TM1 Web and Applications server can be fully load-balanced / HA if configured as per (from 10.2 upwards) using this IBM Guide.
TM1 Admin server and TM1 server itself cannot be load-balanced or configured for HA, there will have to be some downtime / lost connections if one of the servers goes down.
The usual configurations for TM1 Server ‘high availability’ / fast restore are (2 TM1 servers, A & B):
- Using NAS to store data directory for A and have a stopped TM1 service on B pointing on the same data directory. If A goes down, we start B. Can cause issues with transaction log corruption (if A goes down in the middle of writing transaction log).
- ‘Warm’ backup from A to B : Scheduled copy of data directory from A to B (every hour or so). Open transaction logs will not be copied (locked by server process), so you need to run SaveDataAll before copy. Most commonly used scenario.
- TM1 Replication could be used to setup an online replica, but it’s not really reliable (I haven’t tested the latest versions) and I generally recommend against using TM1 replication in real projects
Overall, TM1 is not an OLTP / line-of-business system and users are quite tolerant for down-time of a few minutes / hours, so I’d rather not go the hard yards to set it up unless it’s really vital.