December 6th, 2008 by Mithil

Hi

Their are lots of misunderstanding/confusion in Quorum Disk working and its size required.

I will try to sort out this Confusion in this discussion

This post will help, to understand those people who know what Cluster’s are. However, going in this discussion we must know how cluster work.

Cluster is a service which is used for Fault tolerance of an application, it is not for Load balancing as one server is in Active mode and others are in Passive mode. All resources are owned by one [Active] node in cluster. So when Active node is owner of resources it will serve all the request coming to it.

Now if this Active node goes down then all the services that this server is running will be transferred to other node [Passive], and then Passive node become Active  node.

Now how does the Passive node comes to know that Active node is down and I should start working as Active node.

Now here comes the involvement  of “Quorums Disk” .

When you configure Cluster for very first time, all Cluster configuration Database information are stored in this “Quorums Disk” in \MSCS\quolog.log. The quorum is also referred to as the quorum log. Quorums has to perform two most important jobs, those are, it lets the cluster service know which node should be active and be owner of resources. Node that is owner of the resources can only be in Active Mode. QUORUM is the main interpreter between all Nodes of cluster and help other node to take ownership when Active node goes down.

In some cases if internal communication of Cluster node fails, Say “Heart Beat” link goes down, Passive node will consider Active node has gown down, and start querying Quorum disk that Active node has gone down and request to transfer all the resources to him, but this is not the case as Active node is still functioning, so again Quorum disk play important role to reject Passive node request.

Disk size

Recommended Size is just 100mb, I would suggest to give 300-500mb.

Hope this post will help you

In my next post i will let know what pre-cluster node configuration to check before configuring Cluster.

November 12th, 2008 by Mithil

Step by Step Windows 2003 Cluster using VMware for testing Environment

It’s always good and must to have test environment rather than doing on live setup

Do I need to tell why?

Host System Installation

Windows 2003 SP2 Enterprise Edition with 4 GB RAM Dual Core 2 NIC [Minimum recommendation]

Do the OS installation as par the requirement, System drive 7 GB is enough

Update with SP2 and all latest patches

Install VMware server edition [Tested on version 5.x]

Installation and Configuration

Starting point is the preparation of a Windows 2003 cluster for Exchange 2003 with the following hardware specs.

ClusNode1 – System partition 4 Gb

ClusNode 2 – System partition 4 Gb

• Shared storage – Quorum – 500 Mb

• Shared storage – Databases – 4 Gb [Exchange Or SQL]

• Shared storage – Log files – 1 Gb [Exchange Or SQL ]

Two network interfaces (NICs) need to be configured per node, one for public cluster NIC and another for private NIC will be used for cluster heartbeat.

If you have AD/Domain installed on your test environment else install AD/Domain controller for testing environment then create cluster account or and create account with setting “Password never Expire” and “password can not be changed”.

Start Vmware Virtual machine creation

Create new virtual machine

Guest OS can be installed on Virtual IDE drive created in VMware

Open new Virtual machine Wizard

NEXT

Choose Custom >> click NEXT

Select Windows 2003 Ent >> Click NEXT

Give Friendly name to your Virtual Machine and its location [Store it on diff partition other that system]

Click Next.

On next page, allocate RAM memory to 1 GB [Recommended]

For Network type select Bridge Networking, click next

[This NIC will be used for public Access]

Create Virtual Machine Disk, Click NEXT.

Give Disk Capacity, I recommend 4-5 GB Click Next

Give the location where virtual disk information would be store

[This is the file that we will need to edit for sharing disk resource]

Click Advance

Select IDE 0.1, [This is the disk on which Virtual machine’s OS will be installed].

Click Finish.

Now additional component need to be added, like second NIC, and 2 SCSI HDD as shared disk resource.

Now click on “edit virtual machine setting”

Add >click “NEXT” on next page

Select Hard Disk click “NEXT”

Select option “Create New virtual disk”

Give disk space 500mb only

Specify this disk as Quorum disk

Click on “Advance”

Select SCSI 0:0 as Virtual Device Node and click on ‘Finish’.

Repeat the steps above for the remaining shared disks, those are needed.

Be Aware! The shared disks must be added as SCSI as this is necessary for the correct functioning of MSCS.

Now an extra NIC is needed.

Do same processes mention above, but select Ethernet Adapter on both VM’s

Select “Host-Only” click finish

This NIC will be used for “Hertbeat”

Complete configuration must look like this

Click on ‘OK’ to close the configuration editor.

Start Windows Explorer and navigate to the folder where the Virtual Machine is created.

Example it is Z:\VMware virtual machines\clusternodeA\name .vmx).

Open with Notepad the file <vm name>.vmx and add at the end the following line:

Disk.locking = FALSE

This makes sure that both nodes can access the same disks at the same time in case of cluster failover. MSCS is intelligent enough to prevent that both nodes actually do this at the same time.

Using the VMWare SCSI Driver in a New Virtual Machine

To use the driver when you are installing a Windows Server 2003 or Windows XP guest operating system in a newly created virtual machine, follow these steps. Download the driver from hxxp://www.vmware.com/download/downloadscsi.html

Save the downloaded file — vmscsi_<xxxx>.flp

Now the SCSI Hard-Disk those were added need to be configured

Edit the virtual machine configuration, click on added SCSI HDD and change the setting as shown below.

Make same changes to remaining SCSI hard-disk only. Virtual device node must me SCSI 0.1 as it would be another SCSI Device

Start the VM installation one by one [not simultaneously it will cause corrupt the hard-disk and shared data. Same precaution must be taken whenever Cluster node is rebooted.

Now you are ready to install cluster service on newly installed VM.

September 26th, 2008 by Gabriel

Windows is a operating system sold by company Microsoft. Microsoft is a Seattle-based company.
Initially its name was “Traf-O-Data” which is renamed to Microsoft on November 26, 1976.
First release of Operatin System in August 1981 was Microsoft DOS 1.0 which is a 16-bit command-line operating system.
November 1985 was the month of invention of first graphical user interface OS.

Following is the version history in short -

1. Windows 1.0 - 1985
2. Windows 2.0 - 1987
3. Windows 3.0 - 1990
4. Windows 3.1 - 1992
5. Windows NT - 1992
6. Windows NT 3.1 - 1993
7. Windows NT 3.5 - 1994
8. Windows 95 - 1995
9. Windows NT 4.0 - 1996
10. Windows 98 - 1998
11. Windows 2000 - 2000
12. Windows ME - 2000
13. Windows XP - 2001
14. Windows 2003 - 2003