WebLogic Server Configuration Reference
SynchronousWritePolicy=( "Disabled" | "Cache-Flush" | "Direct-Write" )
A user-defined policy that determines how the JMS file store writes data to disk. This policy also affects the JMS file store's performance, scalability, and reliability. The valid policy options are:
Disabled - Transactions are complete as soon as their writes are cached in memory, instead of waiting for the writes to successfully reach the disk. This policy is the fastest, but the least reliable (that is, transactionally safe). It can be more than 100 times faster than the other policies, but power outages or operating system failures can cause lost and/or duplicate messages.
Direct-Write - File store writes are written directly to disk. This policy is supported on Solaris, HP-UX, and Windows. If this policy is set on an unsupported platform, the file store automatically uses the Cache-Flush policy instead.
Warning! Although the use of the Direct-Write policy is transactionally reliable on Solaris and HP systems, Windows systems may leave transaction data in the on-disk cache without writing it to disk immediately. This is not considered to be transactionally reliable, since a power failure can cause loss of on-disk cache data-- possibly resulting in lost and/or duplicate messages. For reliable writes using Direct-Write on Windows, either disable all write caching for the disk (enabled by default), or use a disk with a battery-backed cache. Some file systems, however, do not allow this value to be changed (for example, a RAID system that has a reliable cache).