Questions tagged [hdfs]

For questions regarding the Hadoop distributed file system (HDFS) which is part of the Apache Hadoop project.

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Hadoop HDFS copy from local

I want to do a hdfs copy from local, but I want to be sure that only files older than 1 hour are uploaded into hdfs. The files are beeing uploaded from clients via SFTP and i cant be 100% sure that ...
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13 views

Enable read-only HDFS filesystem in hostile cluster

Scenario A company's platform team maintains Spark clusters for data science teams to perform big data analysis on their data. The cluster comes with a pre-configured file system that allows read/...
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1answer
20 views

Hadoop recommissioning datanode

Do I need to delete all data from a datanode before recommissioning it, or it doesn't matter and the namenode will not pick stale data from the datanode?
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30 views

Change HDFS replication factor

I've changed replication factor from 3 to 2 for some directories with command: hdfs dfs -setrep -R 2 /path/to/dir but my HDFS free space still the same. Should I do something else to free my disks?
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29 views

HDFS. How to free 1 particular disk

I have cluster with 3 servers. 2 of them have 2 TB disks and another one have 500 Gb SSD. I am trying to use balancer, but I still get 70% of usage on 2TB disks and 99% on 500Gb due to non-dfs files. ...
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85 views

Hadoop Cluster Capacity Planning of Data Nodes for disks per data node

we are planing to build hadoop cluster with 12 data nodes machines when the replication factor is 3 and DataNode failed disk tolerance - 1 data nodes machines are include the disks for HDFS since we ...
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1answer
228 views

Optimal RAID configuration for EC2 instance store used for HDFS

I'm trying to determine if there is any practical advantage to configuring a RAID array on the instance store of a 3x d2.2xlarge instances being used for HDFS. Initially I planned to just mount each ...
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1answer
562 views

List all files in hdfs directory

Due to some error at one component, files in HDFS got accumulated and the number is huge i.e 2123516. I want to list all files and want to copy their name in one file but when I run the following ...
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1answer
404 views

AWS FSx for lustre with S3 vs EMR (with EMRFS) for spark jobs

We are currently using EMR for easy job submission for our spark jobs. Recently I came across the "FSx lustre + S3" solution that is being advertised as ideal for HPC situations. EMRFS however is also ...
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1answer
136 views

is it possible mix different RHEL OS version in hadoop cluster?

we are using the following HDP cluster with ambari , list of nodes and their RHEL version 3 masters machines ( with namenode & resource manager ) , installed on RHEL 7.2 312 DATA-NODES machines ...
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1answer
588 views

HDFS block deletion speed - cause, expectance, tuning?

I have a small (testing) HDFS cluster which I use as snapshot backup space for Flink. Flink creates and deletes roughly 1000 (small) files per second. The namenode seems to handle this without ...
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107 views

Any benefits of ZFS over EXT4 for data stream processing on top of HDFS?

I'm working on a data stream processing project in which i will be using Apache Flink and Apache Spark and I want to use HDFS for storage. The development and testing will be done on a single node ...
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148 views

HDFS NFS gateway read Input/output error

I have enabled the HDFS NFSv3 gateway on our HDFS cluster through official documentation. Everything works well except for one Ubuntu 16.04 server machine. The following is the kernel, mount and ...
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1answer
395 views

HDFS balancing , how to balanced hdfs data?

we have Hadoop version - 2.6.4 On the datanode machine we can see that hdfs data isn’t balanced On some disks we have different used size as sdb 11G and sdd 17G /dev/sdd 20G 3.0G 17G 15% /grid/...
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1answer
151 views

Hadoop: Failed to start backup node, bad state: DROP_UNTIL_NEXT_ROLL

I have created a small Hadoop cluster setup with 1 NameNode and 1 DataNode to get hands-on. below is my configuration files: Core-site.xml <property> <name>fs.defaultFS</name> ...
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98 views

Sample output of Rumen or Input to Gridmix

I want to see JobHistory logs, which can be fed as input to the Rumen. More specifically, I am interested in knowing input format for the Gridmix. I tried following two things for it: 1) I found ...
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159 views

ambari cluster + when need to set Block replication to 1

We get the following in Spark logs: java.io.IOException: Failed to replace a bad datanode on the existing pipeline due to no more good datanodes being available to try. (Nodes: current=[...
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37 views

Datanode machines disks size

is it important that ( workers ) datanode machines disks will be with the same size? for example we have ambari cluster with 3 workers machines ( datanode machines ) each datanode machine have 10 ...
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378 views

what is effected when running - hadoop namenode -format

we have amabri cluster ( version 2.6 ) with 24 workers machines we want to run following commands only on worker23 machine ( because problem on worker23 ) , dose these commands effected on all ...
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43 views

How to prevent arbitrary executable execution on hadoop cluster

I am involved with configuring a Hadoop cluster for complete auditability and security. I am new to the Hadoop ecosystem, but I have a decent idea of the basics. I have a few concerns for which I hope ...
4
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1answer
15k views

mount.nfs: mount system call failed

I am trying to mount hdfs on my local machine running Ubuntu using the following command :--- sudo mount -t nfs -o vers=3,proto=tcp,nolock 192.168.170.52:/ /mnt/hdfs_mount/ But I am getting this ...
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1answer
864 views

copying files in hdfs stalls

Have a 35 node cluster with a high number of blocks in it: ≈450K blocks per data node. After configuration change (which contained rack reassignments and NameNode Xmx increase) HDFS became a problem. ...
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94 views

how to install hadoop2.4.1 in windows with spark 2.0.0

i want to setup a cluster using hadoop in yarn mode..i want to use spark API for map-reduce and will use spark submit to deploy my applications..i want to work on cluster..can anyone help me how to ...
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159 views

How can I launch hdfs on Mesos without DC/OS?

From my understand DC/OS is a freemium managed service. Because I'd rather just have a raw Mesos implementation, I'd rather not be dependent on DC/OS and so I just want to know how to implement HDFS ...
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16 views

Need to set 000 permission to specific hdfs data block through commandline

I am trying to set the “000” permission to the specific block. I used below command to find the block information: su - hdfs -c "hdfs fsck -locations -files -blocks /user/rohit/...
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1answer
1k views

Running HDFS with only 1 data node - appending fails

I'm trying to test some services that require HDFS using Docker Compose. Since the services being tested, namenode, and data node(s) will all be running on the same physical machine (dev laptop), it ...
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2answers
914 views

Can HDFS be installed on ZFS or BTRFS hard disks?

I am new to hadoop and confused about how HDFS works with ZFS or BTRFS. Can physical drives be mounted using ZFS and then have HDFS installed on top of ZFS? Or can HDFS be installed directly?
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17 views

Is it possible to configure hdfs in a federation mode and in an HA mode in the same time?

I don't understand if it possible to configure HDFS in both modes in the same time. Does it make sense? Can somebody show a simple configuration of HDFS in both modes? (nameNode1, nameNode2, ...
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1answer
666 views

Why does DFSZKFailoverController kills Namenode process in hadoop?

I try to configure hadoop high availability cluster by following this tutorial: http://www.edureka.co/blog/how-to-set-up-hadoop-cluster-with-hdfs-high-availability/ When I follow that article I faces ...
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746 views

Zombie process blocking port when restarting Hadoop (Secondary) Namenode

I'm having weird issues with the Hadoop Namenode and Secondary Namenode. Our HDFS cluster runs smoothly most of the time. But every now and then, either the Primary Namenode freezes (crashing the ...
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2k views

HDFS performances on apache spark

I have several issues related to HDFS, that may have different roots. I'm posting as much information as I can, with the hope that I can get your opinion on at least some of them. Basically the cases ...
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1answer
4k views

Upload large files with curl without RAM cache.

I'm using curl to upload large files (from 5 to 20Gb) to HOOP based on HDFS (Hadoop Cluster) as follows: curl -f --data-binary "@$file" "$HOOP_HOST$UPLOAD_PATH?user.name=$HOOP_USER&op=create" ...
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1answer
3k views

Flume- Error Log while using FileChannel

I am using Flume flume-ng-1.5.0 ( with CDH 5.4) to collect logs from many Servers and Sink to HDFS Here is my configuration : #Define Source , Sinks, Channel collector.sources = avro collector....
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1answer
67 views

Viewing NxN network traffic in a distributed system

I have a Hadoop cluster set up, and I would like to view the network usage between all nodes in this cluster, i.e. if I have N nodes, I want to see NxN network connections so that I can view all ...
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3answers
19k views

Is there a way to grep gzipped content in hdfs without extracting it?

I'm looking for a way to zgrep hdfs files something like: hadoop fs -zcat hdfs://myfile.gz | grep "hi" or hadoop fs -cat hdfs://myfile.gz | zgrep "hi" it does not really work for me is there ...
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2k views

Hadoop: How to configure failover time for a datanode

I need to re-replicate blocks on my HDFS cluster in case of a datanode is failing. Actually, this appears to already happen after a period of maybe 10min. However, I want to decrease this time, but ...
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2answers
1k views

HBASE Space Used Started Climbing Rapidly

Update 4,215: After looking at space usage inside of hdfs, I see that .oldlogs is using a lot of space: 1485820612766 /hbase/.oldlogs So new questions: What is it? How do I clean it up? How do ...
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494 views

How to force HDFS to use LDAP user's UID

I have a cloudera cluster with HDFS and Hue services and I'm trying to unify the authentication using LDAP. I have my LDAP server running thanks to 389-ds (not sure if is the best way) and I can log ...
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1answer
784 views

Linux Network tuning to prevent tcp rcvpruned and backlogdrop?

My datanodes in my hbase cluster are triggering some tcp rcvpruned and backlog drops from time to time: It seems to be there are at least two angles to approach this at: Tune HBase/HDFS etc... so ...
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1answer
2k views

Rhadoop hdfs.init() Error

I recently installed CDH5.1.0 along with R 3.1.*, and I got rmr2, rJava, and rhdfs all installed properly. (along with the required packages and set the required environment variables) After some ...
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3k views

"The volume for a file has been externally altered ..." and setting file sizes on write to NFS from Windows

I have set up NFS access to HDFS. I can connect to the default root share from both Windows and Linux clients and all clients can read from the share. Writing from the Linux client is also ok. When ...
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2answers
3k views

Disable The Under Replicated Blocks Alert in Cloudera Manager

I have a single server Hbase cluster that I am only using as the sink end of HBase replication. Therefore I don't want to replicate any blocks within this cluster (since the source has replicated ...
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2answers
11k views

error while running any hadoop hdfs file system command

I am very new to hadoop and referring to the "hadoop for dummies" book. I have a VM with following specs: hadoop version 2.0.6-alpha bigtop os centos The problem is when I run any hdfs file system ...
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2answers
5k views

Unable to convert HDFS from non-HA to HA

Introduction Aim: Convert HDFS from non-HA to HA. Method: According to this documentation it should be possible to convert HFDS from non- to HA by implementing following configuration: /etc/hadoop/...
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0answers
2k views

java.lang.NullPointerException When Doing A Read in HDFS

I have had a 10 node HBase cluster up and running for the past 4 months. The cluster was setup on VMs in a corporate environment which I do not control, but everything has been working great...until ...
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4answers
8k views

In Hadoop, how to show current process of -copyFromLocal

I am still a newbie learner of Hadoop, and this time I was trying to process a 106GB file. I used -copyFromLocal to copy that big file to my Hadoop DFS, but since the file is big I have to wait for a ...
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0answers
68 views

When and how are initial directories created in HDFS

I have a Hadoop setup in which the configured HDFS umask is 027 instead of the default one. Some of the initially created directories have correct permissions (like tmp drwxrwxrwx) but others such as /...
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1answer
2k views

btrfs: Looking for experience on btrfs error modes on bad sectors / read errors / medium erros

While running a Hadoop cluster that uses HDFS (so data is already replicated 3x) we experience often issues with ext4 because some bad sectors (the filesystem is unable to read or write to them) ...
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1answer
474 views

Additional Storage Options for Hadoop HDFS Nodes

We have a small production Cloudera distribution Hadoop cluster(14 nodes, but growing). As we have expanded our usage of this cluster we have found that disk storage is our biggest blocker and ...
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2answers
2k views

Change existing linux user's uid in LDAP but hdfs seems does not recognize it

I have set up a hadoop 1.2.1 environment on centos 6. I also use nfs-proxy that mount ndfs to local file system so that I can access the files inside hdfs locally. It works perfectly until today, I ...