[HDFS-3325] When configuring "dfs.namenode.safemode.threshold-pct" to a value greater or equal to 1 there is mismatch in the UI report

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: J.Andreina
• Reporter: J.Andreina
• Created: 26/Apr/12 04:07
• Updated: 21/Dec/18 02:53
• Resolved: 24/Mar/15 06:44

Description

When dfs.namenode.safemode.threshold-pct is configured to n
Namenode will be in safemode until n percentage of blocks that should satisfy
the minimal replication requirement defined by dfs.namenode.replication.min is reported to namenode

But in UI it displays that n percentage of total blocks + 1 blocks are additionally needed
to come out of the safemode

Scenario 1:
============
Configurations:
dfs.namenode.safemode.threshold-pct = 2
dfs.replication = 2
dfs.namenode.replication.min =2
Step 1: Start NN,DN1,DN2
Step 2: Write a file "a.txt" which has got 167 blocks
step 3: Stop NN,DN1,DN2
Step 4: start NN
In UI report the Number of blocks needed to come out of safemode and number of blocks actually present is different.

Cluster Summary
Security is OFF 
Safe mode is ON. The reported blocks 0 needs additional 335 blocks to reach the threshold 2.0000 of total blocks 167. Safe mode will be turned off automatically.
2 files and directories, 167 blocks = 169 total.
Heap Memory used 57.05 MB is 2% of Commited Heap Memory 2 GB. Max Heap Memory is 2 GB. 
Non Heap Memory used 23.37 MB is 17% of Commited Non Heap Memory 130.44 MB. Max Non Heap Memory is 176 MB.

Scenario 2:
===========
Configurations:
dfs.namenode.safemode.threshold-pct = 1
dfs.replication = 2
dfs.namenode.replication.min =2
Step 1: Start NN,DN1,DN2
Step 2: Write a file "a.txt" which has got 167 blocks
step 3: Stop NN,DN1,DN2
Step 4: start NN
In UI report the Number of blocks needed to come out of safemode and number of blocks actually present is different

Cluster Summary
Security is OFF 
Safe mode is ON. The reported blocks 0 needs additional 168 blocks to reach the threshold 1.0000 of total blocks 167. Safe mode will be turned off automatically.
2 files and directories, 167 blocks = 169 total.
Heap Memory used 56.2 MB is 2% of Commited Heap Memory 2 GB. Max Heap Memory is 2 GB. 
Non Heap Memory used 23.37 MB is 17% of Commited Non Heap Memory 130.44 MB. Max Non Heap Memory is 176 MB.

Issue Links

• is related to: HDFS-14164 Namenode should not be started if safemode threshold is out of boundary