Thank you for the responses. I understand what safe mode means. I guess the following is the definition of the safe mode in hdfs.
1. does not accept changes to name space (read-only), and 2. does not replicate or delete blocks. However, I don't understand what would possibly go wrong if modifications to name space (rather than block replication/deletion) would be allowed in safe mode. For example, "rename file/directory", "mkdir" and etc, these seems okay to be executed in safe mode. Am I missing something here?? Can you give me some example that will show what could go wrong if modifications to name space are made in safe mode? Sangmin On Thu, Sep 25, 2008 at 8:25 PM, Lohit <[EMAIL PROTECTED]> wrote: > To be precise, when u start your namenode it would construct it's > namespace. As datanodes startup and send block reports the namespace gets > constructed. During this time namenode is in safemode. If your namenode is > insafe mode for long time that means some datanodes are yet to report their > state. > > Lohit > > On Sep 25, 2008, at 6:17 PM, "Edward J. Yoon" <[EMAIL PROTECTED]> > wrote: > > The name node safe mode means that the name node is not changing the > state of the > file system. Meta data is read-only, and block replication / removal > is not taking place. > > On Fri, Sep 26, 2008 at 5:46 AM, Sangmin Lee <[EMAIL PROTECTED]> > wrote: > Hi folks, > I am wondering why it is not allowed to modify namespace info in safemode. > Especially rename, mkdir, and severals seems okay to be executed in > safemode. > > I appreciate your help in advance. > > Sangmin > > > > > -- > Best regards, Edward J. Yoon > [EMAIL PROTECTED] > http://blog.udanax.org > >
