Saturday, August 22, 2015

Microsoft Clustering

                                       Microsoft Clustering:

It is used for high availability for critical applications.

There are two types of Microsoft Clustering.
(a)    Failover Clustering
(b)   Network Load Balancer

Failover Clustering: 
Windows server failover clustering (WSFC) is a feature of the Windows server platform for improving the high availability of applications and services.

Failover Clustering types:
Active-Active & Active- Passive

There are two types of applications also.
Cluster aware applications, examples- SQL, Java, .Net, Exchange etc.
Cluster unaware applications, examples- IIS, VPN, Proxy etc.

Two Node Microsoft clustering requirements (Windows Server 2003):-
1.       Two servers with same Hardware configuration along with same Operating system.
2.       2 NIC’s in each Nodes (1st- Prod and 2nd – Heartbeat)
3.       5 IP addresses: 2 for LAN (Prod IP- 10.10.10.5 & 10.10.10.6), 2 for Heartbeat (Local IP- 20.20.20.1 & 20.20.20.2) and 1 for Clustering (Public IP- 10.10.10.100)
4.       Both Node should be part of Domain. (Member Servers)
5.       Two Domain users (A- For cluster configuration and B- for run cluster service) and B password will set to never expire. Both user should have local admin rights on both Nodes. (Node 1 and Node 2)
6.       We have to create a Host A record in the name of Cluster in DNS line SQLcluster and IP should be public. (Example- 10.10.10.100)
7.       We have to create a Computer account in Active Directory Users and Computers with name of Cluster (SQLcluster) and give full permission to both Domain users (A and B) then disable this computer account.
8.       We have to create a 1GB disk for Quorum (Circle Box in below picture) to save cluster configuration and this disk will appear on both Nodes but only Active node will access this drive.

Start the configuration (Below mentioned):







 Domain Controller & DNS server (10.10.10.1), Host A (SQLcluster) in DNS -10.10.10.100
 





           Switch










Node1                                                                                                                               Node 2

                                                                                                                                                                                                                                                   









Note: Microsoft cluster configuration is similar for both Server 2003 and Server 2008 however there are few points which is essential to know before start the configuration:
Ø  We need to download and install iScsi initiator in Windows server 2003 server but in 2008 it is inbuilt, we just need to enable it.
Ø  Two user account required in Windows 2003 server for cluster configuration and start the cluster service but in 2008 server only one user account required.

Windows 2008 cluster configuration same as 2003 (1 user [local account] for cluster configuration and start the service): {2-Node Microsoft Cluster}

Login on both Node (Node 1 and Node 2) from user (A- To configure cluster and start the service).
Open Server Manager- Features- Add features- Failover clustering- Next- Install on both Node 1 and Node 2.
Start- Programs- Administrative Tools- Failover clustering Manager- Validate configuration-Next- Browse – Node 1 & Node 2- Add
(It will test the configuration which includes following tasks:
Inventory tasks, Network test, Storage test and system configuration test.
It will generate a report for all these test in HTML format.)
-          Run all the tasks (Recommended)- Next-next- View detais report- Next

Click on create a cluster

On Node 1
Failover cluster- Create- Add user cluster- Next

On Node 1

Add Node- Next- Next- browse- Advanced-find now -Next-Add- Next

Go to on Node 2 and check failover clustering.


Difference between 2K3 and 2K8 clustering:

1.       Windows 2003 cluster service run by Domain user account but in 2K8 by local account.
2.       Windows 2K3 sends information to Heartbeat partner locally after every 1.2 seconds but in Windows server 2K8 it sends after every 1 seconds.
3.       Communication will fail if Windows 2K3 server won’t receive response from partner in 6 seconds however in 2K8 it changed to 5 seconds.
4.       Quorum disk used for storage in 2K3 but same is known as Witness disk in 2K8.
5.       In windows 2K3 cluster configuration file report is .log format but in 2K8 it is .HTML format.
6.       In windows 2K3 Quorum is a single point of failure but in 2K8 Quorum woks on majority system.
7.       Windows 2K3 works on single VLAN but Windows 2K8 works on multiple VLAN.
8.       Windows 2K3 supports 8-Node Microsoft cluster but 2K8 supports 16-Node Microsoft cluster.
Quorum Majority system in Windows 2K8:
(A)   Node majority
(B)   Node and Disk majority
(C)   Node and File share majority
(D)   No majority. Disk only

Quorum configuration choices
You can choose from among four possible quorum configurations:
  • Node Majority (recommended for clusters with an odd number of nodes)

    Can sustain failures of half the nodes (rounding up) minus one. For example, a seven node cluster can sustain three node failures.
  • Node and Disk Majority (recommended for clusters with an even number of nodes)

    Can sustain failures of half the nodes (rounding up) if the disk witness remains online. For example, a six node cluster in which the disk witness is online could sustain three node failures.

    Can sustain failures of half the nodes (rounding up) minus one if the disk witness goes offline or fails. For example, a six node cluster with a failed disk witness could sustain two (3-1=2) node failures.
  • Node and File Share Majority (for clusters with special configurations)

    Works in a similar way to Node and Disk Majority, but instead of a disk witness, this cluster uses a file share witness.

    Note that if you use Node and File Share Majority, at least one of the available cluster nodes must contain a current copy of the cluster configuration before you can start the cluster. Otherwise, you must force the starting of the cluster through a particular node.
  • No Majority: Disk Only (not recommended)

    Can sustain failures of all nodes except one (if the disk is online). However, this configuration is not recommended because the disk might be a single point of failure.
Visit Microsoft Tech Net website for more information: