For devices initialized on UNIX operating system files, the dsync setting controls whether or not writes to those files are buffered. When the dsync setting is on, Adaptive Server opens a database device file using the UNIX dsync flag. The dsync flag ensures that writes to the device file occur directly on the physical storage media, and Adaptive Server can recover data on the device in the event of a system failure.
When dsync is off, writes to the device file may be buffered by the UNIX and Windows NT file systems, and the recovery of data on the device cannot be ensured. The dsync setting should be turned off only when data integrity is not required, or when the System Administrator requires performance and behavior similar to earlier Adaptive Server versions.
The dsync setting is ignored for
devices initialized on raw partitions, and for devices initialized
on Windows NT files. In both cases, writes to the database device
take place directly to the physical media.
