Can I set more than one dfs.name.dir?

["arale.jianglei@gmail.com" <ar...@gmail.com>]

Hi all:
	I found that I can set more than one dfs.name.dir in hadoop-site.xml
like below:
<property>
  <name>dfs.name.dir</name>
  <value>/opt/hadoop/dfs/name1</value>
  <value>/opt/..../name2</value>
  <description>Determines where on the local filesystem the NDFS name
node
     should store the name table.</description>
</property>

Does this mean I have a backup of my namenode info? Or this is for some
other special reasons?

Best Regards,

Jianglei
2006-11-24

RE: Can I set more than one dfs.name.dir?

[Dhruba Borthakur <dh...@yahoo-inc.com>]

Your reasoning is absolutely correct. The Namenode writes its metadata to
all these directories. This setting automatically replicates the Namenode
metadata to multiple locations.

Thanks,
dhruba 

-----Original Message-----
From: arale.jianglei@gmail.com [mailto:arale.jianglei@gmail.com] 
Sent: Friday, November 24, 2006 5:58 AM
To: hadoop-dev@lucene.apache.org
Subject: Can I set more than one dfs.name.dir?

Hi all:
	I found that I can set more than one dfs.name.dir in hadoop-site.xml
like below:
<property>
  <name>dfs.name.dir</name>
  <value>/opt/hadoop/dfs/name1</value>
  <value>/opt/..../name2</value>
  <description>Determines where on the local filesystem the NDFS name
node
     should store the name table.</description>
</property>

Does this mean I have a backup of my namenode info? Or this is for some
other special reasons?

Best Regards,

Jianglei
2006-11-24