Hi Nan,
When the Namenode will EXIT the safemode, you, you can assume that all
blocks ARE fully replicated. If the Namenode is still IN safemode that
mean that all blocks are NOT fully replicated.
JM
2013/1/29, Nan Zhu zhunans...@gmail.com:
So, we can assume that all blocks are fully
That is correct if you do not manually exit NN safemode.
Regards
Chen
On Jan 30, 2013 8:59 AM, Jean-Marc Spaggiari jean-m...@spaggiari.org
wrote:
Hi Nan,
When the Namenode will EXIT the safemode, you, you can assume that all
blocks ARE fully replicated. If the Namenode is still IN safemode
NN does recalculate new replication work to do due to unavailable
replicas (under-replication) when it starts and receives all block
reports, but executes this only after out of safemode. When in
safemode, across the HDFS services, no mutations are allowed.
On Wed, Jan 30, 2013 at 8:34 AM, Nan
Hi Harsh
I have a question. How namenode gets out of safemode in condition of data
blocks lost, only administrator? Accordin to my experiences, the NN (0.21)
stayed in safemode about several days before I manually turn safemode off.
There were 2 blocks lost.
Chen
On Wed, Jan 30, 2013 at 10:27
following are the configs it looks for . Unless Admin forces it to come out
of safenode, it respects below values
dfs.namenode.safemode.threshold-pct0.999fSpecifies the percentage of blocks
that should satisfy the minimal replication requirement defined by
dfs.namenode.replication.min. Values
Yes, if there are missing blocks (i.e. all replicas lost), and the
block availability threshold is set to its default of 0.999f (99.9%
availability required), then NN will not come out of safemode
automatically. You can control this behavior by configuring
dfs.namenode.safemode.threshold.
On Wed,
I think Chen is asking replication lost,
so, according to Harsh's reply, in safe mode, NN will know all blocks which has
less replications than 3(by default setup) but no less than 1, and after
getting out from safe mode, it will instruct the real replicating works? Hope I
understand it
Well, the documentation is more explicite.
Specifies the percentage of blocks that should satisfy the minimal
replication requirement defined by* dfs.namenode.replication.min*.
Which happens to be 1 by default but doesn't need to stay that way.
Regards
Bertrand
On Wed, Jan 30, 2013 at 5:45
Hi, all
I'm wondering if HDFS is stopped, and some of the machines of the cluster are
moved, some of the block replication are definitely lost for moving machines
when I restart the system, will the namenode recalculate the data distribution?
Best,
--
Nan Zhu
School of Computer Science,
Hi Nan
Namenode will stay in safemode before all blocks are replicated. During
this time, the jobtracker can not see any tasktrackers. (MRv1).
Chen
On Tue, Jan 29, 2013 at 9:04 PM, Nan Zhu zhunans...@gmail.com wrote:
Hi, all
I'm wondering if HDFS is stopped, and some of the machines of the
So, we can assume that all blocks are fully replicated at the start point of
HDFS?
Best,
--
Nan Zhu
School of Computer Science,
McGill University
On Tuesday, 29 January, 2013 at 10:50 PM, Chen He wrote:
Hi Nan
Namenode will stay in safemode before all blocks are replicated. During
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