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Timo
Gold ⭐️
February 20, 2024
Solved

HDFS DN is writing into root-vg after disk failure

Hey there, 

we're running a CDP PC Base Cluster in our datacenter. In the last months we saw serveral disks failing due to theire age. The Problem we had, is that, when a disk fails, HDFS DN and YARN NM creating directories in the root-vg of the node. During normal operations the DN has it directories on the grids (/grid/[0-16]/*).

Is there a parameter to prevent them of writing into the root-vg, when a grid points to the root-vg and not it's physical device under /dev/sd*?

Regards, 

Timo

ChethanYM
ChethanYMAnswer
Gold ⭐️
February 21, 2024

Hi @Timo ,

In Apache Hadoop, the directories where HDFS DataNodes and YARN NodeManagers store their data and logs are typically configured using the "dfs.datanode.data.dir" and "yarn.nodemanager.local-dirs" properties respectively.

To prevent HDFS DataNodes and YARN NodeManagers from writing data to the root-vg directory when disks fail, you should ensure that these properties are configured correctly to point to directories on the healthy disks or storage volumes.

-> Configure HDFS DataNode Data Directories:Set the "dfs.datanode.data.dir" property in "hdfs-site.xml" to specify the directories where HDFS DataNodes should store their data. Make sure to list the directories on the healthy disks or storage volumes.

-> Configure YARN NodeManager Local Directories:

Set the "yarn.nodemanager.local-dirs" property in "yarn-site.xml" to specify the directories where YARN NodeManagers should store their local data and logs. Again, ensure that these directories are on the healthy disks or storage volumes.

 

Regards,

Chethan YM

 

2 replies

ChethanYM
Gold ⭐️
ChethanYMAnswer
Gold ⭐️
February 21, 2024

Hi @Timo ,

In Apache Hadoop, the directories where HDFS DataNodes and YARN NodeManagers store their data and logs are typically configured using the "dfs.datanode.data.dir" and "yarn.nodemanager.local-dirs" properties respectively.

To prevent HDFS DataNodes and YARN NodeManagers from writing data to the root-vg directory when disks fail, you should ensure that these properties are configured correctly to point to directories on the healthy disks or storage volumes.

-> Configure HDFS DataNode Data Directories:Set the "dfs.datanode.data.dir" property in "hdfs-site.xml" to specify the directories where HDFS DataNodes should store their data. Make sure to list the directories on the healthy disks or storage volumes.

-> Configure YARN NodeManager Local Directories:

Set the "yarn.nodemanager.local-dirs" property in "yarn-site.xml" to specify the directories where YARN NodeManagers should store their local data and logs. Again, ensure that these directories are on the healthy disks or storage volumes.

 

Regards,

Chethan YM

 

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VidyaSargur
Community Manager
Community Manager
March 4, 2024

@Timo, Did the response assist in resolving your query? If it did, kindly mark the relevant reply as the solution, as it will aid others in locating the answer more easily in the future. 

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Regards, Vidya Sargur, Community Manager Was your question answered? Make sure to mark the answer as the accepted solution. If you find a reply useful, say thanks by clicking on the thumbs up button.