Technical Details

Overview

Synctus links company branch offices together in a manner that works faster than a VPN for shared file access. It does this using a file replication system with the following features:

• Multi-master (many writers): make changes from any office.
• Real-time replication: files are synchronised when they are closed.
• Guaranteed conflict-free: locks ensure that conflicts never occur.
• Robust: in the face of connectivity failures, access is still possible from any office. Changes to files can also be made from any office where this doesn’t break the conflict-free guarantee.
• Configuration and maintenance free: appliances ship ready to use with no technical expertise required.

Synctus is sold as a set of turnkey hardware appliances, one for each office. Each appliance needs only a power connection and a network connection. All you need to do is plug in and turn on.

More detailed technical information follows.

Automatic Networking

Each appliance comes preconfigured with an identity defined by an SSL certificate and private key, ensuring that data stored on it is kept private.

Turn an appliance on and it automatically configures itself using DHCP. Once it has established an Internet connection, it locates and establishes a DTLS (SSL) connection with each of the other appliances in its set—even when appliances are behind NAT.

In order to make installation as simple as possible, this is all done without any configuration or intervention required by an administrator.

File Replication

Each appliance presents a standard (SMB/CIFS) file share to its LAN using Samba, presenting a replicated copy of the directory tree and of files contained within it.

When a file is modified and closed, or a modification is made to the tree, the change is automatically replicated to every other appliance.

Locking & Coherence

Each file has a corresponding lock. Each lock can be present on only one appliance at once. This means that two people at different offices cannot open the same file at once, just the same as if they were in a single office.

When a file is updated, its lock is not transferred to another office until that office has replicated to the latest version of the file. This way, only the latest version of the file is presented at each office. This stops any synchronisation conflicts from arising.

Resiliance to Network Failure

A Synctus appliance continues to operate even if connections to the Internet or to other appliances are down. In this situation locks cannot be transferred, but operation can continue for locks that are already held.

Locks are typically held where they were last used. This means that users will often find that they can continue to edit files that they usually work on, despite any loss of connectivity.

An administrator can also access a special hidden share to read all files regardless of where the locks are. When a connection is down, this can be used for manual intervention if required.