The following limitations and restrictions apply to using the dsync setting:
dsync is always set to true for the master device file. You cannot change the dsync setting for the master device. If you attempt to turn dsync off for the master device, Adaptive Server displays a warning message.
If you change a device file’s dsync setting using the sp_deviceattr procedure, you must restart Adaptive Server before the change takes effect.
When you upgrade from an Adaptive Server earlier than version 12.x, dsync is set to true for the master device file only. Use sp_deviceattr to change the dsync setting for any other device files.
Adaptive Server ignores the dsync setting for database devices stored on raw partitions. Writes to devices stored on raw partitions are always done directly to the physical media.
The directio and dsync parameters are mutually exclusive. If a device has dsync set to “true,” you cannot set directio to “true” for this device. To enable directio for a device, you must first reset dsync to “false.
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