public static void createControlFile(FileSystem fs, long megaBytes, int numFiles, long seed)
throws Exception {
LOG.info("creating control file: " + megaBytes + " bytes, " + numFiles + " files");
Path controlFile = new Path(CONTROL_DIR, "files");
fs.delete(controlFile, true);
Random random = new Random(seed);
SequenceFile.Writer writer =
SequenceFile.createWriter(
fs, conf, controlFile, Text.class, LongWritable.class, CompressionType.NONE);
long totalSize = 0;
long maxSize = ((megaBytes / numFiles) * 2) + 1;
try {
while (totalSize < megaBytes) {
Text name = new Text(Long.toString(random.nextLong()));
long size = random.nextLong();
if (size < 0) size = -size;
size = size % maxSize;
// LOG.info(" adding: name="+name+" size="+size);
writer.append(name, new LongWritable(size));
totalSize += size;
}
} finally {
writer.close();
}
LOG.info("created control file for: " + totalSize + " bytes");
}
