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Re: backup node question
I am confused. Hadoopv2 has NN SNN DN JN(journal node), so whats
Standby Namenode?

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On Apr 7, 2013 9:03 PM, "Harsh J" <[EMAIL PROTECTED]> wrote:

> BackupNameNode is not present in the maintenance 1.x releases, it is a
> feature added to a higher version; you can try it out in 2.x today if
> you wish to.
>
> On Sun, Apr 7, 2013 at 3:12 PM, Azuryy Yu <[EMAIL PROTECTED]> wrote:
> > Hi Harsh,
> > Do you mean BackupNameNode is Secondary NameNode in Hadoop1.x?
> >
> >
> > On Sun, Apr 7, 2013 at 4:05 PM, Harsh J <[EMAIL PROTECTED]> wrote:
> >>
> >> Yes, it need not keep an edits (transactions) stream locally cause
> >> those are passed synchronously to the BackupNameNode, which persists
> >> it on its behalf.
> >>
> >> On Sun, Apr 7, 2013 at 1:21 PM, Lin Ma <[EMAIL PROTECTED]> wrote:
> >> > Thanks Harsh,
> >> >
> >> > For your comments, "What it means is that the NameNode need not store
> >> > anything locally", you mean Primary Name Node do not need to store
> >> > checkpoint/journal locally, and only need to keep memory image
> >> > up-to-date
> >> > for edits?
> >> >
> >> > regards,
> >> > Lin
> >> >
> >> >
> >> > On Sun, Apr 7, 2013 at 3:31 PM, Harsh J <[EMAIL PROTECTED]> wrote:
> >> >>
> >> >> Hi Lin,
> >> >>
> >> >> My reply inline.
> >> >>
> >> >> On Sun, Apr 7, 2013 at 12:36 PM, Lin Ma <[EMAIL PROTECTED]> wrote:
> >> >> > Hi guys,
> >> >> >
> >> >> > I am reading from this paper to learn about backup nodes
> >> >> > (http://www.storageconference.org/2010/Papers/MSST/Shvachko.pdf),
> >> >> >
> >> >> > It is mentioned, "It contains all file system metadata information
> >> >> > except
> >> >> > for block locations. It can perform all operations of the regular
> >> >> > NameNode
> >> >> > that do not involve modification of the namespace or knowledge of
> >> >> > block
> >> >> > locations. ", what kinds of operations do not need knowledge of
> block
> >> >> > locations?
> >> >>
> >> >> Operations that do not involve data reads or writes would not require
> >> >> knowledge of block locations. Applying also the restriction of no
> >> >> namespace mutation, an example would be listing directories and
> >> >> looking up file information via FileStatus objects (perhaps the only
> >> >> examples - its like a safemode but no reads either).
> >> >>
> >> >> > It is also mentioned, "Use of a BackupNode provides the option of
> >> >> > running
> >> >> > the NameNode without persistent storage, delegating responsibility
> >> >> > for
> >> >> > the
> >> >> > namespace state persisting to the BackupNode.", what means "running
> >> >> > the
> >> >> > NameNode without persistent storage" and "delegating responsibility
> >> >> > for
> >> >> > the
> >> >> > namespace state persisting"?
> >> >>
> >> >> What it means is that the NameNode need not store anything locally,
> >> >> but can rely on the edits being stored at the BackupNameNode which
> >> >> would continuously be receiving it. When restarted, it can grab a
> >> >> current checkpoint from the BNN and boot up anywhere, since there's
> no
> >> >> local storage requirement.
> >> >>
> >> >> --
> >> >> Harsh J
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Harsh J
> >
> >
>
>
>
> --
> Harsh J
>