Bug 177418

Summary: Doc: Need an explanation of logic for split-brain syndrome with RHCS4
Product: [Retired] Red Hat Cluster Suite Reporter: Paul Kennedy <pkennedy>
Component: rh-cs-enAssignee: Paul Kennedy <pkennedy>
Status: CLOSED NOTABUG QA Contact: Cluster QE <mspqa-list>
Severity: medium Docs Contact:
Priority: medium    
Version: 4CC: adstrong, cluster-maint, djuran, stakagi
Target Milestone: ---Keywords: Documentation
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-01-04 17:11:42 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 190206    

Description Paul Kennedy 2006-01-10 15:38:28 UTC 
Description of problem:
Extracted from from email to cluster-list from Shinya Takagi, 1/10/06:
Need an explanation of logic for split-brain syndrome with RHCS4

"...As all we know, RHCS4 doesn't have network tiebreaker anymore especially
4 or more nodes.
Then, how application (in this case. cman is...I guess) will detect to
be a master node and what kind of logic are following to be a master
node ? And I wonder which node will become the master node if 2 and 2
split brain syndrome was occurred in 4 node cluster system. Is that same
logic as 2-node cluster, which is basically faster node to be able to
contact to fencing device (very primitive way  :-)  ) ?

In RHEL3 CS, each node has a "map" who is a master and always being
compared.
So that if split brain was occurred, voting to other nodes and decided
which one will be fenced.
Does it RHCS3 and RHCS4 are used all same logic for fencing ?..."


Version-Release number of selected component (if applicable):
rh-cs(EN)-4-HTML-RHI (2005-11-30T16:52) and
rh-cs(EN)-4-Print-RHI (2005-11-30T16:52)

How reproducible:
N/A

Steps to Reproduce: N/A
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Actual results:
N/A

Expected results:
N/A

Additional info: none
Comment 1 David Lawrence 2006-04-18 20:32:49 UTC 
NEEDINFO_ENG has been deprecated in favor of NEEDINFO or ASSIGNED. Changing
status to ASSIGNED for ENG review.
Comment 4 Paul Kennedy 2007-01-04 17:11:42 UTC 
Unless there is a defect in the cluster software, there is no possiblity of a
split-brain cluster. However, the concept of split-brain is covered in RHCS4
overview doc.