[HADOOP-8630] rename isSingleSwitch() methods in new topo base class to isFlatTopology()

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Won't Fix
• Affects Version/s: 2.0.0-alpha, 3.0.0-alpha1
• Component/s: util
• Assignee: Tsuyoshi Ozawa
• Reporter: Steve Loughran
• Created: 28/Jul/12 00:30
• Updated: 12/May/16 18:24
• Resolved: 15/Apr/13 18:43

Description

The new topology logic that is not yet turned on in HDFS uses the method isSingleSwitch() for implementations to declare whether or not they are single switch.

The use of "switch" is an implementation issue; the big VM-based patch shows that really it's about "flat" vs "hierarchical", with Hadoop assuming that subtrees in the hierarchy have better bandwidth (good) but correlated failures (bad).

Renaming the method now before it's fixed and used is time time to do it.

Issue Links

• is depended upon by: HDFS-2492 BlockManager cross-rack replication checks only work for ScriptBasedMapping