Set the file size in advance on GPFS

When started to use the buffer on GPFS we notices an increase
of metadata access times on GPFS. To try to reduce the number
of metadata updates we set the file size at creation time.

sf-buffer/include/BufferBinaryWriter.hpp

@@ -7,6 +7,9 @@
 
 class BufferBinaryWriter {
 
+    const size_t MAX_FILE_BYTES =
+            buffer_config::FILE_MOD * sizeof(BufferBinaryFormat);
+
     const std::string root_folder_;
     const std::string device_name_;
     std::string latest_filename_;