非法捕鱼机

書名： Hadoop 2.x Administration Cookbook
作者名： Gurmukh Singh
本章字?jǐn)?shù)： 265字
更新時(shí)間： 2021-07-09 20:10:30

Recycle or trash bin configuration

There will also be cases where we need to restore an accidently deleted file or directory. This may be due to a user error or some archiving policy that cleans data periodically.

For such situations, we can configure the recycle bin so that the deleted files can be restored for a specified amount of time. In this recipe, we will see that this can be configured.

Getting ready

This recipe shows the steps needed to edit the configuration file and add new parameters to the file to enable trash in the Hadoop cluster.

How to do it...

ssh to Namenode and edit the core-site.xml file to add the following property to it:
```
<property>
<name>fs.trash.interval</name>
<value>10080</value>
</property>
```
The fs.trash.interval parameter defines the time in minutes after which the checkpoint will be deleted.

Restart the namenode daemon for the property to take effect:

$ hadoop-daemons.sh stop namenode
$ hadoop-daemons.sh start namenode

Once trash is enabled, delete any unimportant files, as shown in the following screenshot. You will see a different message--rather than saying deleted, it says moved to trash:

The deleted file can be restored by using the following command:

$ hadoop fs -cp /user/hadoop/.Trash/Current/input/new.txt /input/

How it works...

Any deleted data is moved to the .Trash directory under the home of the user who executed the command. Every time the check pointer runs, it creates a new checkpoint out of current and removes any checkpoints created more than fs.trash.interval minutes ago.

There's more...

In addition to the preceding method, there is a fs.trash.checkpoint.interval parameter that defines the number of minutes between checkpoints.

官术网_书友最值得收藏!

Hadoop 2.x Administration Cookbook

Recycle or trash bin configuration

Getting ready

How to do it...

How it works...

There's more...