[CASSANDRA-16460] Document the side-effect of Zero Copy Streaming when in a multiple data directories setup

• Type: Task
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-rc1, 4.0
• Component/s: Documentation/Website
• Change Category: Operability
• Complexity: Low Hanging Fruit
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/425f750a6ffcc65340b62692548e38855d76040f

Test and Documentation Plan

manual: build doc and inspect

• Assignee: Yifan Cai
• Reporter: Yifan Cai

Authors

Yifan Cai

Reviewers

Brandon Williams

• Created: 18/Feb/21 21:41
• Updated: 16/Mar/22 15:29
• Resolved: 26/Feb/21 17:45

Description

During the compaction test task (CASSANDRA-16345), we discovered that when zero copy streaming (ZCS) is enabled, it can lead to the streamed files contain tokens that exceed the disk boundaries (only when using multiple data directories) on the target host. Since ZCS streams the entire SSTable as is. 
We should add a proper note to the https://cassandra.apache.org/doc/latest/new/streaming.html#zero-copy-streaming section to inform people when using the feature. 

Issue Links

• is related to: CASSANDRA-16345 Test SSTables are in the correct location after range movement with 1/5/20 data directories