My IT Blog

We get an enormous amount of questions about VMware’s HA (High Availability), especially when users see a message stating there are Insufficient resources to satisfy HA failover. We have already discussed the mechanism that HA uses to provide high availability here . Now we need to understand capacity calculations. In current versions of ESX (3.02) and earlier the following calculation applies for failover capacity. HA Failover Capacity Failover Capacity is determined using a slot size value that is calculated on the cluster. Slots are calculated by a combination of the total CPU and Memory that are in the physical hosts. The calculation for failover capacity works as follows: Let’s say you have 4 ESX servers in your VMware HA cluster and Configured Failover capacity on the cluster is set to 1. Physical memory in the hosts is as follows: ESX1 = 16 GB ESX2 = 24 GB ESX3 = 32 GB ESX4 = 32 GB In the cluster you have 24 VM’s each configured and running. Of the 24 VM’s run

Linux - Ubuntu 8.04 Server I am not going to go through each and every step of the Ubuntu installation as that is really straight forward. I downloaded the 8.04 Server version from http://www.ubuntu.com/getubuntu/download and started the installation one on of the nodes. During disk partitioning, select manual mode and delete any existing partitions (if there are any). Create one partition for your main system and make it 5GB. This partition will be used for your Dom0 and 5GB should be more than enough. Create a second partition for your swap for Dom0. Make this 512MB as we later will configure Dom0 to use 512MB of RAM. Create a third partition with all your remaining space. At the packages selection step do not select any packages. Leave everything deselected. A few minutes later you should have a basic installation of Ubuntu 8.04 Server running. Ubuntu - Base configuration A few things need to be done to the freshly installed Ubuntu Server before we start installing

Assigning a virtual IP to a NIC is a very easy task either you use the system-config-networktool or just do some text file editing. The script ifconfig can also be used to create a virtual network interface, but this would not be permanent since the changes ifconfig makes do not survive a reboot. In this post I’ll stick with the “manual” way… In Fedora, all information about the network interfaces is kept in the following directories: /etc/sysconfig/network-scripts/ /etc/sysconfig/networking/ I assume that the default NIC configuration script is: /etc/sysconfig/network-scripts/ifcfg-eth0. Mine looks like this:DEVICE=eth0 BOOTPROTO=static BROADCAST=192.168.0.255 HWADDR=00:00:00:00:00:00 IPADDR=192.168.0.1 NETMASK=255.255.255.0 NETWORK=192.168.0.0 ONBOOT=yes TYPE=Ethernet GATEWAY=192.168.0.254 BOOTPROTO: sets the protocol that is used when the device is initialized. Since we use static IPs we set it to static. HWADDR: is the MAC address of your network card. Do not change it

An Overview on Folder Redirection Folder Redirection is a Group Policy feature that enables users to redirect the system folders containing the profile of a user on the network, through the use of the Folder Redirection node in the Group Policy Object Editor console. This basically makes folder redirection a user configuration option. Through the use of the Folder Redirection feature, users can configure that the system folders’ contents on the user remains the same, irrespective of the particular computer used to log onto the system. The system folders that users can configure for folder redirection are listed below: Application Data: This folder contains user configuration files, user specific data that applications utilize, and Public Key Infrastructure files. Desktop: This folder holds the shortcuts and files that appear on the user’s desktop. My Documents: This folder holds the user’s files and pictures. Start Menu: This folder holds the shortcuts and files that appear on

Understanding the Different Server Roles The server roles that exist in a networking environment are standalone servers, member servers and domain controllers. A standalone server is a computer that is not member of a domain, and can be a computer running Windows NT 4, Windows 2000 or Windows Server 2003. A test server is a good example of a standalone server. Standalone servers do not use Active Directory for authentication and access control because they are not included in the Active Directory domain. These servers use the local Security Accounts Manager (SAM) database on the local machine for access control. A member server is a machine that holds a replica of the Active Directory data store, and is a member of the domain, but it does not perform any domain management functions. Because a member server operates as a member of the domain, it has a computer account within the domain. Users and computers can be authenticated and managed via the domain. Member servers are your pri

Domains and Forests A domain in Active Directory consists of a set of computers and resources that all share a common directory database. Domains contain all the objects that exist in the network and can store a multitude of objects. Each domain contains information on the objects that they contain. A domain is also a security boundary. Domain trees are created by adding child domains to a parent domain. Domains that are grouped into a domain tree have a hierarchical naming structure and also share a contiguous namespace. A forest is the grouping of one or multiple domain trees. Domains in a forest share a common schema and global catalog, and are connected by two-way transitive trusts. Domains in a forest function independently, with the forest making communication possible with the whole organization. Installing Domain Controllers – domains Because domains can only exist with a domain controller, you need to create a domain controller(s). When you create the first domain c

An Overview on Performance Monitoring and Management Performance monitoring is the process of accurately and consistently measuring performance, so that you can identify any potential bottlenecks which may be impairing the way in which Active Directory performs within your environment. A bottleneck can take place on any Windows subsystem or network component, and occurs when one resource prevents a different resource from operating optimally. Incorrectly configured settings or the insufficient distribution of resources between network components can result in bottlenecks occurring. Monitoring performance can be considered the initial step in defining any performance optimization strategy for your network or network resources. Before you can optimize performance, you have to identify and eliminate existing bottlenecks, or potential bottlenecks. There are a few system and network monitoring tools provided by Windows Server 2003, which can be used to monitor Active Directory performa