question Re: What are the mount options for EXT4 for HDFS in Archives of Support Questions (Read Only)

What are the mount options for EXT4 for HDFS

diablo2 — Fri, 23 Dec 2016 15:24:09 GMT

In HDP DOC

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

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

Re: What are the mount options for EXT4 for HDFS

myoung — Sat, 24 Dec 2016 02:39:12 GMT

@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.

Re: What are the mount options for EXT4 for HDFS

ddharam — Sat, 24 Dec 2016 05:22:11 GMT

Hi @Huahua Wei

Please refer to following for fixing data loss:

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

Re: What are the mount options for EXT4 for HDFS

cstanca — Sat, 24 Dec 2016 13:05:58 GMT

@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.

Re: What are the mount options for EXT4 for HDFS

diablo2 — Mon, 26 Dec 2016 14:30:25 GMT

Thanks @Michael Young