Hi Koji, This was on CHD3U1. For the record I had the dfs.name.dir.restore which Harsh mentioned enabled as well.
Jorn -----Oorspronkelijk bericht----- Van: Koji Noguchi [mailto:knogu...@yahoo-inc.com] Verzonden: woensdag 7 december 2011 17:59 Aan: common-user@hadoop.apache.org Onderwerp: Re: HDFS Backup nodes Hi Jorn, Which hadoop version were you using when you hit that issue? Koji On 12/7/11 5:25 AM, "Jorn Argelo - Ephorus" <jorn.arg...@ephorus.com> wrote: > Just to add to that note - we've ran into an issue where the NFS share > was out of sync (the namenode storage failed even though the NFS share > was working), but the other local metadata was fine. At the restart of > the namenode it picked the NFS share's fsimage even if it was out of > sync. This had the effect that loads of blocks were marked as invalid > and deleted by the datanodes, and the namenode never came out of safe > mode because it was missing blocks. The Hadoop documentation says it > always picks the most recent version of the fsimage but in my case this > doesn't seem to have happened. Maybe a bug? With that said I've been > having issues with NFS before (the NFS namenode storage always failed > every hour even if the cluster was idle). > > Now since this was just test data it wasn't all that important ... but > if that would happen with your production cluster you got yourself a > problem. I've moved away from NFS and I'm using DRBD instead. Not having > any problems anymore whatsoever. > > YMMV. > > Jorn > > -----Oorspronkelijk bericht----- > Van: Joey Echeverria [mailto:j...@cloudera.com] > Verzonden: woensdag 7 december 2011 12:08 > Aan: common-user@hadoop.apache.org > Onderwerp: Re: HDFS Backup nodes > > You should also configure the Namenode to use an NFS mount for one of > it's storage directories. That will give the most up-to-date back of > the metadata in case of total node failure. > > -Joey > > On Wed, Dec 7, 2011 at 3:17 AM, praveenesh kumar <praveen...@gmail.com> > wrote: >> This means still we are relying on Secondary NameNode idealogy for >> Namenode's backup. >> Can OS-mirroring of Namenode is a good alternative keep it alive all > the >> time ? >> >> Thanks, >> Praveenesh >> >> On Wed, Dec 7, 2011 at 1:35 PM, Uma Maheswara Rao G > <mahesw...@huawei.com>wrote: >> >>> AFAIK backup node introduced in 0.21 version onwards. >>> ________________________________________ >>> From: praveenesh kumar [praveen...@gmail.com] >>> Sent: Wednesday, December 07, 2011 12:40 PM >>> To: common-user@hadoop.apache.org >>> Subject: HDFS Backup nodes >>> >>> Does hadoop 0.20.205 supports configuring HDFS backup nodes ? >>> >>> Thanks, >>> Praveenesh >>> > >
