Rockwell Automation FactoryTalk Historian SE 3.0 H2H Interface User Guide - Manual (Page 116)

Buffering
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Maximum buffer file size (KB)
This is the maximum size of the buffer file ( [PIHOME]\DAT\APIBUF.DAT ). When Bufserv
cannot communicate with the Historian Server, it writes and appends data to this file. When
the buffer file reaches this maximum size, Bufserv discards data.
The default value is 2,000,000 KB, which is about 2 GB. The range is from 1 to 2,000,000.
Primary and Secondary Memory Buffer Size (Bytes)
This is a key parameter for buffering performance. The sum of these two memory buffer sizes
must be large enough to accommodate the data that an interface collects during a single scan.
A typical event with a Float32 point type requires about 25 bytes. If an interface writes data
to 5,000 points, it can potentially send 125,000 bytes (25 * 5000) of data in one scan. As a
result, the size of each memory buffer should be 62,500 bytes.
The default value of these memory buffers is 32,768 bytes. Rockwell Automation
recommends that these two memory buffer sizes should be increased to the maximum of
2000000 for the best buffering performance.
Send rate (milliseconds)
Send rate is the time in milliseconds that Bufserv waits between sending up to the Maximum
transfer objects (described below) to the Historian Server. The default value is 100. The valid
range is 0 to 2,000,000.
Maximum transfer objects
Maximum transfer objects is the maximum number of events that Bufserv sends between
each Send rate pause. The default value is 500. The valid range is 1 to 2,000,000.
Buffered Servers
The Buffered Servers page allows you to define the Historian Servers or Historian Collective
that the buffering application writes data.
PIBufss
PIBufss buffers data only to a single Historian Server or a Historian Collective. Select the
Historian Server or the Historian Collective from the Buffering to collective/server drop down
list box.
The following screen shows that PIBufss is configured to write data to a standalone Historian
Server named
starlight . Notice that the Replicate data to all collective member nodes
check box is disabled because this Historian Server is not part of a collective. (PIBufss
automatically detects whether a Historian Server is part of a collective.)