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What are the mount options for EXT4 for HDFS

Rising Star

In HDP DOC

https://docs.hortonworks.com/HDPDocuments/HDP2/HDP-2.3.4/bk_cluster-planning-guide/content/ch_partit...

It is said

The ext4 file system may have potential data loss issues with default options because of the "delayed writes" feature

But not mentioned what options should use to mount EXT4 to avoid potential data loss

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Accepted Solutions

@Huahua Wei

You should be able to use just defaults,noatime as ext4 mount options. For the most part, data loss concerns revolve around improper shutdown of the servers (hard reboots, etc). Data loss is always a concern when a server is improperly shutdown.

The option data=ordered is the default and provides the best balance between performance and protection. If you need more data protection you can use data=journaled.

Out of the box, ext4 generally doesn't require as many tuning options as ext3 does. Most people tend to use defaults,noatime, but you can use defaults,noatime,data=journaled if you are concerned about data protection. Be aware there are likely performance impact.

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@Huahua Wei

You should be able to use just defaults,noatime as ext4 mount options. For the most part, data loss concerns revolve around improper shutdown of the servers (hard reboots, etc). Data loss is always a concern when a server is improperly shutdown.

The option data=ordered is the default and provides the best balance between performance and protection. If you need more data protection you can use data=journaled.

Out of the box, ext4 generally doesn't require as many tuning options as ext3 does. Most people tend to use defaults,noatime, but you can use defaults,noatime,data=journaled if you are concerned about data protection. Be aware there are likely performance impact.

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Rising Star

Contributor

Hi @Huahua Wei

Please refer to following for fixing data loss:

https://access.redhat.com/solutions/369383

@Huahua Wei

The statement in recommendation is related to the configuration what @Michael Young already mentioned. @ddharam is a different issue applicable to RHEL 6, good to know too.