Most of the default values for the piclient.ini buffering parameters are the same, so only parameters that are explicitly set need to be in both piclient.ini files.
The exception to this is the location of the buffer files, which is configured with the [APIBUFFER]FILEBUFPATH parameter. The default location of buffer files for the 32-bit PI API is 32-bit PI API dat directory (%PIHOME%\dat) and the default for the 64-bit PI API is 64-bit PI API dat directory (%PIHOME64%\dat). Therefore, when using both 32 and 64-bit PI APIs together, the FILEBUFPATH parameter must be set so that both instances will use the same location. For example, if a 64-bit interface was writing events to a buffer file in one directory, but the 32-bit API Buffer Server was attempting to read the events from the different file, then it will fail.
Note: When setting the FILEBUFPATH parameter, use the absolute path of the directory. Do not use a relative directory and do not use the %PIHOME% or %PIHOME64% environment variables.
For all versions of the PI API prior to 1.6.2 and for PI Buffer Subsystem versions prior to 3.4.380, the location of the buffer files was fixed to %PIHOME%\dat and was not configurable using FILEBUFPATH. Therefore, if these older versions of the PI API or PI Buffer Subsystem are used, the 64-bit PI API must be configured to set FILEBUFPATH to the folder referenced by %PIHOME%\dat.
OSIsoft recommends that you set FILEBUFPATH to the folder referenced by %PIHOME%\dat. In this way, buffer files will be in the expected location even when using the older versions of the 32-bit API Buffer Server or PI Buffer Subsystem, which do not support the FILEBUFPATH parameter.
Note: With PI API versions older than 1.6.2, PI Buffer Subsystem will not run if FILEBUFPATH is set in the 32-bit piclient.ini.
If the PI API version is 1.6.2 or later, and (if used) the PI Buffer Subsystem version is 3.4.380 or later, then it is possible for the FILEBUFPATH parameter to be something other than the %PIHOME%\dat directory. This could be useful if PI API is installed on a drive with relatively little free space. The buffer file can grow to 2GB, and so it may be desirable to configure the PI API to use a drive with more free space.
For information about additional piclient.ini parameters available to configure buffering, refer to the "Installing and Configuring Buffering" section.