This topic describes some considerations and actions that you can
take to move the transaction logs for an application server to another server.
Why and when to perform this task
To move transaction logs from one application server to another,
consider the following steps:
Steps for this task
- Move all the transaction log files for the application server.
The transaction log directory for each server contains
a number of files and subdirectories. When moving transaction logs from one
server to another you must move all of the files and subdirectories together
as a single unit; otherwise recovery may not complete resulting in data inconsistency.
- For a server configuration where there are no distributed transactions,
move the transaction logs to any server that has access to the same resource
managers. For a single server or network-deployed server configuration
where it is known there are no distributed transactions present in the logs,
the transaction logs can be moved to any server (on any node) that has access
to the same resource managers as the original server. For example, the server
needs communication and valid security access to databases or message queues.
All
the transaction log files for the original server need to be moved to a directory
accessible by the new server. This can be accomplished by either renaming
the transaction log directory or copying all thecontents to the new server's
transaction log directory before starting the new server.
Note: To
complete transaction recovery, the application server uses the resource manager
configuration information in the transaction logs. However, for the application
server to continue to do new work with the same resource managers, the server
must have an appropriate resource manager configuration (as for the original
server).
- For a network-deployed server configuration where there are distributed
transactions, move the transaction logs to a server that has the same name
and host IP address, and access to the same resource managers. For
a network-deployed server configuration, when it is known there are distributed
transactions present in the logs, there are more restrictions. Distributed
transactions that access multiple servers log information about each server
involved in the transaction. This information includes the server name and
the IP address of the machine on which the server is running. When recovery
is taking place on server restart, the server uses this information to contact
the distributed servers and similarly, the distributed servers try to contact
the server with the same original name. So, if a server fails and the logs
need to the recovered on an alternative server, that alternative server needs
to have the same name and host IP address as the original server. The alternative
server also needs to have access to the same resource managers as the original
server. For example, the server needs communication and valid security access
to databases or message queues.
Note: All servers within a cell
must have unique names.
Note: To complete transaction recovery,
the application server uses the resource manager configuration information
in the transaction logs. However, for the application server to continue to
do new work with the same resource managers, the server must have an appropriate
resource manager configuration (as for the original server).