I've been doing research on how to setup a self host backup high availability solution using raspberry pi's. The biggest requirement is master to master replication and cross platform client support. One thing that is a big focus is that the raspbery pi's might not be on the same lan network, maybe ever at a different house. Should be able to remove a hard drive and plug in a new one when there is a failure. Key thing to backup solutions is more than one copy. I want high availability and encryption.

After some research I've determined what may be the best opensourced solutions right now.

Client syncing

  • nextcloud - prefered option so far
    • has mobile and desktop sync clients
    • uses mysql or postgres db
  • resilio
    • Seems to be easiest of any of the options, supports peer to peer on all devices, may be option 2 if database master to master replication on nextcloud doesn't work out. Only option of all the technologies that is not opensourced. Does not charge a subscription for consumers, pay once for family license.

Server peer to peer file sync:

  • resilio
    • costs money if you use their client applications and want to do specific sub folders, doesn't cost for a full peer to peer replication, has a mobile client
  • dat
    • new peer to peer file protocol similar to websockets
  • syncthing

Database master to master replication:

  • biggest area of concern mainly for nextcloud file sharing service


  • how to connect and setup a cluster would be interesting
    • vpn
    • telebit
    • aws vpc vpn connection
    • some other protocol


  • mysql - supposedly supports clustering
  • gundb - nosql db don't think it would work with nextcloud
  • cockroach db - enterprise tested, has mysql and postgres api support
  • yugabyte - postgres api supports clustering claims to be faster than cockroach db
  • postgres - least likely to work has a master - slave replication support

Access over internet:

  • telebit - may support load balancing with same configuration haven't tested
  • openvpn - connect to vpn to access a raspberry pi hosted backup solution for a location

Load balancing:

  • pending research - several options out there, may have to be external from local network
  • telebit suppposedly supports it
  • could pay for aws application load balancer and connect local machines to aws vpc via aws vpn
  • apache load balancer - doesn't guarantee health checks if one is down
  • nginx load balancer

Automated installation/startup - want to make as plug in and play as possible

  • dietpi - works on rock64 and raspberry pi
    • has some already supported software and can setup an bash script to run on first install to install third party software
  • startup service
    • besides starting up all other technologies put together, will send out an email with network information and a vpn cert to connect and debug a cluster instance having issues. Super easy using a bash script, just though I'd mention this.

Honorable mentions:

  • syncloud combines several of these technologies, but out of the box doesn't have master to master replication recomendations.
  • owncloud - nextcloud is a opensourced branch off of this
  • backupbuddy - no ios solution
  • syncthing - no ios solution, has a android solution

Are there alternative technologies that people here would recommend and why? Main concern seems to be the database master to master replication.