[HDFS-8821] Explain message "Operation category X is not supported in state standby"

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Hadoop Flags: Reviewed
• Assignee: Gautam Gopalakrishnan
• Reporter: Gautam Gopalakrishnan
• Created: 25/Jul/15 07:05
• Updated: 30/Aug/16 01:30
• Resolved: 31/Jul/15 03:30

Description

There is one message specifically that causes many users to question the health of their HDFS cluster, namely "Operation category READ/WRITE is not supported in state standby".

HDFS-3447 is an attempt to lower the logging severity for StandbyException related messages but it is not resolved yet. So this jira is an attempt to explain this particular message so it appears less scary.

The text is question 3.17 in the Hadoop Wiki FAQ
ref: https://wiki.apache.org/hadoop/FAQ#What_does_the_message_.22Operation_category_READ.2FWRITE_is_not_supported_in_state_standby.22_mean.3F