hadoop core-default.xml配置文件

name	value	description
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.group.mapping	org.apache.hadoop.security.ShellBasedUnixGroupsMapping	Class for user to group mapping (get groups for a given user)
hadoop.security.authorization	false	Is service-level authorization enabled?
hadoop.security.authentication	simple	Possible values are simple (no authentication), and kerberos
hadoop.security.token.service.use_ip	true	Controls whether tokens always use IP addresses. DNS changes will not be detected if this option is enabled. Existing client connections that break will always reconnect to the IP of the original host. New clients will connect to the host's new IP but fail to locate a token. Disabling this option will allow existing and new clients to detect an IP change and continue to locate the new host's token.
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	A list of serialization classes that can be used for obtaining serializers and deserializers.
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.webhdfs.impl	org.apache.hadoop.hdfs.web.WebHdfsFileSystem
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.har.impl.disable.cache	true	Don't cache 'har' filesystem instances.
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.
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.
hadoop.security.uid.cache.secs	14400	NativeIO maintains a cache from UID to UserName. This is the timeout for an entry in that cache.