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From Ravi Prakash <ravihad...@gmail.com>
Subject Re: HDFS Issues.
Date Wed, 12 Oct 2016 18:38:11 GMT
There are a few conditions for the Namenode to come out of safemode.
# Number of datanodes,
# Number of blocks that have been reported.

How many blocks have the datanodes reported?

On Tue, Oct 4, 2016 at 1:22 PM, Steve Brenneis <swb102856@gmail.com> wrote:

> I have an HDFS cluster of three nodes. They are all running on Amazon EC2
> instances. I am using HDFS for an HBase backing store. Periodically, I will
> start the cluster and the name node stays in safe mode because it says the
> number of live datanodes has dropped to 0.
>
> The number of live datanodes 2 has reached the minimum number 0. Safe mode will be turned
off automatically once the thresholds have been reached.
>
> The datanode logs appear to be normal, with no errors indicated. The
> dfsadmin report says the datanodes are both normal and that the name node
> is in contact with them.
>
> Safe mode is ON
> Configured Capacity: 16637566976 (15.49 GB)
> Present Capacity: 7941234688 (7.40 GB)
> DFS Remaining: 7940620288 (7.40 GB)
> DFS Used: 614400 (600 KB)
> DFS Used%: 0.01%
> Under replicated blocks: 0
> Blocks with corrupt replicas: 0
> Missing blocks: 0
> Missing blocks (with replication factor 1): 0
>
> -------------------------------------------------
> Live datanodes (2):
>
> Name: 172.31.52.176:50010 (dev2)
> Hostname: dev2
> Decommission Status : Normal
> Configured Capacity: 8318783488 (7.75 GB)
> DFS Used: 307200 (300 KB)
> Non DFS Used: 3257020416 (3.03 GB)
> DFS Remaining: 5061455872 (4.71 GB)
> DFS Used%: 0.00%
> DFS Remaining%: 60.84%
> Configured Cache Capacity: 0 (0 B)
> Cache Used: 0 (0 B)
> Cache Remaining: 0 (0 B)
> Cache Used%: 100.00%
> Cache Remaining%: 0.00%
> Xceivers: 1
> Last contact: Tue Oct 04 15:47:00 EDT 2016
>
>
> Name: 172.31.63.188:50010 (dev1)
> Hostname: dev1
> Decommission Status : Normal
> Configured Capacity: 8318783488 (7.75 GB)
> DFS Used: 307200 (300 KB)
> Non DFS Used: 5439311872 (5.07 GB)
> DFS Remaining: 2879164416 (2.68 GB)
> DFS Used%: 0.00%
> DFS Remaining%: 34.61%
> Configured Cache Capacity: 0 (0 B)
> Cache Used: 0 (0 B)
> Cache Remaining: 0 (0 B)
> Cache Used%: 100.00%
> Cache Remaining%: 0.00%
> Xceivers: 1
> Last contact: Tue Oct 04 15:47:00 EDT 2016
>
> If I force the name node out of safe mode, the fsck commmand says that the
> file system is corrupt. When this happens, the only thing I've been able to
> do to get it back is to format the HDFS file system. I have not changed the
> configuration of the cluster. This just randomly seems to occur. The system
> is in development, but this will be unacceptable in production.
> I’m using version 2.7.3. Thank you in advance for any help.
>
>

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