hadoop.tmp.dir /tmp/hadoop-${user.name} A base for other temporary directories. hadoop.native.lib true Should native hadoop libraries, if present, be used. hadoop.http.filter.initializers A comma separated list of class names. Each class in the list must extend org.apache.hadoop.http.FilterInitializer. The corresponding Filter will be initialized. Then, the Filter will be applied to all user facing jsp and servlet web pages. The ordering of the list defines the ordering of the filters. hadoop.security.authorization false Is service-level authorization enabled? hadoop.logfile.size 10000000 The max size of each log file hadoop.logfile.count 10 The max number of log files io.file.buffer.size 4096 The size of buffer for use in sequence files. The size of this buffer should probably be a multiple of hardware page size (4096 on Intel x86), and it determines how much data is buffered during read and write operations. io.bytes.per.checksum 512 The number of bytes per checksum. Must not be larger than io.file.buffer.size. io.skip.checksum.errors false If true, when a checksum error is encountered while reading a sequence file, entries are skipped, instead of throwing an exception. io.compression.codecs org.apache.hadoop.io.compress.DefaultCodec,org.apache.hadoop.io.compress.GzipCodec,org.apache.hadoop.io.compress.BZip2Codec A list of the compression codec classes that can be used for compression/decompression. io.serializations org.apache.hadoop.io.serializer.WritableSerialization,org.apache.hadoop.io.serializer.avro.AvroSpecificSerialization,org.apache.hadoop.io.serializer.avro.AvroReflectSerialization,org.apache.hadoop.io.serializer.avro.AvroGenericSerialization A list of serialization classes that can be used for obtaining serializers and deserializers. io.seqfile.local.dir ${hadoop.tmp.dir}/io/local The local directory where sequence file stores intermediate data files during merge. May be a comma-separated list of directories on different devices in order to spread disk i/o. Directories that do not exist are ignored. io.map.index.skip 0 Number of index entries to skip between each entry. Zero by default. Setting this to values larger than zero can facilitate opening large MapFiles using less memory. fs.default.name file:/// The name of the default file system. A URI whose scheme and authority determine the FileSystem implementation. The uri's scheme determines the config property (fs.SCHEME.impl) naming the FileSystem implementation class. The uri's authority is used to determine the host, port, etc. for a filesystem. fs.trash.interval 0 Number of minutes between trash checkpoints. If zero, the trash feature is disabled. fs.file.impl org.apache.hadoop.fs.LocalFileSystem The FileSystem for file: uris. fs.hdfs.impl org.apache.hadoop.hdfs.DistributedFileSystem The FileSystem for hdfs: uris. fs.s3.impl org.apache.hadoop.fs.s3.S3FileSystem The FileSystem for s3: uris. fs.s3n.impl org.apache.hadoop.fs.s3native.NativeS3FileSystem The FileSystem for s3n: (Native S3) uris. fs.kfs.impl org.apache.hadoop.fs.kfs.KosmosFileSystem The FileSystem for kfs: uris. fs.hftp.impl org.apache.hadoop.hdfs.HftpFileSystem fs.hsftp.impl org.apache.hadoop.hdfs.HsftpFileSystem fs.ftp.impl org.apache.hadoop.fs.ftp.FTPFileSystem The FileSystem for ftp: uris. fs.ramfs.impl org.apache.hadoop.fs.InMemoryFileSystem The FileSystem for ramfs: uris. fs.har.impl org.apache.hadoop.fs.HarFileSystem The filesystem for Hadoop archives. fs.checkpoint.dir ${hadoop.tmp.dir}/dfs/namesecondary Determines where on the local filesystem the DFS secondary name node should store the temporary images to merge. If this is a comma-delimited list of directories then the image is replicated in all of the directories for redundancy. fs.checkpoint.edits.dir ${fs.checkpoint.dir} Determines where on the local filesystem the DFS secondary name node should store the temporary edits to merge. If this is a comma-delimited list of directoires then teh edits is replicated in all of the directoires for redundancy. Default value is same as fs.checkpoint.dir fs.checkpoint.period 3600 The number of seconds between two periodic checkpoints. fs.checkpoint.size 67108864 The size of the current edit log (in bytes) that triggers a periodic checkpoint even if the fs.checkpoint.period hasn't expired. fs.s3.block.size 67108864 Block size to use when writing files to S3. fs.s3.buffer.dir ${hadoop.tmp.dir}/s3 Determines where on the local filesystem the S3 filesystem should store files before sending them to S3 (or after retrieving them from S3). fs.s3.maxRetries 4 The maximum number of retries for reading or writing files to S3, before we signal failure to the application. fs.s3.sleepTimeSeconds 10 The number of seconds to sleep between each S3 retry. fs.automatic.close true By default, FileSystem instances are automatically closed at program exit using a JVM shutdown hook. Setting this property to false disables this behavior. This is an advanced option that should only be used by server applications requiring a more carefully orchestrated shutdown sequence. fs.s3n.block.size 67108864 Block size to use when reading files using the native S3 filesystem (s3n: URIs). local.cache.size 10737418240 The limit on the size of cache you want to keep, set by default to 10GB. This will act as a soft limit on the cache directory for out of band data. io.seqfile.compress.blocksize 1000000 The minimum block size for compression in block compressed SequenceFiles. io.seqfile.lazydecompress true Should values of block-compressed SequenceFiles be decompressed only when necessary. io.seqfile.sorter.recordlimit 1000000 The limit on number of records to be kept in memory in a spill in SequenceFiles.Sorter io.mapfile.bloom.size 1048576 The size of BloomFilter-s used in BloomMapFile. Each time this many keys is appended the next BloomFilter will be created (inside a DynamicBloomFilter). Larger values minimize the number of filters, which slightly increases the performance, but may waste too much space if the total number of keys is usually much smaller than this number. io.mapfile.bloom.error.rate 0.005 The rate of false positives in BloomFilter-s used in BloomMapFile. As this value decreases, the size of BloomFilter-s increases exponentially. This value is the probability of encountering false positives (default is 0.5%). hadoop.util.hash.type murmur The default implementation of Hash. Currently this can take one of the two values: 'murmur' to select MurmurHash and 'jenkins' to select JenkinsHash. ipc.client.idlethreshold 4000 Defines the threshold number of connections after which connections will be inspected for idleness. ipc.client.kill.max 10 Defines the maximum number of clients to disconnect in one go. ipc.client.connection.maxidletime 10000 The maximum time in msec after which a client will bring down the connection to the server. ipc.client.connect.max.retries 10 Indicates the number of retries a client will make to establish a server connection. ipc.server.listen.queue.size 128 Indicates the length of the listen queue for servers accepting client connections. ipc.server.tcpnodelay false Turn on/off Nagle's algorithm for the TCP socket connection on the server. Setting to true disables the algorithm and may decrease latency with a cost of more/smaller packets. ipc.client.tcpnodelay false Turn on/off Nagle's algorithm for the TCP socket connection on the client. Setting to true disables the algorithm and may decrease latency with a cost of more/smaller packets. webinterface.private.actions false If set to true, the web interfaces of JT and NN may contain actions, such as kill job, delete file, etc., that should not be exposed to public. Enable this option if the interfaces are only reachable by those who have the right authorization. hadoop.rpc.socket.factory.class.default org.apache.hadoop.net.StandardSocketFactory Default SocketFactory to use. This parameter is expected to be formatted as "package.FactoryClassName". hadoop.rpc.socket.factory.class.ClientProtocol SocketFactory to use to connect to a DFS. If null or empty, use hadoop.rpc.socket.class.default. This socket factory is also used by DFSClient to create sockets to DataNodes. hadoop.socks.server Address (host:port) of the SOCKS server to be used by the SocksSocketFactory. topology.node.switch.mapping.impl org.apache.hadoop.net.ScriptBasedMapping The default implementation of the DNSToSwitchMapping. It invokes a script specified in topology.script.file.name to resolve node names. If the value for topology.script.file.name is not set, the default value of DEFAULT_RACK is returned for all node names. topology.script.file.name The script name that should be invoked to resolve DNS names to NetworkTopology names. Example: the script would take host.foo.bar as an argument, and return /rack1 as the output. topology.script.number.args 100 The max number of args that the script configured with topology.script.file.name should be run with. Each arg is an IP address.