Remove one directory from multiple dfs.data.dir, how?

[elton sky]

I have a HDFS with 10 nodes. Each nodes have 4 disks attached, so I assign 4
directories for hdfs in configuration:

<property>
<name>dfs.data.dir</name>
<value>/data1/hdfs-data,/data2/hdfs-data,/data3/hdfs-data,/data4/hdfs-data</value>
</property>


Now I want to remove 1 disk from each node, say /data4/hdfs-data. What I
should do to keep data integrity?

-Elton