The Log File
The log file is where Broker Server initially stores the data that it needs to persist to disk. When a client publishes a guaranteed document, Broker Server commits the document to the log file before it returns control to the client. If the Broker Server cannot successfully write the document to the log, it returns an error so the publisher knows that the document was not received successfully.
Broker Server is able to write to the log file very quickly, in part, because the file is a fixed size and is preallocated. When the log file becomes full, Broker Server transfers data from the log file to a storage file to make room for new, incoming data.
You select the size of the log file when you install
Broker Server or create a
Broker Server with the server_config utility. You can modify the size and location of the log file after it has been created, but you must stop and restart the
Broker Server to do so. For procedures, see
Modifying the Size of the Log File.
The Software AG Installer automatically creates the log file in the Broker Server's data directory. If you use the server_config utility to create a Broker Server, you can place the log file elsewhere.
When you configure the size and location of the log file, keep the following points in mind:
The maximum size for a log file is 2 GB on 32-bit platforms and 8 GB (as a practical limit) on 64-bit platforms.
The log file for run-time data must be large enough to hold the largest document or batch of documents that a client will publish in a single transaction.
The larger the log file, the longer it will take
Broker Server to start. When
Broker Server starts, it reads the entire log and moves items to long-term storage.
Space for the entire log file is immediately allocated when you install or create the
Broker Server.
For optimal performance, place the log file on a fast device that is dedicated to the
Broker Server and is separate from the storage files.