The intended behavior of CombGuidGenerator is to provide a sequence of GUID values that are in ascending order. The original article regarding CombGuids is:

http://www.informit.com/articles/article.aspx?p=25862&seqNum=7

But it is not clear that the same generation algorithm that works for SQL Server works for MongoDB. For MongoDB the sort order of GUIDs might depend on:

1. Which representation is being used for GUIDs (Standard, CSharpLegacy, etc...)
2. How the server compares two BinData values

The task for this JIRA ticket is to investigate all the factors related to CombGuidGenerator and to make any changes as might be necessary (and to document the purpose and use of CombGuids).