windows cluster question and

8/12/2019 Windows Cluster Question And

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Windows Cluster Question and Answer

What is Clustering. Briefly define & explain it ?

Clustering is a technology, which is used to provide High Availability for mission critical

applications. We can configure cluster by installing MCS (Microsoft cluster service componentfrom Add remove programs, which can only available in !nterprise !dition and "ata center

edition.

>Types of Clusters ?

#n Windows we can configure two types of clusters

1. NB(networ$ load balancing cluster for balancing load between servers. %his cluster will not

provide any high availability. &sually preferable at edge servers li$e web or pro'y.

!. "er#er Cluster$%his provides High availability by configuring activeactive or activepassive

cluster. #n ) node activepassive cluster one node will be active and one node will be stand by.When active server fails the application will *A#+-! to stand by server automatically. When

the original server bac$s we need to *A#+/AC0 the application

> What is Quoru% ?A shared storage need to provide for all servers which $eeps informationabout clustered application and session state and is useful in *A#+-! situation. %his is very

important if 1uorum dis$ fails entire cluster will fails.

>Why Quoru% is neessary ?

When networ$ problems occur, they can interfere with communication between cluster nodes. A

small set of nodes might be able to communicate together across a functioning part of a networ$,but might not be able to communicate with a different set of nodes in another part of the networ$.

%his can cause serious issues. #n this 2split3 situation, at least one of the sets of nodes must stop

running as a cluster.

%o prevent the issues that are caused by a split in the cluster, the cluster software re4uires thatany set of nodes running as a cluster must use a voting algorithm to determine whether, at a

given time, that set has 4uorum. /ecause a given cluster has a specific set of nodes and a specific

4uorum configuration, the cluster will $now how many 2votes3 constitutes a ma5ority (that is, a4uorum. #f the number drops below the ma5ority, the cluster stops running. 6odes will still listen

for the presence of other nodes, in case another node appears again on the networ$, but the nodes

will not begin to function as a cluster until the 4uorum e'ists again.

*or e'ample, in a five node cluster that is using a node ma5ority, consider what happens if nodes7, ), and 8 can communicate with each other but not with nodes 9 and :. 6odes 7, ), and 8

constitute a ma5ority, and they continue running as a cluster. 6odes 9 and : are a minority and

stop running as a cluster, which prevents the problems of a 2split3 situation. #f node 8 losescommunication with other nodes, all nodes stop running as a cluster. However, all functioning


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nodes will continue to listen for communication, so that when the networ$ begins wor$ing again,

the cluster can form and begin to run.

; 'ifferent types of Quoru% in Windows ser#er !(() ?

7.6ode Ma5ority < &sed when dd number of nodes are in cluster.).6ode and "is$ Ma5ority < !ven number of nodes(but not a multisite cluster

8.6ode and *ile Share Ma5ority < !ven number of nodes, multisite cluster

9.6ode and *ile Share Ma5ority < !ven number of nodes, no shared storage

> 'ifferent types of Quoru% in Windows ser#er !((* ?

"tandard Quoru% $ As mentioned above, a 4uorum is simply a configuration database for

MSCS, and is stored in the 4uorum log file. A standard 4uorum uses a 4uorum log file that is

located on a dis$ hosted on a shared storage interconnect that is accessible by all members of thecluster.

Standard 4uorums are available in Windows 6% 9.= !nterprise !dition, Windows )===

Advanced Server, Windows )=== "atacenter Server, Windows Server )==8 !nterprise !ditionand Windows Server )==8 "atacenter !dition.

+a,ority Node "et Quoru%s $A ma5ority node set (M6S 4uorum is a single 4uorum resource

from a server cluster perspective. However, the data is actually stored by default on the system

dis$ of each member of the cluster. %he M6S resource ta$es care to ensure that the clusterconfiguration data stored on the M6S is $ept consistent across the different dis$s.

Ma5ority node set 4uorums are available in Windows Server )==8 !nterprise !dition, and

Windows Server )==8 "atacenter !dition.

>-xplain aout eah Quoru% type ?

6ode Ma5ority> !ach node that is available and in communication can vote. %he cluster functionsonly with a ma5ority of the votes, that is, more than half.

6ode and "is$ Ma5ority> !ach node plus a designated dis$ in the cluster storage (the 2dis$

witness3 can vote, whenever they are available and in communication. %he cluster functionsonly with a ma5ority of the votes, that is, more than half.

6ode and *ile Share Ma5ority> !ach node plus a designated file share created by the

administrator (the 2file share witness3 can vote, whenever they are available and in

communication. %he cluster functions only with a ma5ority of the votes, that is, more than half.

6o Ma5ority> "is$ nly> %he cluster has 4uorum if one node is available and in communicationwith a specific dis$ in the cluster storage.

> /ow is the 0uoru% infor%ation loated on the syste% dis of eah node ept in synh?

%he server cluster infrastructure ensures that all changes are replicated and updated on all

members in a cluster.


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> Can this %ethod e used to repliate appliation data as well?

6o, that is not possible in this version of clustering. nly 1uorum information is replicated and

maintained in a synchroni?ed state by the clustering infrastructure.

> Can 2 on#ert a standard luster to an +N" luster?

@es. @ou can use Cluster Administrator to create a new Ma5ority 6ode Set resource and then, on

the cluster properties sheet Quoru%tab, change the 4uorum to that Ma5ority 6ode Set resource.

> What is the differene etween a geographially dispersed luster and an +N" luster?

A geographic cluster refers to a cluster that has nodes in multiple locations, while an M6Sbased

cluster refers to the type of 4uorum resources in use. A geographic cluster can use either a shareddis$ or M6S 4uorum resource, while an M6Sbased cluster can be located in a single site, or

span multiple sites.

> What is the %axi%u% nu%er of nodes in an +N" luster?

Windows Server )==8 supports node clusters for both !nterprise !dition and "atacenter!dition.

> 'o 2 need speial hardware to use an +N" luster?

%here is nothing inherent in the M6S architecture that re4uires any special hardware, other than

what is re4uired for a standard cluster (for e'ample, there must be on the Microsoft Cluster

HC+. However, some situations that use an M6S cluster may have uni4ue re4uirements (such

as geographic clusters, where data must be replicated in real time between sites.

> 'oes a luster aware appliation need to e rewritten to support +N"?

6o, using an M6S 4uorum re4uires no change to the application. However, some cluster aware

applications e'pect a shared dis$ (for e'ample S1+ Server )===, so while you do not needshared dis$s for the 4uorum, you do need shared dis$s for the application.

> 'oes +N" get rid of the need for shared diss?

#t depends on the application. *or e'ample, clustered S1+ Server )=== re4uires shared dis$ for

data. emember, M6S only removes the need for a shared dis$ 4uorum.

> What does a failo#er luster do in Windows "er#er !(() ?

A failover cluster is a group of independent computers that wor$ together to increase the

availability of applications and services. %he clustered servers (called nodes are connected by

physical cables and by software. #f one of the cluster nodes fails, another node begins to provideservice (a process $nown as failover. &sers e'perience a minimum of disruptions in service.


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> What new funtionality does failo#er lustering pro#ide in Windows "er#er !(() ?

6ew validation feature. With this feature, you can chec$ that your system, storage, and networ$

configuration is suitable for a cluster.

Support for B" partition table (B% dis$s in cluster storage. B% dis$s can have partitions

larger than two terabytes and have builtin redundancy in the way partition information is stored,unli$e master boot record (M/ dis$s.

> What happens to a running Cluster if the 0uoru% dis fails in Windows "er#er !((*

Cluster ?

#n Windows Server )==8, the 1uorum dis$ resource is re4uired for the Cluster

to function. #n your e'ample, if the 1uorum dis$ suddenly became unavailableto the cluster then both nodes would immediately fail and not be able to

restart the clussvc.

#n that light, the 1uorum dis$ was a single point of failure in a Microsoft

Cluster implementation. However, it was usually a fairly 4uic$ wor$around toget the cluster bac$ up and operational. %here are generally two solutions

to that type of problem.

7. "etemrine why the 1uorum dis$ failed and repair.

). eprovision a new +&6, present it to the cluster, assign it a driveletter and format. %hen start one node with the D*1 switch and through

cluadmin designate the new dis$ resource as the 1uorum. %hen stop and

restart the clussvc normally and then bring online the second node.

; What happens to a running Cluster if the 4uorum dis$ fails in Windows Server )== Cluster E

Cluster continue to wor$ but failover will not happen in case of any other failure in the activenode.

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