Network Deployment (Distributed operating systems), v8.0 > Applications > Service integration > Message stores > File stores

File store configuration attributes

Preserving the appropriate amount of space within log file, permanent store file, and temporary store file of a file store helps to ensure that operations and transactions behave predictably.
Data is first written to the log file sequentially, that is, new records are added to the end of the file. When the end of the log file is reached, old records at the beginning of the log file are overwritten by new records and this process repeats. Subsequently, data is written to the permanent store file and temporary store file. The exception is extremely short-lived data, which is only written to the log file.

The permanent store file and temporary store file each have a minimum reserved size and a maximum size. When they are created, the permanent and temporary store files consume their minimum reserved sizes, plus the size of the log. If the maximum size is set to a larger value than the minimum reserved size, the files grow up to the maximum size as required.

The default settings for the minimum and maximum sizes are most suitable if you are not using a dedicated disk for your file store because they protect the file store from other disk users, and also protect other disk users from the file store. The default settings are less appropriate if we have a disk that is dedicated to file store use, and in this case you might want to consider setting the maximum size set to unlimited.

If your file store is not on a dedicated disk, consider making the minimum and maximum sizes the same. Initially, the message store reserves the amount of space defined by the minimum setting. Therefore, if you use the same value for the maximum and minimum settings, this reduces the likelihood of other applications using disk space that you had intended for file store use. Setting the maximum size to a value other than unlimited reduces the likelihood of the file store using disk space that you had intended for use by other applications. Other applications can include, for example, the application server itself.

The default configuration for file store attributes is intended to be sufficient to be used in typical messaging workloads without further administration.

To improve the performance or availability of the log file or the two store files, you can configure the file store attributes to control where these files are placed. Similarly, you can configure the attributes that control the sizes of the log file and two store files, for example to handle workloads with a large number of active transactions, large messages, or a large volume of message data resident in the messaging engine.

This method of improving performance cannot be guaranteed on a compressing file system, for example, on an NT file system with the Compress this directory option selected. You should avoid configuring a file store to use a compressing file system for production use.

The following table shows the minimum and default values for file store attributes.

File store attributes and values. The first column lists the file store attributes. The second column provides the description of the attributes. The third column provides the minimum and default values of the attributes.

Attribute	Description	Minimum and default values
Log size	Size of the log file, in megabytes	Minimum: 10 MB Default: 100 MB
Minimum permanent store size	The minimum number of megabytes reserved by the permanent store file. The minimum store file size must always be at least as big as the log file.	Minimum: 0 Default: 200 MB
Maximum permanent store size	The maximum size in megabytes of the permanent store file. Consider making the maximum store file size double the size of the log file. The maximum size of the store file must always be larger than the log file. If the log file size is the same as the maximum store file size then the messaging engine will not start.	Minimum: 50 MB Default: 500 MB
Minimum temporary store size	The minimum number of megabytes reserved by the temporary store file. The minimum store file size must always be at least as big as the log file.	Minimum: 0 Default: 200 MB
Maximum temporary store size	The maximum size in megabytes of the temporary store file. Consider making the maximum store file size double the size of the log file. The maximum size of the store file must always be larger than the log file. If the log file size is the same as the maximum store file size then the messaging engine will not start.	Minimum: 50 MB Default: 500 MB
Unlimited permanent store size	Indicates whether the permanent store file is unlimited in size	Default: false
Unlimited temporary store size	Indicates whether the temporary store file is unlimited in size	Default: false
Log directory	Name of the directory that contains the log file	Default: ${USER_INSTALL_ROOT}/filestores/com.ibm.ws.sib/ <me_name>- <me_uuid>/log
Permanent store directory	Name of the directory that contains the permanent store file	Default: ${USER_INSTALL_ROOT}/filestores/com.ibm.ws.sib/ <me_name>- <me_uuid>/permanentStore
Temporary store directory	Name of the directory that contains the temporary store file	Default: ${USER_INSTALL_ROOT}/filestores/com.ibm.ws.sib/ <me_name>- <me_uuid>/temporaryStore

Modify file store configuration
File store [Settings] Concept topic

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