Performance or deduplication ratio is low when backing up to a deduplication enabled storage appliance from Veeam Backup & Replication.
Please note that following article does not pertain to ExaGrid Storage or EMC DataDomain. If you use either of these please see the corresponding articles:
If you are using ExaGrid Storage, please see https://www.veeam.com/kb2056
If you are using EMC DataDomain, please see https://www.veeam.com/kb1956
The default options within Veeam Backup & Replication are intended for non-deduplication storage.
It is advised to configure the job as following when backing up to a deduplication appliance:
- Use “Incremental”
- Uncheck “Enable synthetic fulls”
- Check “Perform active full backups periodically”
- Uncheck “Enable inline data deduplication”
- Change the Compression Level to “Dedupe-friendly”
- Change Optimize for to “Local target (16TB+ backup files)”
Forever Forward Incremental, Synthetic Full, and Reverse Incremental operations will perform poorly with deduplication devices because the backup files that have been written to the storage previously must be interacted with during these operations. The act of reading existing data on deduplication device is slow because each block requested must be rehydrated and uncompressed to be read. With DataDomain deduplication appliances, however, it is possible to leverage DataDomain's own mechanism of updating file blocks' metadata internally, and consequently achieve greater performance with Synthetic Full. New full backup files can then be created without physically moving data into the file, but rather by synthesizing them from the existing data.
The process of rehydration and uncompressing during read operations from the deduplication storage will also impact the performance of all restore operations.
Contact your storage vendor to inquire about further specific details to optimize Veeam Backup & Replication to work with their storage solution.
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