[HDFS-8157] Writes to RAM DISK reserve locked memory for block files

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Component/s: datanode
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Release Note: This change requires setting the dfs.datanode.max.locked.memory configuration key to use the HDFS Lazy Persist feature. Its value limits the combined off-heap memory for blocks in RAM via caching and lazy persist writes.
• Assignee: Arpit Agarwal
• Reporter: Arpit Agarwal
• Created: 16/Apr/15 03:07
• Updated: 30/Aug/16 01:36
• Resolved: 16/May/15 16:20

Description

Per discussion on HDFS-6919, the first step is that writes to RAM disk will reserve locked memory via the FsDatasetCache.

Issue Links

• is required by: HDFS-8192 Eviction should key off used locked memory instead of ram disk free space
• requires: HDFS-8152 Refactoring of lazy persist storage cases