Is there a way to find out where have the fragments of the file I have put in Hdfs gone? I mean the information as to where the file fragments stored in hdfs?
You can use the fsck command:
#> hadoop fsck /path/to/file -files -blocks -locations -racks
This lists for the file, the blocks and their associated metadata:
block name/ID
block length
block replication
locations (datanodeIp:port)
rack (prefix datanode ip's with the associated rack id)
For example:
/user/chris/file1.txt 123 bytes, 1 block(s): OK
0. blk_432678432632_3426532 len=123 repl=2 [/rack1/1.2.3.4:50010, /rack2/4.5.6.7:50010]
Related
I have a 1 GB file that I've put on HDFS. So, it would be broken into blocks and sent to different nodes in the cluster.
Is there any command to identify the exact size of the block of the file on a particular node?
Thanks.
You should use hdfs fsck command:
hdfs fsck /tmp/test.txt -files -blocks
This command will print information about all the blocks of which file consists:
/tmp/test.tar.gz 151937000 bytes, 2 block(s): OK
0. BP-739546456-192.168.20.1-1455713910789:blk_1073742021_1197 len=134217728 Live_repl=3
1. BP-739546456-192.168.20.1-1455713910789:blk_1073742022_1198 len=17719272 Live_repl=3
As you can see here is shown (len field in every row) actual used capacities of blocks.
Also there are many another useful features of hdfs fsck which you can see at the official Hadoop documentation page.
You can try:
hdfs getconf -confKey dfs.blocksize
I do not have reputation to comment.
Have a look at documentation page to set various properties, which covers
dfs.blocksize
Apart from configuration change, you can view actual size of file with
hadoop fs -ls fileNameWithPath
e.g.
hadoop fs -ls /user/edureka
output:
-rwxrwxrwx 1 edureka supergroup 391355 2014-09-30 12:29 /user/edureka/cust
I have 9 files each of size equal to BlockLength of the cluster , stored in hadoop .
I need to get the addresses of the datanodes where the files are present . The replication factor is 3 .
Is there any hadoop API to do this or any other possible way ?
The command to find the blocks and data node of a file is as given below
hadoop fsck /user/tom/part-00007 -files -blocks -racks
This displays the following result
/user/tom/part-00007 25582428 bytes, 1 block(s): OK
0. blk_-3724870485760122836_1035 len=25582428 repl=3 [/default-rack/10.251.43.2:50010,
/default-rack/10.251.27.178:50010, /default-rack/10.251.123.163:50010]
This specifies the datanodes where replicas are placed.
To use the java code, you can use the following class
org.apache.hadoop.hdfs.tools.DFSck
Using this method
doWork(final String[] args)
This will create a URI internally and print all the details using System.out.
I've a file on hdfs in the path 'test/test.txt' which is 1.3G
output of ls and du commands is:
hadoop fs -du test/test.txt -> 1379081672 test/test.txt
hadoop fs -ls test/test.txt ->
Found 1 items
-rw-r--r-- 3 testuser supergroup 1379081672 2014-05-06 20:27 test/test.txt
I want to run a mapreduce job on this file but when i start the mapreduce job on this file the job fails with the following error:
hadoop jar myjar.jar test.TestMapReduceDriver test output
14/05/29 16:42:03 WARN mapred.JobClient: Use GenericOptionsParser for parsing the
arguments. Applications should implement Tool for the same.
14/05/29 16:42:03 INFO input.FileInputFormat: Total input paths to process : 1
14/05/29 16:42:03 INFO mapred.JobClient: Running job: job_201405271131_9661
14/05/29 16:42:04 INFO mapred.JobClient: map 0% reduce 0%
14/05/29 16:42:17 INFO mapred.JobClient: Task Id : attempt_201405271131_9661_m_000004_0, Status : FAILED
java.io.IOException: Cannot obtain block length for LocatedBlock{BP-428948818-namenode-1392736828725:blk_-6790192659948575136_8493225; getBlockSize()=36904392; corrupt=false; offset=1342177280; locs=[datanode4:50010, datanode3:50010, datanode1:50010]}
at org.apache.hadoop.hdfs.DFSInputStream.readBlockLength(DFSInputStream.java:319)
at org.apache.hadoop.hdfs.DFSInputStream.fetchLocatedBlocksAndGetLastBlockLength(DFSInputStream.java:263)
at org.apache.hadoop.hdfs.DFSInputStream.openInfo(DFSInputStream.java:205)
at org.apache.hadoop.hdfs.DFSInputStream.<init>(DFSInputStream.java:198)
at org.apache.hadoop.hdfs.DFSClient.open(DFSClient.java:1117)
at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:249)
at org.apache.hadoop.hdfs.DistributedFileSystem.open(DistributedFileSystem.java:82)
at org.apache.hadoop.fs.FileSystem.open(FileSystem.java:746)
at org.apache.hadoop.mapreduce.lib.input.LineRecordReader.initialize(LineRecordReader.java:83)
at org.apache.hadoop.mapred.Ma`
i tried the following commands:
hadoop fs -cat test/test.txt gives the following error
cat: Cannot obtain block length for LocatedBlock{BP-428948818-10.17.56.16-1392736828725:blk_-6790192659948575136_8493225; getBlockSize()=36904392; corrupt=false; offset=1342177280; locs=[datanode3:50010, datanode1:50010, datanode4:50010]}
additionally i can't copy the file hadoop fs -cp test/test.txt tmp gives same error:
cp: Cannot obtain block length for LocatedBlock{BP-428948818-10.17.56.16-1392736828725:blk_-6790192659948575136_8493225; getBlockSize()=36904392; corrupt=false; offset=1342177280; locs=[datanode1:50010, datanode3:50010, datanode4:50010]}
output of the hdfs fsck /user/testuser/test/test.txt command:
Connecting to namenode via `http://namenode:50070`
FSCK started by testuser (auth:SIMPLE) from /10.17.56.16 for path
/user/testuser/test/test.txt at Thu May 29 17:00:44 EEST 2014
Status: HEALTHY
Total size: 0 B (Total open files size: 1379081672 B)
Total dirs: 0
Total files: 0 (Files currently being written: 1)
Total blocks (validated): 0 (Total open file blocks (not validated): 21)
Minimally replicated blocks: 0
Over-replicated blocks: 0
Under-replicated blocks: 0
Mis-replicated blocks: 0
Default replication factor: 3
Average block replication: 0.0
Corrupt blocks: 0
Missing replicas: 0
Number of data-nodes: 5
Number of racks: 1
FSCK ended at Thu May 29 17:00:44 EEST 2014 in 0 milliseconds
The filesystem under path /user/testuser/test/test.txt is HEALTHY
by the way i can see the content of the test.txt file from the web browser.
hadoop version is: Hadoop 2.0.0-cdh4.5.0
I got the same issue with you and I fixed it by the following steps.
There are some files that opened by flume but never closed (I am not sure about your reason).
You need to find the name of the opened files by the command:
hdfs fsck /directory/of/locked/files/ -files -openforwrite
You can try to recover files as command:
hdfs debug recoverLease -path <path-of-the-file> -retries 3
Or removing them by the command:
hdfs dfs -rmr <path-of-the-file>
I had the same error, but it was not due to the full disk problem, and I think the inverse, where there were files and blocks referenced by in the namenode that did not exist on any datanodes.
Thus, hdfs dfs -ls shows the files, but any operation on them fails, e.g. hdfs dfs -copyToLocal.
In my case, the hard part was isolating which files were listed but corrupted, as they existed in a tree having thousands of files. Oddly, hdfs fsck /path/to/files/ did not report any problems.
My solution was:
Isolate the location using copyToLocal which resulted in copyToLocal: Cannot obtain block length for LocatedBlock{BP-1918381527-10.74.2.77-1420822494740:blk_1120909039_47667041; getBlockSize()=1231; corrupt=false; offset=0; locs=[10.74.2.168:50010, 10.74.2.166:50010, 10.74.2.164:50010]} for several files
Get a list of the local directories using ls -1 > baddirs.out
get rid of the local files from the first copyToLocal
use for files incat baddirs.out;do echo $files; hdfs dfs -copyToLocal $files This will produce a list of directories checks, and errors where files are found.
get rid of the local files again, and now get lists of files from each affected subdirectory. Use that as input to a file-by-file copyToLocal, at which point you can echo each file as it's copied, then see where the error occurs.
use hdfs dfs -rm <file> for each file.
Confirm you got 'em all be removing all local files again, and using the original copyToLocal on the top level directory where you had problems.
A simple two hour process!
You are having some corrupted files with no blocks on datanode but an entry in namenode. Best to follow this:
https://stackoverflow.com/a/19216037/812906
According to this this may be produced by a full disk problem. I came across the same problem recently with an old file and checking my servers metrics it effectively was a full disk problem during the creation of that file. Most solutions just claim to delete the file and prey for it not happening again.
Is it possible to know filesize in blocks and its distribution over DataNodes in Hadoop?
Currently I am using:
frolo#A11:~/hadoop> $HADOOP_HOME/bin/hadoop dfs -stat "%b %o %r %n" /user/frolo/input/rmat-*
318339 67108864 1 rmat-10.0
392835957 67108864 1 rmat-20.0
Which does not show actual number of blocks created after uploading file to HDFS. And I dont know any way how to find out its distribution.
Thanks,
Alex
The %r in your stat command shows the replication factor of the queried file. If this is 1, it means there will only be only a single replica across the cluster for blocks belonging to this file. The hadoop fs -ls output also shows this value for listed files as one of its numeric columns, as replication factor is a per file FS attribute.
If you are looking to find where the blocks reside instead, you are looking for hdfs fsck (or hadoop fsck if using a dated release) instead. The below, for example, will let you see the list of block IDs and their respective set of resident locations, for any file:
hdfs fsck /user/frolo/input/rmat-10.0 -files -blocks -locations
In Hadoop fs how to lookup the block size for a particular file?
I was primarily interested in a command line, something like:
hadoop fs ... hdfs://fs1.data/...
But it looks like that does not exist. Is there a Java solution?
The fsck commands in the other answers list the blocks and allow you to see the number of blocks. However, to see the actual block size in bytes with no extra cruft do:
hadoop fs -stat %o /filename
Default block size is:
hdfs getconf -confKey dfs.blocksize
Details about units
The units for the block size are not documented in the hadoop fs -stat command, however, looking at the source line and the docs for the method it calls we can see it uses bytes and cannot report block sizes over about 9 exabytes.
The units for the hdfs getconf command may not be bytes. It returns whatever string is being used for dfs.blocksize in the configuration file. (This is seen in the source for the final function and its indirect caller)
Seems hadoop fs doesn't have options to do this.
But hadoop fsck could.
You can try this
$HADOOP_HOME/bin/hadoop fsck /path/to/file -files -blocks
I think it should be doable with:
hadoop fsck /filename -blocks
but I get Connection refused
Try to code below
path=hdfs://a/b/c
size=`hdfs dfs -count ${path} | awk '{print $3}'`
echo $size
For displaying the actual block size of the existing file within HDFS I used:
[pety#master1 ~]$ hdfs dfs -stat %o /tmp/testfile_64
67108864