of traffic over WAN.
Because of Microsoft OneDrive limitations, a larger number of backed-up data blocks results in lower write speed on a Microsoft OneDrive storage. As a result, it is not recommended to use data block size of less than 1024 KB for the backup job targeted at Microsoft OneDrive (as long as your network connection bandwidth allows you to transfer larger amounts of incremental backup data over the internet).
To apply new storage optimization settings, you must create an active full backup after you change storage optimization settings. Veeam Agent for Microsoft Windows will use the new block size for the active full backup and subsequent backup files in the backup chain.