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From Stas Oskin <stas.os...@gmail.com>
Subject Re: Secondary NameNodes or NFS exports?
Date Tue, 27 Oct 2009 15:51:46 GMT
Hi.

You mean, you couldn't recover the NameNode from checkpoints because of
timestamps?

Regards.

On Tue, Oct 27, 2009 at 4:49 PM, Jason Venner <jason.hadoop@gmail.com>wrote:

> We have been having some trouble with the secondary on a cluster that has
> one edit log partition on an nfs server, with the namenode rejecting the
> merged images due to timestamp missmatches.
>
>
> On Mon, Oct 26, 2009 at 10:14 AM, Stas Oskin <stas.oskin@gmail.com> wrote:
>
> > Hi.
> >
> > Thanks for the advice, it seems that the initial approach of having
> single
> > SecNameNode writing to exports is the way to go.
> >
> > By the way, I asked this already, but wanted to clarify:
> >
> > * It's possible to set how often SecNameNode checkpoints the data (what
> is
> > the setting by the way)?
> >
> > * It's possible to let NameNode write to exports as well together with
> > local
> > disk, which ensures the latest possible meta-data in case of disk crash
> > (compared to pereodic check-pointing), but it's going to slow down the
> > operations due to network read/writes.
> >
> > Thanks again.
> >
> > On Thu, Oct 22, 2009 at 10:03 PM, Patrick Angeles
> > <patrickangeles@gmail.com>wrote:
> >
> > > From what I understand, it's rather tricky to set up multiple secondary
> > > namenodes. In either case, running multiple 2ndary NNs doesn't get you
> > > much.
> > > See this thread:
> > > http://www.mail-archive.com/core-user@hadoop.apache.org/msg06280.html
> > >
> > > On Wed, Oct 21, 2009 at 10:44 AM, Stas Oskin <stas.oskin@gmail.com>
> > wrote:
> > >
> > > > To clarify, it's either let single SecNameNode to write to multiple
> NFS
> > > > exports, or actually have multiple SecNameNodes.
> > > >
> > > > Thanks again.
> > > >
> > > > On Wed, Oct 21, 2009 at 4:43 PM, Stas Oskin <stas.oskin@gmail.com>
> > > wrote:
> > > >
> > > > > Hi.
> > > > >
> > > > > I'm want to keep a checkpoint data on several separate machines for
> > > > backup,
> > > > > and deliberating between exporting these machines disks via NFS,
or
> > > > actually
> > > > > running Secondary Name Nodes there.
> > > > >
> > > > > Can anyone advice what would be better in my case?
> > > > >
> > > > > Regards.
> > > > >
> > > >
> > >
> >
>
>
>
> --
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