private void preblow() {
    dirHolder.incrementTotalOplogSize(maxOplogSize);
    final OplogFile olf = getOLF();
    try {
      olf.raf.setLength(maxOplogSize);
      olf.raf.seek(0);
    } catch (IOException ignore) {
      // TODO: need a warning since this can impact perf.
      // I don't think I need any of this. If setLength throws then
      // the file is still ok.
    }
  }
A copy constructor used for creating a new oplog based on the previous Oplog. This constructor
is invoked only from the function switchOplog

@param oplogId integer identifying the new oplog
@param dirHolder The directory in which to create new Oplog
@param minSize Minimum oplog file size in bytes
geode-core/src/main/java/org/apache/geode/internal/cache/OverflowOplog.java