Or both the options are used together. NFS + SNN ?
On Wed, Apr 3, 2013 at 8:10 PM, Rahul Bhattacharjee rahul.rec@gmail.com
wrote:
Hi all,
I was reading about Hadoop and got to know that there are two ways to
protect against the name node failures.
1) To write to a nfs mount along
Hi Rahul,
The SNN does not act as a backup / standby NameNode in the event of failure.
The sole purpose of the Secondary NameNode (or as it’s otherwise / more
correctly known as the Checkpoint Node) is to perform checkpointing of the
current state of HDFS:
The SNN retrieves the
Hello Rahul,
It's always better to have both 1 and 2 together. One common
misconception is that SNN is a backup of the NN, which is wrong. SNN is a
helper node to the NN. In case of any failure SNN is not gonna take up the
NN spot.
Yes, we can't guarantee that the SNN fsimage replica will
@Vijay : We seem to be in 100% sync though :)
Warm Regards,
Tariq
https://mtariq.jux.com/
cloudfront.blogspot.com
On Wed, Apr 3, 2013 at 8:27 PM, Mohammad Tariq donta...@gmail.com wrote:
Hello Rahul,
It's always better to have both 1 and 2 together. One common
misconception is that
Thanks to all of you for precise and complete responses.
S
o in case of failure we have to bring another backup system up with the
fsimage and edit logs from the NFS filer.
SNN stays as is for the new NN.
Thanks,
Rahul
On Wed, Apr 3, 2013 at 8:38 PM, Azuryy Yu azury...@gmail.com wrote:
for
There is a 3rd, most excellent way: Use HDFS's own HA, see
http://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/HDFSHighAvailabilityWithQJM.html
:)
On Wed, Apr 3, 2013 at 8:10 PM, Rahul Bhattacharjee
rahul.rec@gmail.com wrote:
Hi all,
I was reading about Hadoop and got to
If you are not in position to go for HA just keep your checkpoint period
shorter to have recent data recoverable from SNN.
and you always have a option
hadoop namenode -recover
try this on testing cluster and get versed to it.
and take backup of image at some solid state storage.
∞
Shashwat
Thats also doable , reducing the checkpoint period would also have have
some amount of edit log loss and how short should be the checkpoint
interval has to be evaluated.I think the good way to go , in case HA is not
doable is SNN and secondary storage NFS.
Thanks,
Rahul
On Thu, Apr 4, 2013 at
