The document discusses the implementation of a master-master replication system for syncing data between IoT devices and the cloud, highlighting user requirements and applicable protocols. It details challenges encountered with database choices, specifically with Tarantool, and the use of 6lbr-gateway for creating a mesh network. Additionally, it provides references and contact information for further inquiries.

1. Vasiliy Soshnikov, Sr. Software Engineer, Mail.Ru Group
Master-Master Replication and Scaling of an
Application between each of the IoT-Devices
and the Cloud

2. Agenda
• General idea
• An implementation
• Result

3. General idea

4. Everything are sync
App-server
IoT-device #1
IoT-device #N
Internet
World
More
IoT-devices
User

5. Requirements
• The system should sync data between each IoT-
devices
• The system should getting data from IoT-devices
• The system should sync data IoT-devices and the
cloud

6. User / App server
App server
HTTP / HTTPS / WebSockets Internet

7. Internet / IoT devices
App-server
IoT-device #1
IoT-device #2
Internet
World
?

8. Internet / IoT devices
App-server
IoT-device #1
IoT-device #2
Internet
World
MQTT

9. Internet / IoT devices
App-server
IoT-device #1
IoT-device #2
Internet
World
Even HTTP(S)

10. Internet / IoT devices
App-server
IoT-device #1
IoT-device #2
Internet
World
Some protocols

11. Internet / IoT devices
App-server
IoT-device #1
IoT-device #2
Internet
World
Async replication!

12. Async replication
• Replication - everywhere we have the same
dataset!
• Most of databases include Replication

13. Few words about databases

14. Databases
• Sqlite - no replication, no concurrent access
• Redis - only M-S replication
• MySQL and PgSQL - they to heavy for the small
device
• Tarantool - M-M replication, M-S replication
• Or any DB with M-M replication

15. An implementation

16. Problems with Tarantool

17. Problems with Tarantool
• Didn’t work under the armv7
• Didn’t work under the 32-bit (only 64-bit)

18. Solved!
• Use toolchain files for CMake.
• Don’t use unsigned and other types with specified
sizes; the libc has concrete types, like uint32_t.
• Port auto-test, you should expect that your auto-
test may be executed under a IoT-device.

19. IoT-device with 6LoWPAN / LoRaWAN

20. 6LoWPAN / LoRaWAN
IoT-device #1
IoT-device #N
World
More
IoT-devices
Getaway
Radio Waves

21. Gateway
• MIPS-based
• WAN-antenna on board
• 6lbr-gateway software installed
• 6lbr-gateway converts the radio-waves into the
IPv6-package and back.

22. 6lbr
Link: cetic.github.io/6lbr/
or tty

23. 6lbr-application
• 6lbr-application has TCP/IP stack
• 6lbr-application works with any tty
• 6lbr-application doesn’t work with MQTT. Sad!

24. Few words about 6lbr-application

25. 6lbr-application
• It has complex thread model
• It has complex memory model

26. Main loop of an application

27. What is next?
• 6lbr-gateway gives a possibility to create mesh-
network
• 6lbr-gateway and Tarantool tied via MQTT-broker.
• But! Tarantool doesn’t work with MQTT!

28. Tarantool / MQTT

29. MQTT-library
• libmosquitto - simple & portable & nice code!
• mosquitto - simple & fast MQTT-broker
Link: mosquitto.org/man/libmosquitto-3.html

31. Looping / Tarantool Fibers
Link: github.com/tarantool/mqtt

32. Example

33. 6lbr-gateway / MQTT / Async M-M Replication
Result

34. App-server
IoT-device #1
IoT-device #N
Internet
Async M-M replication
6lbr-gateway
MQTT over UART
MQTT over UART
User

35. Inside devices

36. Devices for prototyping
TODO the photo of GETAWAY
Gateway
Relay
Sensor
Relay
IoT-device

37. References
Tarantool
github.com/tarantool
6lbr
github.com/cetic/6lbr
Examples / My experiments
github.com/dedok/tarantool-on-edison

38. Questions & My contacts
facebook
facebook.com/vasiliy.soshnikov
e-mail
v.soshnikov@corp.mail.ru, dedok.mad@gmail.com
github
github.com/dedok