You are viewing a plain text version of this content. The canonical link for it is here.
Posted to common-user@hadoop.apache.org by Cagdas Gerede <ca...@gmail.com> on 2008/05/15 02:54:57 UTC
HDFS: Forcing Master to Leave Safemode
What is the implication of manually forcing name node to leave safemode?
What properties do HDFS lose by doing that?
One gain to that is that the file system will be available for writes
immediately.
Cagdas
--
------------
Best Regards, Cagdas Evren Gerede
Home Page: http://cagdasgerede.info
Re: HDFS: Forcing Master to Leave Safemode
Posted by Cagdas Gerede <ca...@gmail.com>.
What are the cases that a system can go into safemode?
1) When master starts.
2) ?
What are the actions that are being carried out during safemode?
1) Wait for block reports, Process block reports, Construct the blockmap in
memory.
2) ?
Cagdas
On Thu, May 15, 2008 at 4:20 AM, Ted Dunning <td...@veoh.com> wrote:
>
> That really depends on why the name node is in safemode.
>
> If the reason is system startup in which only a few datanodes have reported
> in, then the only problem is that some files may not be fully present.
>
> If the reason is some sort of system corruption, it could be a really big
> mistake to force the system out of safe mode, mostly likely because you are
> forcing the system out in order to cause more damage.
>
>
>
>
> On 5/14/08 5:54 PM, "Cagdas Gerede" <ca...@gmail.com> wrote:
>
> > What is the implication of manually forcing name node to leave safemode?
> >
> > What properties do HDFS lose by doing that?
> >
> > One gain to that is that the file system will be available for writes
> > immediately.
> >
> >
> > Cagdas
>
>
--
------------
Best Regards, Cagdas Evren Gerede
Home Page: http://cagdasgerede.info
Re: HDFS: Forcing Master to Leave Safemode
Posted by Ted Dunning <td...@veoh.com>.
That really depends on why the name node is in safemode.
If the reason is system startup in which only a few datanodes have reported
in, then the only problem is that some files may not be fully present.
If the reason is some sort of system corruption, it could be a really big
mistake to force the system out of safe mode, mostly likely because you are
forcing the system out in order to cause more damage.
On 5/14/08 5:54 PM, "Cagdas Gerede" <ca...@gmail.com> wrote:
> What is the implication of manually forcing name node to leave safemode?
>
> What properties do HDFS lose by doing that?
>
> One gain to that is that the file system will be available for writes
> immediately.
>
>
> Cagdas