Upgrade from 1.6 directly to 2.x with downtime

Versions later that 1.6 have incompatible .snap and .xlog file formats: 1.6 files are supported during upgrade, but you won’t be able to return to 1.6 after running under 1.10 or 2.x for a while. A few configuration parameters are also renamed.

To perform a live upgrade from Tarantool 1.6 to a more recent version, like 2.8.4, 2.10.1 and such, it is necessary to take an intermediate step by upgrading 1.6 -> 1.10 -> 2.x. This is the only way to perform the upgrade without downtime.

However, a direct upgrade of a replica set from 1.6 to 2.x is also possible, but only with downtime.

Here is how to upgrade from Tarantool 1.6 directly to 2.x:

1. Stop all instances in the replica set.
2. Upgrade Tarantool version to 2.x on every instance.
3. Upgrade the corresponding instance files and applications, if needed.
4. Start all the instances with Tarantool 2.x.
5. Execute box.schema.upgrade() on the master.
6. Execute box.snapshot() on every node in the replica set.