File Store: Configuration
Configuration Options Related Tasks Related Topics
Use this page to configure a disk-based file store for storing subsystem data, such as persistent JMS messages or Store-and-Forward messages.
Name Description Name
The name of this file store. This name must be unique within the WebLogic Server instance or its cluster.
Synchronous Write Policy
The disk write policy that determines how the file store writes data to disk.
This policy also affects the JMS file store's performance, scalability, and reliability. Oracle recommends
Direct-Write-With-Cachewhich tends to have the highest performance. The default value is
Direct-Write. The valid policy options are:
Direct I/O is supported on all platforms. When available, file stores in direct I/O mode automatically load the native I/O
wlfileiodriver. This option tends to out-perform
Cache-Flushand tend to be slower than
Direct-Write-With-Cache. This mode does not require a native store
wlfileiodriver, but performs faster when they are available.
Store records are written synchronously to primary files in the directory specified by the
Directoryattribute and asynchronously to a corresponding cache file in the
Cache Directory. The
Cache Directoryprovides information about disk space, locking, security, and performance implications. This mode requires a native store
wlfileiocodedriver. If the native driver cannot be loaded, then the write mode automatically switches to
Direct-Write. See CacheDirectory.
Transactions cannot complete until all of their writes have been flushed down to disk. This policy is reliable and scales well as the number of simultaneous users increases.Transactionally safe but tends to be a lower performer than direct-write policies.
Transactions are complete as soon as their writes are cached in memory, instead of waiting for the writes to successfully reach the disk. This is the fastest policy because write requests do not block waiting to be synchronized to disk, but, unlike other policies, is not transactionally safe in the event of operating system or hardware failures. Such failures can lead to duplicate or lost data/messages. This option does not require native store
wlfileiodrivers, but may run faster when they are available. Some non-WebLogic JMS vendors default to a policy that is equivalent to
When available, file stores load WebLogic
wlfileionative drivers, which can improve performance. These drivers are included with Windows, Solaris, Linux, HP-UX, and AIX WebLogic installations.
Certain older versions of Microsoft Windows may incorrectly report storage device synchronous write completion if the Windows default
Write Cache Enabledsetting is used. This violates the transactional semantics of transactional products (not specific to Oracle), including file stores configured with a
Direct-Write-With-Cachepolicy, as a system crash or power failure can lead to a loss or a duplication of records/messages. One of the visible symptoms is that this problem may manifest itself in high persistent message/transaction throughput exceeding the physical capabilities of your storage device. You can address the problem by applying a Microsoft supplied patch, disabling the Windows
Write Cache Enabledsetting, or by using a power-protected storage device. See http://support.microsoft.com/kb/281672 and http://support.microsoft.com/kb/332023.
NFS storage note: On some operating systems, native driver memory-mapping is incompatible with NFS when files are locked. Stores with synchronous write policies
Direct-Write-With-Cacheor Disabled, and WebLogic JMS paging stores enhance performance by using the native
wlfileiodriver to perform memory-map operating system calls. When a store detects an incompatibility between NFS, file locking, and memory mapping, it automatically downgrades to conventional read/write system calls instead of memory mapping. For best performance, Oracle recommends investigating alternative NFS client drivers, configuring a non-NFS storage location, or in controlled environments and at your own risk, disabling the file locks (See FileLockingEnabled). For more information, see "Tuning the WebLogic Persistent Store" in Performance and Tuning for Oracle WebLogic Server.
The server instances or migratable targets defined in the current domain that are candidates for hosting the file store.
In a clustered environment, a recommended best practice is to target a custom file store to the same migratable target as the migratable JMS service, so that a member server will not be a single point of failure. A file store can also be configured to automatically migrate from an unhealthy server instance to a healthy server instance with the help of the server health monitoring services.
The path name to the file system directory where the file store maintains its data files.
When targeting a file store to a migratable target, the store directory must be accessible from all candidate server members in the migratable target.
For highest availability, use either a SAN (Storage Area Network) or other reliable shared storage.
Use of NFS mounts is discouraged, but supported. Most NFS mounts are not transactionally safe by default, and, to ensure transactional correctness, need to be configured using your NFS vendor documentation in order to honor synchronous write requests.
Direct-Write-With-Cache, see CacheDirectory.
Additional O/S tuning may be required if the directory is hosted by Microsoft Windows, see SynchronousWritePolicy for details.
The name used by subsystems to refer to different stores on different servers using the same name.
For example, an EJB that uses the timer service may refer to its store using the logical name, and this name may be valid on multiple servers in the same cluster, even if each server has a store with a different physical name.
Multiple stores in the same domain or the same cluster may share the same logical name. However, a given logical name may not be assigned to more than one store on the same server.
The location of the cache directory for
Direct-Write-With-Cache, ignored for other policies.
Direct-Write-With-Cacheis specified as the
SynchronousWritePolicy, cache files are created in addition to primary files (see Directory for the location of primary files). If a cache directory location is specified, the cache file path is
CacheDirectory/WLStoreCache/StoreNameFileNum.DAT.cache. When specified, Oracle recommends using absolute paths, but if the directory location is a relative path, then
CacheDirectoryis created relative to the WebLogic Server instance's home directory. If "" or
Nullis specified, the
CacheDirectoryis located in the current operating system
tempdir as determined by the
java.io.tmpdirJava System property (JDK's default:
%TEMP%on Windows) and is
TempDirectory/WLStoreCache/DomainName/unique-id/ StoreNameFileNum.DAT.cache. The value of
java.io.tmpdirvaries between operating systems and configurations, and can be overridden by passing
-Djava.io.tmpdir=My_pathon the JVM command line.
Security: Some users may want to set specific directory permissions to limit access to the cache directory, especially if there are custom configured user access limitations on the primary directory. For a complete guide to WebLogic security, see "Securing a Production Environment for Oracle WebLogic Server."
Additional Disk Space Usage: Cache files consume the same amount of disk space as the primary store files that they mirror. See Directory for the location of primary store files.
Performance: For the best performance, a cache directory should be located in local storage instead of NAS/SAN (remote) storage, preferably in the operating system's
tempdirectory. Relative paths should be avoided, as relative paths are located based on the domain installation, which is typically on remote storage. It is safe to delete a cache directory while the store is not running, but this may slow down the next store boot.
Preventing Corruption and File Locking: Two same named stores must not be configured to share the same primary or cache directory. There are store file locking checks that are designed to detect such conflicts and prevent corruption by failing the store boot, but it is not recommended to depend on the file locking feature for correctness. See FileLockingEnabled.
Boot Recovery: Cache files are reused to speed up the File Store boot and recovery process, but only if the store's host WebLogic Server instance has been shut down cleanly prior to the current boot. For example, cache files are not re-used and are instead fully recreated: after a
kill -9, after an OS or JVM crash, or after an off-line change to the primary files, such as a store admin compaction. When cache files are recreated, a code>Warning log message 280102 is generated.
Fail-Over/Migration Recovery: A file store safely recovers its data without its cache directory. Therefore, a cache directory does not need to be copied or otherwise made accessible after a fail-over or migration, and similarly does not need to be placed in NAS/SAN storage. A
Warninglog message 280102, which is generated to indicate the need to recreate the cache on the new host system, can be ignored.
Cache File Cleanup: To prevent unused cache files from consuming disk space, test and developer environments should periodically delete cache files.
Minimum Window Buffer Size
The minimum amount of data, in bytes and rounded down to the nearest power of 2, mapped into the JVM's address space per primary store file. Applies to synchronous write policies
Disabled, but only when a native
wlfileiolibrary is loaded. See MaxWindowBufferSize.
Maximum Window Buffer Size
The maximum amount of data, in bytes and rounded down to the nearest power of 2, mapped into the JVM's address space per primary store file. Applies to synchronous write policies
Disabledbut only when the native
wlfileiolibrary is loaded.
A window buffer does not consume Java heap memory, but does consume off-heap (native) memory. If the store is unable to allocate the requested buffer size, it allocates smaller and smaller buffers until it reaches
MinWindowBufferSize, and then fails if cannot honor
Oracle recommends setting the max window buffer size to more than double the size of the largest write (multiple concurrently updated records may be combined into a single write), and greater than or equal to the file size, unless there are other constraints. 32-bit JVMs may impose a total limit of between 2 and 4GB for combined Java heap plus off-heap (native) memory usage.
See store attribute
AllocatedWindowBufferBytesto find out the actual allocated Window Buffer Size.
IO Buffer Size
The I/O buffer size, in bytes, automatically rounded down to the nearest power of 2.
Direct-Write-With-Cachepolicy when a native
wlfileiodriver is available,
IOBufferSizedescribes the maximum portion of a cache view that is passed to a system call. This portion does not consume off-heap (native) or Java heap memory.
IOBufferSizeis the size of a per store buffer which consumes off-heap (native) memory, where one buffer is allocated during run-time, but multiple buffers may be temporarily created during boot recovery.
When a native
wlfileiodriver is not available, the setting applies to off-heap (native) memory for all policies (including
For the best runtime performance, Oracle recommends setting
IOBufferSizeso that it is larger than the largest write (multiple concurrent store requests may be combined into a single write).
For the best boot recovery time performance of large stores, Oracle recommends setting
IOBufferSizeto at least 2 megabytes.
AllocatedIOBufferBytesto find out the actual allocated off-heap (native) memory amount. It is a multiple of
Cache-Flushpolicies, or zero.
Maximum File Size
The maximum file size, in bytes.
MaxFileSizevalue affects the number of files needed to accommodate a store of a particular size (number of files = store size/MaxFileSize rounded up).
A file store automatically reuses space freed by deleted records and automatically expands individual files up to
MaxFileSizeif there is not enough space for a new record. If there is no space left in exiting files for a new record, a store creates an additional file.
A small number of larger files is normally preferred over a large number of smaller files as each file allocates Window Buffer and file handles.
MaxFileSizeis larger than 2^24 *
MaxFileSizeis ignored, and the value becomes 2^24 *
BlockSize. The default
BlockSizeis 512, and 2^24 * 512 is 8 GB.
Enable File Locking
Determines whether OS file locking is used.
When file locking protection is enabled, a store boot fails if another store instance already has opened the store files. Do not disable this setting unless you have procedures in place to prevent multiple store instances from opening the same file. File locking is not required but helps prevent corruption in the event that two same-named file store instances attempt to operate in the same directories. This setting applies to both primary and cache files.
The smallest addressable block, in bytes, of a file. When a native
wlfileiodriver is available and the block size has not been configured by the user, the store selects the minimum OS specific value for unbuffered (direct) I/O, if it is within the range [512, 8192].
A file store's block size does not change once the file store creates its files. Changes to block size only take effect for new file stores or after the current files have been deleted. See "Tuning the Persistent Store" in Performance and Tuning for Oracle WebLogic Server.
The initial file size, in bytes.
InitialSizeto pre-allocate file space during a file store boot. If
MaxFileSize, a store creates multiple files (number of files =
A file store automatically reuses the space from deleted records and automatically expands a file if there is not enough space for a new write request.
InitialSizeto limit or prevent file expansions during runtime, as file expansion introduces temporary latencies that may be noticeable under rare circumstances.
Changes to initial size only take effect for new file stores, or after any current files have been deleted prior to restart.