Question on Quorum

Hi Experts,
Couple of questions on Windows Clusters. I am not a cluster expert and look for some help to understand the concepts
1. In Win 2003 cluster, we have quorum disk and "Disk only quorum model". IF this quorum model is used, and if quorum disk is down, then cluster is down. So, my question is what quorum disk contain? All I know is, it contains cluster
related information. But what kind of info is stored in quorum disk which is so critical.
2. Secondly, from Win 2008 and above cluster, we have new quorum models(i.e node majority, node + disk witness ...), in these new quorum models, do we still have quorum disk? And where does cluster information is stored? I came to know that cluster information
is stored or replicated to all nodes and each node has its own copy. I wanted to know is this true or not. pl correct me if am wrong. If this information is correct, how does the cluster info replication happens? Can anybody explain in simple terms?
Any links/msdn blogs or resources would be a great help for reference.
Thanks in advance.

Hi Samantha v,
For 2003 cluster before giving an explanation of what a cluster quorum is, it is important to understand the background to Windows Clustering Technologies.
Starting with Microsoft® Windows NT® 4.0 Enterprise Edition, Microsoft introduced the idea of a cluster, which is simply a group of servers that are presented as one virtual
server. For example, you can configure two servers, server A and server B, in a cluster, and present them to the outside world as server C (a virtual server). If, for example, server A dies, server B is used to ensure that the virtual server (server C) and
the services it offered, are still available to clients, thereby providing transparent access to the user. You can refer the following related KB for more detail information:
Background (Server Clusters: Quorum Options - Windows Server 2003)
http://technet.microsoft.com/en-us/library/cc780689(v=ws.10).aspx
Quorum Drive Configuration Information
http://support.microsoft.com/kb/280345
Frequently Asked Questions (Server Clusters: Quorum Options - Windows Server 2003)
http://technet.microsoft.com/en-us/library/cc737067(v=ws.10).aspx
For 2008 or later cluster you can refer the following article:
New Cluster Quorum Models in Windows 2008
http://blogs.msdn.com/b/saponsqlserver/archive/2010/06/30/new-cluster-quorum-models-in-windows-2008.aspx
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Similar Messages

Question on Quorum : Windows Server 2012 R2 + SQL 2014 AlwaysOn AG

OS on all nodes : Windows Server 2012 R2
SQL on all nodes : SQL Server 2014 CU2
2 cluster nodes in primary data center and AlwaysOn AG doing Sync Transfer between these nodes with auto failover.
2 cluster nodes in DR data center(Different subnet) and AlwaysON AG doing an Async Transfer between primary replica and these nodes with manual failover.
As this is a multi sub-net cluster we are giving DR nodes 0 vote. 2 nodes on primary DC has votes and a file share on the primary DC has a vote.
If the primary DC is gone,then should we re-assign node votes to the 2 nodes in DR site and again manually configure a file share witness and give it a vote?
Whats the best strategy here? Any recommendation is highly appreciated.
Thank you,

Anup,
Think if we have network issues between Primary DC and DR DC. DR node might think…Hey, I’m the only one running now. I can take all the resources. We do not want nodes in the secondary site to contribute to a decision to take the cluster offline
when there is nothing wrong with the primary site. Do you mean to say Dynamic Quorum is smart enough to handle this situation?
Is it smart enough on it's own? No. That's why someone has to determine which site they want to stay up.
If you're using dynamic quorum, a new property was introduced called "LowerQuorumPriorityNodeID" which is set at the cluster level. Give it the node of one and only one of the secondary site servers. Set a fileshare witness (if possible) as the
odd vote and make sure both sites can see it equally well. Set this property on the cluster for a node on the secondary site.
http://technet.microsoft.com/en-us/library/dn265972.aspx#BKMK_TieBreak
Assume that the fileshare goes down and you have 2 nodes at the local site and 2 nodes at the DR site. Suddenly, communicates between the two are severed. If you have dynamic quorum set and the property I mentioned above, the secondary site will shut down
and the local site will stay up as the secondary site is set for a lower precedence.
Please note, the only reason I brought this up was because you're on Windows Server 2012R2 as this is when it was first introduced.
-Sean
Sean Gallardy | Blog | Microsoft Certified Master

Design Question: Can I use Rest-CsPoolRegisterState command in order start Front End Service when Quorum is lost and less than 85% of FES are available?

Hi,
Assuming below setup for Enterprise edition Lync 2013
Single Pool Stretched architecture with 4 FES servers
Site A Data Center
Site B Data Center
FES
2
2
SQL
1 Primary
1 Mirror
Fact: In a situation when we lose network connectivity to Site A DC, and due to less than 50% FES servers, Quorum will be lost and as a result Front End Service will stop after 5 minutes.
The question is, would I be able to do a manual intervention by using this command
Reset-CsPoolRegistrarState –PoolFqdn <pool name fqdn> –ResetType QuorumLossRecovery , and start FES with just 2 FES servers in Site B DC and 1 SQL
Server?
The reason I am asking this question is because it is mentioned in one of the Lync manuals that at least 85% of the servers must be available to recover once the Quorum has lost. The same manual also mentions to use above
mentioned command in order to recover from Quorum Loss despite the fact that the lost FES servers are still not available.
Thanks in Advance

Hi,
In Lync server 2013 Stretched pools are not supported for the Front End, Edge, Mediation, and Director server roles. It need two Lync pools.
If one pool fail to connect, An administrator can declare an emergency and fail over the pool to the backup pool. That is done by using the:
Invoke-CsPoolFailover –PoolFQDN <Pool fqdn> –DisasterMode –Verbose
More details:
http://blog.avtex.com/2012/07/26/understanding-lync-2013-server-failover/
Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information
found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.
Best Regards,
Eason Huang
Eason Huang
TechNet Community Support

Question on Software Quorum

I've been reading mixed reports on the functionality of Software Quorum. Hopefully someone can help clarify this for me.
Does the Software Quorum feature in 3.2u2 only allow for non-SCSI disks to be used as quorum devices? Or does it also emulate scsi-reservations/fencing on all shared disks, whether they are quorum disks or not?
Thanks!

Did you read this blog posting. If not, it should answer your questions. If it doesn't give you all the answers, then please add a comment. The article author should then respond pretty quickly.
Regards,
Tim
---

Quorum exam question

just been doing some revision from my 70-412 exam and i have a question. four servers, 2 in main branch and 2 in remote branch are part of a cluster. you are supposed to choose two option that will result in the cluster remaining available if two node from
the same site fail. knowing that best practice is to have either disk or file share majority, but the question doesnt say anything about a third site. so am i supposed to just put node majority and no majority disk only. it feels wrong some how. I guess i
know the answer but it just sucks having to go against everything you know thats supposed to be right. cant help feeling im wrong somehow....

But how can i use node majority when i need 50% + 1 for quorum and the the question says storage is replicated btwn main branch and the remote. can i use No majority disk only and node and file share??

Quorum Server Redundancy Question

Hi All,
I'm just investigating my options for a new cluster configuration and was trying to find out about multiple quorum servers hosts. All the examples I have come across in the documentation have 1 physical host acting as a quorum server for an n+1 node cluster. I'm ssuming that there will be quorum issues in the event the physical host, hosting the quorum server, is down and the cluster nodes performed a reconfiguration/switch when the quorum server was unavailable.
Is it possible to have 2 physical hosts, with quorum servers defined on each, that can then be confidured in to the cluster. Effectivly pointing at two different quorum servers for votes?

Correct, the QS is only used if the cluster changes state, i.e. nodes leave or join. However, having more than 1 QS for a single cluster does not help. You simply lower your overall availability because there are more failure scenarios where one of these is down, leading to insufficient votes for the remaining cluster node to obtain.
Active monitoring and prompt repair of the QS (or QD) is the right approach.
Tim
---

Quorum disk question

What is the best practice for the quorum disk asignment in a dual-node cluster ?
1.Is there any benefit to have a dedicated quorum disk and if yes - what size should it be ?
2.The manual says: "Quorum devices can contain users data". Does it mean they can contain the NFS shared data in the NFS cluster? Is there a problem that the quorum device in this case will be under the volume manager (SVM or VxVM) control ?
TIA

Best practice is to use a disk that is actively used within the cluster as a quorum disk. This means that because data is frequently read from and written to the disk, any problems with the disk will be highlighted very quickly. That way a new QD can be nominated before the old disk fails and causes the entire cluster to fail if one node then goes down. (This would happen because the remaining node would not be able to gain majority).
A QD can be any shared disk with data on undere SVM or VxVM control or just on it's own.

ASM quorum disk question

Hi,
Documentation says that the QUORUM disks does not contain any user data and the QUORUM disk are added as the failure groups to the disk groups? didnt find much on google as well.
Can any one please confirm
1. are the quorum disks created to contain the VOTING or OCRs (RAC)?
2. what data does the quorum disks contain. if it is not holding any user data?
3. use of quorum disks?
Thanks,
Vishnu P

855370 wrote:
Hi,
Documentation says that the QUORUM disks does not contain any user data and the QUORUM disk are added as the failure groups to the disk groups? didnt find much on google as well.
Can any one please confirm
1. are the quorum disks created to contain the VOTING or OCRs (RAC)?
2. what data does the quorum disks contain. if it is not holding any user data?
3. use of quorum disks?
Thanks,
Vishnu P
>Hi,
Documentation says that the QUORUM disks does not contain any user data and the QUORUM disk are added as the failure groups to the disk groups? didnt find much on google as well.
Can any one please confirm
1. are the quorum disks created to contain the VOTING or OCRs (RAC)?
2. what data does the quorum disks contain. if it is not holding any user data?
3. use of quorum disks?
Thanks,
Vishnu P
Back in the 1980 Digital Equipment Corporation (DEC), first created the VAX & then created the VAX Cluster.
When you had an even number of systems, you did not want each half to think they were a valid cluster (bifurcate).
In order to avoid this problem DEC added a Quorum Disk. A valid Cluster was 50% + 1 members.
In a two node RAC, you don't want each system independently decide it was the remaining cluster member
& not share changes with the other system.

Quorum questions

Hi,
Anyone can help me on how to remove the node2 out from my quorum device, d2 ? and does it matter for the d2 to be offline? cos i have tried to add another d3 into the quorum device, and then removed d2 and and added in d2 and removed d3 again, but d2 is still offline status. i also have tried scconf -c -q globaldev=d2,reset but also no help (d2 still offline)
currently node1 is able to reboot and up and running as a cluster member, but node2 has already down (need to re-install).
node1 # scstat -q
-- Quorum Summary --
Quorum votes possible: 1
Quorum votes needed: 1
Quorum votes present: 1
-- Quorum Votes by Node --
Node Name Present Possible Status
Node votes: node1 1 1 Online
Node votes: node2 0 0 Offline
-- Quorum Votes by Device --
Device Name Present Possible Status
Device votes: /dev/did/rdsk/d2s2 0 0 Offline

Hi,
my problem is my node2 has down, and d2 is the last quorum disk, i can't simply use "scconf -r -q globaldev=d2" command, what i wan is to remove my last quorum disk out from node2 nodelist, while node1 is still controlling it, is that possible to have just 1 node with last quorum disk control ?
the status of my node2 is offline status
node1 # scstat -q
-- Quorum Summary --
Quorum votes possible: 1
Quorum votes needed: 1
Quorum votes present: 1
-- Quorum Votes by Node --
Node Name Present Possible Status
Node votes: node1 1 1 Online
Node votes: node2 0 0 Offline
-- Quorum Votes by Device --
Device Name Present Possible Status
Device votes: /dev/did/rdsk/d2s2 0 0 Offline
rdgs.

Quorum Server Question

Hi All,
If using two or more clusters, can cluster nodes be quorum servers for
for other clusters?
/Regards
Ulf

Yes, if is feasible. There have been discussions internally about the possibility of making an HA quorum server. Personally, I'm not sure of the value of doing this as you need to guard against the possibility of correlated failured that cause everything to fail in a cascading manner.
Tim
---

Questions on Db Mirroring

Hi All,
I have below questions on database mirroring.
I am using sql server 2008 sp3 Developer Edition.
I am using High Availability mode (Syncronous, witness & Automatic failover).
Here is what I observed and wanted to know reason for the below behavior.
A - Principal Server
B - Mirror Server
C - Witness Server
Scenario-1
The mirroring state is SYNCRONIZED. Meaning no more log records to be sent to Mirror db.
Now, say, Witness is down
After 3 minutes later, Principal is down.
At this point, there is only my Mirror instance is running with role as Mirror.
My question here is, how can I make this Mirror as Principal.
Since my Principal and Witness is down, I cannot run below command
use master
go
ALTER DATABASE <database_name> SET PARTNER FAILOVER
go
Scenario-2
Its a continuation question on Scenario-1.
Mirroring state is SYNCRONIZED
witness is down
Principal is down
only mirror is up and running but couldnt come online.
I tried starting Witness , hoping that , mirror and witness are now connected and can form Quorum and make Mirror as Principal, but that didn't happen.
I checked below command
select name,state_Desc from sys.databases
and I can see it is in recovering state and couldn't come online.
I Even tried below so that startup is initiated and recovery can run on that database.
use <dbname>
go
IT throws me an error saying, quorum cannot be forum. Error is
Database %.*ls is enabled for Database Mirroring, but the database lacks quorum: the database cannot be opened. Check the partner and witness connections if configured.
Question here is, even after starting my witness server , why it couldnt form a Quorum and why didnt Mirror wasnt able to become new Principal.
From the Database monitor tool, it is very evident that, Mirror and Witness are connected but only Pricipal is disconnected as it is down.
Eventually, when I started the Principal server (i.e A), it became as Principal and Mirror was Mirror (there's no change in role)
One more thing, I want to mention here is, I am not using FQDN's. Does it make any difference. I have installed 3 sql instances on my Desktop and worked on it.
Again, I have tested by bring the Principal down and it automatically failover to the Mirror server (i.e. B).
Principal --> TCP://TESTING-PC:5022
Mirror --> TCP://TESTING-PC:5023
Witness --> TCP://TESTING-PC:5024
Appreciate if someone can provide comments/suggestions on Scenario-1 and Scenario-2.
Thank you in advance.

Hello,
Seems you did not reffered to document i provided in question you asked about mirroring.Anyways I will try to answer your scenario
1.>>The mirroring state is SYNCRONIZED. Meaning no more log records to be sent to Mirror db.
Wrong assumption it means your mirroring is working fine and Principal is sending log records to mirror and mirror is trying to make changes and commit it.Its not like, no log records would be sent.
If Witness is down no effect on mirroring now if principal is also down your mirroring is gone and since Mirror database cannot for Quorum with witness no failover will happen and you need to manually break mirroring and bring Mirror DB online.
2.In second scenario you need first break the mirroring and then recovery on mirror database.Even if you start witness i Doubt it will form quorum
--run this on mirror database
use master
go
alter database db_name set partner off
go
restore database db_name with recovery
Please read below article for understandin how Quorum works
http://msdn.microsoft.com/en-us/library/ms189902.aspx
Please mark this reply as the answer or vote as helpful, as appropriate, to make it useful for other readers

Cluster Quorum Disk failing inside Guest cluster VMs in Hyper-V Cluster using Virtual Disk Sharing Windows Server 2012 R2

Hi, I'm having a problem in a VM Guest cluster using Windows Server 2012 R2 and virtual disk sharing enabled.
It's a SQL 2012 cluster, which has around 10 vhdx disks shared this way. all the VHDX files are inside LUNs on a SAN. These LUNs are presented to all clustered members of the Windows Server 2012 R2 Hyper-V cluster, via Cluster Shared Volumes.
Yesterday happened a very strange problem, both the Quorum Disk and the DTC disks got the information completetly erased. The vhdx disks themselves where there, but the info inside was gone.
The SQL admin had to recreated both disks, but now we don't know if this issue was related to the virtualization platform or another event inside the cluster itself.
Right now I'm seen this errors on one of the VM Guest:
Log Name: System
Source: Microsoft-Windows-FailoverClustering
Date: 3/4/2014 11:54:55 AM
Event ID: 1069
Task Category: Resource Control Manager
Level: Error
Keywords:
User: SYSTEM
Computer: ServerDB02.domain.com
Description:
Cluster resource 'Quorum-HDD' of type 'Physical Disk' in clustered role 'Cluster Group' failed.
Based on the failure policies for the resource and role, the cluster service may try to bring the resource online on this node or move the group to another node of the cluster and then restart it. Check the resource and group state using Failover Cluster
Manager or the Get-ClusterResource Windows PowerShell cmdlet.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-FailoverClustering" Guid="{BAF908EA-3421-4CA9-9B84-6689B8C6F85F}" />
<EventID>1069</EventID>
<Version>1</Version>
<Level>2</Level>
<Task>3</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000000</Keywords>
<TimeCreated SystemTime="2014-03-04T17:54:55.498842300Z" />
<EventRecordID>14140</EventRecordID>
<Correlation />
<Execution ProcessID="1684" ThreadID="2180" />
<Channel>System</Channel>
<Computer>ServerDB02.domain.com</Computer>
<Security UserID="S-1-5-18" />
</System>
<EventData>
<Data Name="ResourceName">Quorum-HDD</Data>
<Data Name="ResourceGroup">Cluster Group</Data>
<Data Name="ResTypeDll">Physical Disk</Data>
</EventData>
</Event>
Log Name: System
Source: Microsoft-Windows-FailoverClustering
Date: 3/4/2014 11:54:55 AM
Event ID: 1558
Task Category: Quorum Manager
Level: Warning
Keywords:
User: SYSTEM
Computer: ServerDB02.domain.com
Description:
The cluster service detected a problem with the witness resource. The witness resource will be failed over to another node within the cluster in an attempt to reestablish access to cluster configuration data.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-FailoverClustering" Guid="{BAF908EA-3421-4CA9-9B84-6689B8C6F85F}" />
<EventID>1558</EventID>
<Version>0</Version>
<Level>3</Level>
<Task>42</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000000</Keywords>
<TimeCreated SystemTime="2014-03-04T17:54:55.498842300Z" />
<EventRecordID>14139</EventRecordID>
<Correlation />
<Execution ProcessID="1684" ThreadID="2180" />
<Channel>System</Channel>
<Computer>ServerDB02.domain.com</Computer>
<Security UserID="S-1-5-18" />
</System>
<EventData>
<Data Name="NodeName">ServerDB02</Data>
</EventData>
</Event>
We don't know if this can happen again, what if this happens on disk with data?! We don't know if this is related to the virtual disk sharing technology or anything related to virtualization, but I'm asking here to find out if it is a possibility.
Any ideas are appreciated.
Thanks.
Eduardo Rojas

Hi,
Please refer to the following link:
http://blogs.technet.com/b/keithmayer/archive/2013/03/21/virtual-machine-guest-clustering-with-windows-server-2012-become-a-virtualization-expert-in-20-days-part-14-of-20.aspx#.Ux172HnxtNA
Best Regards,
Vincent Wu
Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Quorum Query

Environment
2 Node RAC Cluster with each containing:
Oracle Linux 6 Update 5 (x86-64)
Oracle Grid Infrastructure 12R1 (12.1.0.2.0)
Oracle Database 12R1 (12.1.0.2.0)
I am not understanding the role of the quorum in the quorum failure group for Voting Files with Oracle ASM.
Failure Groups (FG) provide assurance that there is separation of the risk you are trying to mitigate. The separation is at the extent level with User Data. With Voting Files, the file is separated to a disk for each FG within Disk Group (DG). If Voting Files are stored on a Disk Group (DG) at normal redundancy. A minimum of two FGs are required. It is recommended that 3 FGs be used. This is so Partner Status Table (PST) can have at least one other FG where PST is maintain for comparison. This is in the event of one FG failure. Do the FGs need to be QUORUM that are storing Voting Files? What is the role of the Quorum? When is it needed?

Hi,
I'll start with what Quorum means:
A quorum is the minimum number of members (majority) of a set, necessary to prevent a failure. (IT concept)
There is many quorum such as Votedisk Quorum, OCR Quorum, Network Quorum, PST Quorum,etc
We need separate what quorum we are concerned.
The Quorum of PST is different of Quorum of Votedisk, although all thinks works toogheter.
Quorum PST:
A PST contains information about all ASM Disk in a Diskgroup - Disk Number, Disk Status, Disk Partner Number, Heartbeat info and Failgroup Info.
A Disk Group must be able to access a quorum of the Partner Status Tables (PST) to mount the diskgroup.
When diskgroup mount is requested the instance reads all disks in the disk group to find and verify all available PST. Once it verifies that there are enough PSTs for a quorum, it mounts the disk group.
There is a nice post here: ASM Support Guy: Partnership and Status Table
Quorum Votedisk:
Is a minimum number of votes to cluster be operational. There is always a votedisk quorum.
When you setup votedisk in a normal redundancy you have 3 Votedisk one in each Failgroup. To cluster be operational you need at least a quorum with 2 vote online to cluster remain online.
Quorum Failgroup (clause):
Quorum Failgroup is an option of setup of a Diskgroup.
This option must not be confused with Voting Quorum, because Voting Quorum and Failgroup Quorum are different things.
For example: In a Normal Redudancy diskgroup I can lost my Quorum Failgroup and the Cluster will remain online with 2 Regular Failgroup, so Quorum failgroup is a setup.
Oracle named as "Failgroup Quorum" a failegroup to a specific purpose that is store only Votedisk due a infrastructure deployment.
Is not mandatory use "Quorum Failgroup" in a Diskgroup that hold votedisk.
Now back to your question:
If your failure groups only have 1 ASM Disk then shouldn't the recommendation be to use High Redundancy (5 failure groups) so in the event of a ASM disk failure a quorum of PST (3 PSTs) would be possible?
About PTS Quorum: You need must be aware that if you have 5 PST you will need at least a quorum with 3 PST to mount its Diskgroup.
If you have 5 Failgroup and each Failgroup has only one ASMDISK you will have one PTS per ASMDISK that support you lost at least 2 PST to be able make a Quorum with 3 PST and keep Diskgroup Mounted or Mount it.
The bold italicized Oracle documentation above seems to say that if you allocate 3 disk devices that 2 will be used by failure groups in Normal Redundancy. Further, a quorum failure group will exist that will use all disk devices. What does this mean?
I have no idea what documentation are saying is so confuse. I'll try contact some Oracle employee to check it.
But will try clarify some things:
Suppose you setup a Diskgroup as follow:
Diskgroup DATA
Failgroup data01
* /dev/hdisk1 and /dev/hdisk2
Failgroup data02
* /dev/hdisk3 and /dev/hdisk4
Failgroup data03
* /dev/hdisk5 and /dev/hdisk6
Quorum Failgroup data_quroum
* /nfs/votedisk
When you add Votedisk on this diskgroup DATA, the CSSD will store as follow:
CSSD will pick randomly one asmdisk per Failgroup and store votedisk on it, but always will pick one ASMDISK from Quorum Failgroup (if exists).
So, after add votedisk in below diskgroup you can have:
* Failgroup data01 ( /dev/hdisk2)
* Failgroup data03 (/dev/hdisk5)
* Failgroup data_quorum (/nfs/votedisk)
To mount diskgroup DATA you need failgroup data01,data03 and data_quorum available to mount diskgroup, otherwise diskgroup does not mount.
About Documentation (https://docs.oracle.com/database/121/CWADD/votocr.htm#CWADD91889) is a bit confuse:
Normal redundancy
The redundancy level that you choose for the Oracle ASM disk group determines how Oracle ASM mirrors files in the disk group, and determines the number of disks and amount of disk space that you require. If the voting files are in a disk group, then the disk groups that contain Oracle Clusterware files (OCR and voting files) have a higher minimum number of failure groups than other disk groups because the voting files are stored in quorum failure groups.
What it saying is: In case of use Quorum Failgroup you will have a higher minimum number of failure groups than other disk groups...
But remember that qorum Failgroup is optional for those that use a single storage or odd number of storage H/W.
For Oracle Clusterware files, a normal redundancy disk group requires a minimum of three disk devices (two of the three disks are used by failure groups and all three disks are used by the quorum failure group) and provides three voting files and one OCR and mirror of the OCR. When using a normal redundancy disk group, the cluster can survive the loss of one failure group.
Trying clarify:
- Votedisk in Diskgroup with normal redundancy requires three disk devices. (In case of use Quorum Failgroup: you will have two of three disk used by Regular failgroup and one of three disk are used by Quorum Failgroup but all three disks (regular and quorum failgroup that store votedisk) count when mount that diskgroup.
- and one OCR and mirror of the OCR:
It's really confuse. Because the mirror of OCR must be placed in a different diskgroup because the OCR is stored similar to how Oracle Database files are stored. The extents are spread across all the disks in the diskgroup.
I don't know what it's talking about. If mirror of extent about diskgroup redundancy or OCR Mirror.
Per as note and above documentation says it's not possible store OCR and OCR Mirror on same diskgroup
RAC FAQ (Doc ID 220970.1)
How is the Oracle Cluster Registry (OCR) stored when I use ASM?
And (https://docs.oracle.com/database/121/CWADD/votocr.htm#CWADD90964)
* At least two OCR locations if OCR is configured on an Oracle ASM disk group. You should configure OCR in two independent disk groups. Typically this is the work area and the recovery area.
High redundancy:
For Oracle Clusterware files, a high redundancy disk group requires a minimum of five disk devices (three of the five disks are used by failure groups and all five disks are used by the quorum failure group) and provides five voting files and one OCR and two mirrors of the OCR. With high redundancy, the cluster can survive the loss of two failure groups.
Three of five disks are used ??? and Two mirror of OCR?? In a single Diskgroup?
Now things goes bad.
Far as I can test and see when use Quorum Votedisk Four (not three) of five disks are used and all five counts.

Question about cluster node NodeWeight property

Hi,
I have a three nodes (A/B/C) windows 2008 r2 sp1 cluster testCluster, and installed KB2494036 for three nodes,suppose Node A is a active node.
I configured node C's NodeWeight property to 0, and node A and node B keep default (NodeWeight=1). I also added a shared disk Q for cluster quorum.
So i want to know if node C and Node B are down , is the windows cluster testCluster down as lost of quorum or keep up?
At the first i thought testCluster should keep up , because the cluster has 2 votes (node A and quorum), node B is down, node C doesn't join voting. But after testing, testCluster was down as lost of quorum.
So anybody konw the reason,thanks.

Hello mark.gao,
Let me see if I understand correctly your steps, so I can think that if you create your cluster with three nodes at the beginning your quorum model should be "Node Majority", then you have three votes one per each node.
Then was removed the vote for Node "C" and added a disk to be witness for cluster quorum, at this point we have two out of three votes from the original configuration on "Node Majority"
Question:
At some point you changed the quorum model to be "Node and Disk Majority"???
Maybe this is the issue, you are stuck on "Node Majority" and when "B" and "C" nodes are down we have only one vote from node "A" therefore there is no quorum to keep the service online.
On 2012 we have the awesome option to configure a Dynamic Quorum:
Dynamic quorum management
In Windows Server 2012, as an advanced quorum configuration option, you can choose to enable dynamic quorum management by cluster. When this option is enabled, the cluster dynamically manages
the vote assignment to nodes, based on the state of each node. Votes are automatically removed from nodes that leave active cluster membership, and a vote is automatically assigned when a node rejoins the cluster. By default, dynamic quorum management is enabled.
Note
With dynamic quorum management, the cluster quorum majority is determined by the set of nodes that are active members of the cluster at any time. This is an important distinction from the cluster quorum in Windows Server 2008 R2, where the quorum
majority is fixed, based on the initial cluster configuration.
With dynamic quorum management, it is also possible for a cluster to run on the last surviving cluster node. By dynamically adjusting the quorum majority requirement, the cluster can sustain
sequential node shutdowns to a single node.
The cluster-assigned dynamic vote of a node can be verified with the DynamicWeight common property of the cluster node by using the Get-ClusterNodeWindows
PowerShell cmdlet. A value of 0 indicates that the node does not have a quorum vote. A value of 1 indicates that the node has a quorum vote.
The vote assignment for all cluster nodes can be verified by using the Validate Cluster Quorum validation test.
Additional considerations
Dynamic quorum management does not allow the cluster to sustain a simultaneous failure of a majority of voting members. To continue running, the cluster must always have a quorum majority at the time of a node shutdown or failure.
If you have explicitly removed the vote of a node, the cluster cannot dynamically add or remove that vote.
Configure and Manage the Quorum in a Windows Server 2012 Failover Cluster
https://technet.microsoft.com/en-us/library/jj612870.aspx#BKMK_dynamic
Hope this info help you to reach your goal. :D
5ALU2 !

Windows 2008 Cluster question on using a new cluster drive source from shrinking existing disk

I have a two node Windows 2008 R2 enterprise SP1 cluster. It has a basic cluster setup of one (Q:)quorum disk and data disk (E:) which is 2.7tb is size. This cluster is connected to a shared Dell Disk array.
My question is can I safely shrink the 2.7tb drive down and carve out a disk size of 500gb from the same disk and use for a new cluster disk resource. We want to install Globalscape SFTP software on this new disk for use as a cluster resource.
Will this work without crashing the cluster.
Thanks,
Gonzolean

Hi ,
Thank you for posting your issue in the forum.
I am trying to involve someone familiar with this topic to further look at this issue. There might be some time delay. Appreciate your patience.
Thank you for your understanding and support.
Best Regards,
Andy Qi
Andy Qi
TechNet Community Support

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