[HBASE-3785] book.xml - moving WAL into architecture section, plus adding more description on what it does

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.92.0
• Hadoop Flags: Reviewed
• Assignee: Doug Meil
• Reporter: Doug Meil
• Created: 14/Apr/11 21:16
• Updated: 20/Nov/15 12:41
• Resolved: 14/Apr/11 23:06

Description

Moved the WAL into Architecture (instead of being a separate chapter)
Added a paragraph on what it does (e.g., each RS gets own WAL) plus a link to the HLog javadoc, instead of just having "see wikipedia" for what a WAL is.