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CM配置步骤：
Configuring HDFSTrash
The Hadooptrashfeature helps prevent accidental deletion of files and directories. Iftrashis enabled and
a file or directory is deleted using the Hadoop shell, the file is moved to the.Trashdirectory in
the user's home directory instead of being deleted. Deleted files are initially moved to theCurrentsub-directory of the.Trashdirectory,
and their original path is preserved. Iftrashcheckpointing is enabled, theCurrentdirectory is periodically
renamed using a timestamp. Files in.Trashare permanently removed after a user-configurable time delay.
Files and directories in thetrashcan be restored simply by moving them to a location outside the.Trashdirectory.
Configuring HDFSTrashUsing Cloudera Manager
Required
Role:
Enabling and DisablingTrash
-
Go to the HDFS service.
-
Click theConfigurationtab.
- Select.
- Select or deselect theUseTrashcheckbox.
If more than one role group applies to this configuration, edit the value for the appropriate role group. SeeModifying
Configuration Properties.
-
ClickSave Changesto commit the changes.
-
Restart the cluster and deploy the cluster client configuration.
Setting theTrashInterval
-
Go to the HDFS service.
-
Click theConfigurationtab.
- Select.
- Specify theFilesystemTrashIntervalproperty, which controls the number
of minutes after which atrashcheckpoint directory is deleted and the number of minutes betweentrashcheckpoints.
For example, to enabletrashso that deleted files are deleted after 24 hours, set the value of theFilesystemTrashIntervalproperty
to 1440.
Note:Thetrashinterval
is measured from the point at which the files are moved totrash, not from the last time the files were modified.
If more than one role group applies to this configuration, edit the value for the appropriate role group. SeeModifying
Configuration Properties.
-
ClickSave Changesto commit the changes.
- Restart all NameNodes.
command line：
Enabling Trash
The Hadoop trash feature helps prevent accidental deletion of files and directories. If trash is enabled and a file or directory is deleted using the Hadoop shell, the file is moved to the.Trashdirectory
in the user's home directory instead of being deleted. Deleted files are initially moved to theCurrentsub-directory of the.Trashdirectory,
and their original path is preserved. If trash checkpointing is enabled, theCurrentdirectory is periodically renamed using a timestamp. Files in.Trashare
permanently removed after a user-configurable time delay. Files and directories in the trash can be restored simply by moving them to a location outside the.Trashdirectory.
Trash is configured with the following properties in thecore-site.xmlfile:
|
CDH Parameter
|
Value
|
Description
|
|---|
|
fs.trash.interval
|
minutesor0
|
The number of minutes after which a trash checkpoint directory is deleted. This option can be configured both on the server and the client.
- If trash is enabled on the server configuration, then the value configured on the server is used and the client configuration is ignored.
- If trash is disabled in the server configuration, then the client side configuration is checked.
- If the value of this property is zero (the default), then the trash feature is disabled.
|
|
fs.trash.checkpoint.interval
|
minutesor0
|
The number of minutes between trash checkpoints. Every time the checkpointer runs on the NameNode, it creates a new checkpoint of the "Current" directory and removes checkpoints older thanfs.trash.intervalminutes.
This value should be smaller than or equal tofs.trash.interval. This option is configured on the server. If configured to zero (the default), then the value is set to the value
offs.trash.interval.
|
For example, to enable trash so that files deleted using the Hadoop shell are not deleted for 24 hours, set the value of the
fs.trash.intervalproperty
in the server's
core-site.xmlfile to a value of
1440.
Note:
The period during which a file remains in the trash starts when the file is moved to the trash, not when the file is last modified.
http://www.cloudera.com/content/cloudera/en/documentation/core/latest/topics/cdh_ig_hdfs_cluster_deploy.html#topic_11_2_8_unique_1
这个命令看起来是清空回收站，但实际并没有清空，只是做了一次trash checkpoint？这里我不太确定
expunge
Usage:hadoop fs -expunge
Empty the Trash. Refer to theHDFS Architecture Guidefor more information on the Trash feature.
[root@gc2 hadoop]# hadoop fs -ls /user/root/.Trash/Current/user/root
Found 2 items
-rw-r--r-- 1 root supergroup 10 2015-07-24 10:39 /user/root/.Trash/Current/user/root/slaves
-rw-r--r-- 1 root supergroup 72 2015-07-24 10:40 /user/root/.Trash/Current/user/root/sum.sh
[root@gc2 hadoop]# hadoop fs -expunge
15/07/28 00:07:11 INFO fs.TrashPolicyDefault: Namenode trash configuration: Deletion interval = 1440 minutes, Emptier interval = 0 minutes.
15/07/28 00:07:11 INFO fs.TrashPolicyDefault: Created trash checkpoint: /user/root/.Trash/150728000711
[root@gc2 hadoop]# hadoop fs -ls -R /user/root/.Trash/Current
ls: `/user/root/.Trash/Current': No such file or directory
[root@gc2 hadoop]# hadoop fs -ls -R /user/root/.Trash
drwx------ - root supergroup 0 2015-07-26 12:16 /user/root/.Trash/150728000711
drwx------ - root supergroup 0 2015-07-26 13:43 /user/root/.Trash/150728000711/snap
-rw-r--r-- 1 root supergroup 72 2015-07-26 11:55 /user/root/.Trash/150728000711/snap/sum.sh
drwx------ - root supergroup 0 2015-07-24 10:41 /user/root/.Trash/150728000711/user
drwx------ - root supergroup 0 2015-07-28 00:05 /user/root/.Trash/150728000711/user/root
-rw-r--r-- 1 root supergroup 10 2015-07-24 10:39 /user/root/.Trash/150728000711/user/root/slaves
-rw-r--r-- 1 root supergroup 72 2015-07-24 10:40 /user/root/.Trash/150728000711/user/root/sum.sh