I have submitted a file with size 1 GB and I want to split this file in files with size 100MB. How can I do that from the command line.
I'm searching for a command like:
hadoop fs -split --bytes=100m /user/foo/one_gb_file.csv /user/foo/100_mb_file_1-11.csv
Is there a way to do that in HDFS?
In HDFS, we cannot expect all feature that are available in unix. Current version of hadoop fs utility doesn't provide this functionality. May be we can expect in future. you can raise a bug(improvement in apache Jira) for including this feature in hdfs.
For now you got to write your own implementation in Java.
Related
I am new to MariaDB and need to do below activity.
We are using MariaDB as datatbase and we need to read a txt file from ftp location. Then load into a table. This has to be scheduled to read the file on a regular interval.
After searching I got LOAD DATA INFILE to be used, but it has the limitation that, it can't be used in Events.
Any suggestions/samples on this would be great help.
Thanks
Nitin
You import it and read it using the local path, MariaDB does basic file support, in no case it supports FTP transactions
LOAD DATA can only read a "file". But maybe the OS can play games...
What Operating System? If the OS can hide the fact that FTP is under the covers, then LOAD DATA will be none the wiser.
I have Hortonworks system in place and want to copy file from a file system to Hadoop. What is the best way to do that?
try:
hadoop fs -put /your/local/file.pdf /your/hdfs/location
or
hadoop fs -copyFromLocal /your/local/file.pdf /your/hdfs/location
refer put command
I am new to Hadoop and HDFS. I believe my question is somewhat related to this post. Essentially, I am trying to create empty files of 10 GB size in HDFS. The truncate command fails as specifying file size larger than the existing file size seems forbidden. Under such circumstances, what are the alternatives? For example, in Linux systems, one can use "truncate" command to set arbitrary file size.
You can use TestDFSIO to create the file with the required size in HDFS directly.
Program TestDFSIO is packaged in jar file 'hadoop-mapreduce-client-jobclient-tests.jar'. This jar comes with the hadoop installation, locate this jar and provide the path of this jar in the below command.
hadoop jar <PATH_OF_JAR_hadoop-mapreduce-client-jobclient-tests.jar> TestDFSIO -write -nrFiles 1 -fileSize 10GB
where "nrFiles" is Number of files and "filesize" is each file size to be generated.
File will be generated at path /benchmarks/TestDFSIO/ in HDFS.
I want to open/create a file and write some data in it in hadoop environment. The distributed file system I am using is hdfs.
I want to do it in pseudo distributed mode. Is there any way I can do this. Please give the code.
I think this post fits to your problem :-)
Writing data to hadoop
Is there a tool that creates a diff of a file structure, perhaps based on an MD5 manifest. My goal is to send a package across the wire that contains new/updated files and a list of files to remove. It needs to copy over new/updated files and remove files that have been deleted on the source file structure?
You might try rsync. Depending on your needs, the command might be as simple as this:
rsync -az --del /path/to/master dup-site:/path/to/duplicate
Quoting from rsync's web site:
rsync is an open source utility that
provides fast incremental file
transfer. rsync is freely available
under the GNU General Public License
and is currently being maintained by
Wayne Davison.
Or, if you prefer wikipedia:
rsync is a software application for
Unix systems which synchronizes files
and directories from one location to
another while minimizing data transfer
using delta encoding when appropriate.
An important feature of rsync not
found in most similar
programs/protocols is that the
mirroring takes place with only one
transmission in each direction. rsync
can copy or display directory contents
and copy files, optionally using
compression and recursion.
#vfilby I'm the process of implementing something similar.
I've been using rsync for a while, but it gets funky when deploying to remote server with permission changes that are out of my control. With rsync you can choose to not include permissions, but they still endup being considered for some reason.
I'm now using git diff. This works very well for text files. Diff generates patches, rather then a MANIFEST that you have to include with your files. The nice thing about patches is that there is already an established framework for using and testing these patches before they're applied.
For example, with patch utility that comes standard on any *unix box, you can run the patch in dry-run mode. This will tell you if the patch that you're going to apply is actually going to apply before you run it. This helps you to make sure that the files that you're updating have not changed while you were preparing the patch.
If this is similar to what you're looking for, I can elaborate on my process.