We use StoreOnce with Data Protector, the backup and recovery software. We also use it with Micro Focus products. Additionally, StoreOnce has similar functionalities to Data Domain.
They both offer NFS data store tools: Data Domain offers ETL and Catalyst Store, while StoreOnce has the equivalent in Catalyst Backup, similar to DD Boost in Data Domain.
StoreOnce helps with long-term data retention and disaster recovery strategies. It works similarly to Data Domain. It provides site-to-site replication, like StoreOnce to StoreOnce.
Additionally, it offers snapshot backup functionality, just like Data Domain. StoreOnce has built-in ransomware protection, with immutable backup options, similar to Data Domain's automated approach.
Finally, it integrates with Veeam, just like Data Domain. So, they're very similar products.
However, I have not used StoreOnce in a multi-site environment. We do have implementations with single-site, standalone deployments for many customers. But, I don't have any personal experience with using StoreOnce for multi-site replication, like StoreOnce to StoreOnce for disaster recovery purposes.
However, I do have experience with Data Domain's multi-site implementation. Its DR and ER functionalities were good, including the bandwidth-compressed layer application aspects.