I see that noone has responded so this is an affirmative that data of the entire cluster is lost when the namenode data is lost.
I suppose we will have a secondary namenode as backup but we can see that Hadoop has a long way to go. Wow, looks like the guys at google have put it a lot of hardwork. Ankur -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ankur Sethi Sent: Saturday, July 14, 2007 6:51 PM To: [email protected] Subject: Re: New user question In case the namenode data is lost the data of the entire cluster is lost? On 7/14/07, Raghu Angadi <[EMAIL PROTECTED]> wrote: > > > You can specify multiple directories for Namenode data, in which case > the image is written to all the directories. You can also an NFS mount, > raid or similar approach. > > Raghu. > > Ankur Sethi wrote: > > 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 >
