Thank you for the information.
I want to take a worse case scenario if the namenode fails. So you are
suggesting copying the dfs.name.dir directory. We can take regular backups
of this? Shouldn't HDFS be truly fault tolerant in this regard? If you
have 500 machines shouldn't it replicate the essential data in case of
failure.
The google file system maintains replicates server critical information as
well.
Let's say one did not have the dfs.name.dir backed up, what would happen?
Thanks,
Ankur
On 7/14/07, Raghu Angadi <[EMAIL PROTECTED]> wrote:
Ankur Sethi wrote:
> Then what? Can one bring up the new machine and start a namenode server
and
> have it repopulate on its own? Please explain?
If you bring up the new Namenode with same hostname and IP, then you
don't need to restart the Datanodes. If the hostname changes, then you
need to edit the configuration, distribute the configuration to other
nodes and restart the whole cluster.
Before bringing up the new Namenode, you need to copy ${dfs.name.dir}
directory from the original Namenode. By default, this is set to
${dfs.tmp.dir}/dfs/name. This directory has the filesystem image for the
cluster.
Raghu.
> Sorry if this has been asked before. I did research on the mailing list
and
> the FAQ page and the documentation before asking this.
>
> Thanks,
> Ankur
