Questions tagged [hdfs]

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

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How does placing data in various racks help to exploit the fact that intra-rack aggregated bandwidth>=inter-rack bandwidth?

GFS research paper snapshot it says that(my interpretation after reading research paper and its reviews) "inter rack bandwidth is lower than aggregated intra rack bandwidth(not sure what it means ...
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0 answers
20 views

hdfs + why not remove the corrupted blocks by automatic approach as cron job

we have Hadoop cluster with 376 data-node machines ( based on HDP version - 2.6.4 ) from time to time we can see XX number of corrupted blocks and to fix it we are performing the following: su hdfs ...
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89 views

hdfs + Missing replicas from fsck

we have Hadoop cluster , and we noticed that hdfs fsck gives the following results ..............Status: HEALTHY Total size: 58934628832 B Total dirs: 127002 Total files: 354214 Total ...
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103 views

HDFS + results from hdfs fsck / are diff from hdfs dfsadmin -report

we have hadoop cluster ( Ambari platform with HDP version - 2.6.4 ) and we performed verification step in order to understand if we have under replica blocks the first verification was with: su hdfs ...
1 vote
0 answers
70 views

HDFS + how to disable the "du -sk" verifcation on data node disks

We are using HDP cluster with 182 data node machines: HDP version - 2.6.4 Ambari version 2.6.1 We note the following behavior on the data nodes machines (its happens on all data-node machines and on ...
0 votes
0 answers
49 views

Right method to start namenode (HDFS)

I have a Hadoop Cluster over 2 nodes which i launch the namenode on master like so :    hdfs namenode -regular Is this command a good alternative to the hdfs --daemon start namenode ? and why my ...
0 votes
1 answer
33 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?
0 votes
1 answer
50 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?
0 votes
1 answer
40 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. ...
0 votes
1 answer
144 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 ...
0 votes
1 answer
242 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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1 vote
1 answer
839 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 ...
0 votes
1 answer
677 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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1 answer
175 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 ...
  • 451
0 votes
1 answer
1k 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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0 votes
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149 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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1 vote
0 answers
278 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 ...
0 votes
1 answer
588 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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1 vote
1 answer
190 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> ...
  • 111
1 vote
0 answers
100 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 ...
  • 111
1 vote
0 answers
170 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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0 votes
0 answers
39 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 ...
  • 451
0 votes
1 answer
407 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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1 vote
0 answers
44 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 ...
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4 votes
1 answer
19k 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 ...
0 votes
1 answer
1k 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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1 answer
120 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 ...
3 votes
0 answers
165 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 ...
1 vote
0 answers
18 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/...
2 votes
1 answer
2k 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 ...
2 votes
2 answers
1k 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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1 vote
0 answers
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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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0 votes
1 answer
728 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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1 vote
0 answers
812 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 ...
1 vote
0 answers
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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4 votes
2 answers
5k 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" ...
0 votes
1 answer
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....
1 vote
1 answer
71 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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4 votes
3 answers
20k 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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0 votes
1 answer
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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7 votes
2 answers
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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1 vote
0 answers
508 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 ...
3 votes
1 answer
817 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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1 vote
1 answer
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 ...
2 votes
0 answers
4k 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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3 votes
2 answers
4k 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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0 votes
2 answers
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 ...
2 votes
2 answers
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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4 votes
0 answers
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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13 votes
4 answers
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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