Deduplication appliances are optimized for write operations. However, random read I/O suffers from re-hydration processes required during restores (except appliances with a landing zone). For this reason we recommend to use inline deduplication appliances only as secondary targets, where parameters like price per GB are more important than restore performance.
As a storage-agnostic product, Veeam Backup & Replication can use any deduplication appliance as a repository in different use cases: primary backup repository (not recommended), backup copy repository, and Virtual Tape Library (VTL) container.
In general there are two types of deduplication appliances: Integrated and non-integrated.
Integrated appliances do use integrated ways of transporting backup data, like special protocols as
Catalyst or they integrate the Veeam Data Mover service directly in their appliance.
Always use active full backup to avoid synthetic operations. This is mandatory for non-integrated appliances. For integrated appliances, it is usually also the best way to go. The downside of active fulls is the need to transport the entire amount of virtual machines on a weekly/monthly basis. This can lead to long snapshot commit, so this mode needs to be planned carefully.
Also, consider that Instant VM Recovery might not be as fast as expected – unless the deduplication appliance offers a fast non deduplicated area for the most recent restore points (such as ExaGrid).
Veeam Backup Copy Jobs (except StoreOnce Catalyst Copy jobs) between two deduplication appliances de-hydrate the data. That leads to negative performance impact.
When using non-integrated appliances, synthethic operations should be avoided and Active Fulls for Backup Copy jobs should be used.
If one of the integrated appliances is used, synthetic operations will be performed on the appliance itself, so they will require minimal additional time and lower I/O.
Deduplication appliances used as VTLs combine the worst characteristics of two worlds. Limited restore options and bad performance. Only do that if there is a good reason (e.g. the appliance is already available with a WORM VTL license).