|
|
The ability to keep an application available during an update is influenced by the factors described earlier in this section, such as the topology and the application update type. But the contributing factor is that your topology is compatible with the update type of the application. For example, when your update is a major upgrade, then have either a multiple cell or at least a multiple clusters topology.
Table 5-1 details which application update types can be performed on each topology while keeping the application available.
Table 5-1
| Multiple cells / multiple clusters | Single cell, single cluster | |
|---|---|---|
| Major release | OK | Not possible1 |
| Upgrade | OK | Possible (under certain circumstances and using special precautions)2 |
| Bugfix | OK | OK |
1 The major release update involves changes in the EIS tier. You cannot have different WebSphere application versions in one cluster accessing different data or back-end applications.
2 If your new application version can handle changes to the persistence layer gracefully.
Application availability depending on topologies and application update types
For more information, see 5.4.3, Update types: major release or upgrade and 5.4.4, Update type: bugfix release.
