CEPH

• huge system, disigned for huge companies

GlusterFS

• easier than CEPH
• user space
• synchronous replication

Unison

• only 2 servers can be replicated
• works over SSH
• if file was modified on both servers between syncs, this file will not be in sync
• runs by cron

rsync

• one directional sync
• works over SSH
• runs by cron

Bittorrent sync (btsync)

• can sync huge directory
• doesn’t support linux permissions
• sophisticate sync mechanism, sync from nearest server

csync2

• it was devoloped for configuration files syncronization, it is not appropriate for directories more than 100 MB (according to official documentation)
• works without SSH
• runs by cron

elliptics

openstack swift

riak cs

LeoFS