Mammoth PostgreSQL Replicator uses a transaction log and async replication model that nearly eliminates extra load on your master server regardless of the number of slaves you have in production. It supports advanced features such as large object, role, and ACL (grant/revoke) replication. It also supports promotion and failover.
Skylable SX is a reliable, powerful, fully distributed cluster solution for your data storage needs. It can aggregate the disk space available on multiple servers and merge it into a single storage system. The cluster makes sure that your data is always replicated over multiple nodes (the exact number of copies is defined by the sysadmin) and synchronized. It has built-in support for deduplication, client-side encryption, on-the-fly compression, and much more.