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A cluster is defined as "a group of tightly coupled computers that work together closely so that in many respects they can be viewed as though they are a single computer" (per Wikipedia). A VMware ESX Cluster is no difference. Clusters are used for 3 things- 1) high availability, 2) load balancing, and 3) high performance computing. VMware ESX clusters are used for #1 and #2. With a VMware ESX Cluster, you define 2 or more physical machines that will provide resources for the hosts (or resource pools) that are assigned to that cluster. By using ESX clusters, you can achieve high availability (VM HA) and load balancing of virtual machines (called VMware DRS, discussed below) Just to reiterate, here is why you use VMware ESX Clusters: if one of the physical hosts goes down, the other physical host starts up the virtual guests machines that the original virtual host was running (VM HA). if one physical host is over utilized by a virtual guest, that virtual guest is moved to th

Console ports are not Ethernet ports All too often, new Cisco admins confuse Cisco's console port to be an Ethernet port. However, the console port on Cisco routers and switches is a SERIAL port (not Ethernet). That means that it is designed to connect to the COM port (serial port) on your PC. Although the cable that connects to it has an RJ45 on the end, just like an Ethernet cable, an Ethernet cable will not work to connect these two together. What you need is a serial "rolled cable" if you are going to directly connect the router to the PC. What's a Terminal Server? A "terminal server" is also called an access server. This is a device that commonly provides access FROM dumb terminals TO the network. However, you can turn this around and also use it to allow a single device to allow access TO the device, FROM the network. The most well known Cisco access servers are the 2509 and 2511. While these are discontinued models, they are still used today at many

Traffic Policing and Shaping Configuration Both the Traffic policing and Class-based traffic shaping features are implemented using the MQC. The MQC is used to classify traffic by defining a traffic class, set traffic policy by defining a traffic policy (where policing and shaping is implemented) and is assigned to a specific interface. Setting Up Traffic Classification The first step involves traffic classification setup; traffic that is matched to a specific class can have a number of different actions taken against it. For the purposes of this article, the action to be taken will be to police or shape the matched traffic.  Setting Up a Traffic Policy The second step involves traffic policy setup; the traffic policy is where specific actions can be configured. As stated before, in the context of this article, this is where the traffic policing and shaping are configured. Setting Up Assignment of the Configured Traffic Policy onto a Specific Interface The third step involv

Why do I need VMware Server Automatic Power up Options? Most commonly on a production server, you will want to power up VMware Server virtual machines when the server boots up. You don't want to have to remember to login to the server, start the VMware Server Console, then turn on the guest operating systems one by one. Plus, what if the server reboots in the middle of the night for some reason or another? All of those production virtual machines would be unavailable available until someone was alerted to power them on. Configure VMware Server Automatic Power up Options To configure VMware Server automatic power up motions for Virtual Guest OS systems, go to your VMware Server Console. Select the tab of the virtual machine that you want to configure the automatic power up options for. Click on  Edit Virtual Machine Settings , either on the Summary View for that Virtual Machine (VM) or by going to the VM Menu, then Settings. Once inside the VM Settings, click on the  Options  tab,

Windows 2000/2003 Active Directory domains utilize a Single Operation Master method called FSMO (Flexible Single Master Operation), as described in Understanding FSMO Roles in Active Directory. The five FSMO roles are: Schema master - Forest-wide and one per forest. Domain naming master - Forest-wide and one per forest. RID master - Domain-specific and one for each domain. PDC - PDC Emulator is domain-specific and one for each domain. Infrastructure master - Domain-specific and one for each domain. In most cases an administrator can keep the FSMO role holders (all 5 of them) in the same spot (or actually, on the same DC) as has been configured by the Active Directory installation process. However, there are scenarios where an administrator would want to move one or more of the FSMO roles from the default holder DC to a different DC. The transferring method is described in the Transferring FSMO Roles article, while seizing the roles from a non-operational DC to a different DC

It's true that by using a proper backup procedure it is possible to restore these objects. It's also true that you can use manual restore procedures such as the one in my Recovering Deleted Items in Active Directory article. However, I'm sure you'll gladly agree that it's best not to put yourself in that position in the first place. Luckily for us, in Windows Server 2008 and Windows Server 2008 R2, Microsoft has introduced a new option designed to protect Active Directory objects from being accidentally deleted. The option to protect objects from accidental deletion is available for all objects that are manageable through Active Directory Users and Computers (ADUC), and is enabled by default when you create a new OU. Let's see an example. I will create an OU and select the  "Protect container from accidental deletion" : Next, I will attempt to delete the object: As you can see, I failed to delete the object and received the following error message: So

The DHCP Relay Agent allows you to place DHCP clients and DHCP servers on different networks. Deploying DHCP in a single segment network is easy. All DHCP messages are IP broadcast messages, and therefore all the computers on the segment can listen and respond to these broadcasts. A single scope on a solitary DHCP server is all that is required. DHCP Messages on a Multisegment Network Things get a little more complicated when you have more than one subnet on your network. This is because the DHCP broadcast messages do not, by default, cross the router interfaces. There are several ways you can handle this situation. One alternative is to put a DHCP server on each segment. If you have just a few segments, you might consider this option. However, when you have a large organization, placing a DHCP server on each segment can increase cost and add to administrative effort. Relay To The Rescue A better option is to use fewer DHCP servers and place these machines in central locations. To sol

What is an Inventory?   An Inventory is the process of mounting media in the drive and reading the media label, which is then displayed in the  Devices  view. If this is the first time that Backup Exec (tm) has encountered this media, the media label is also added to the  Media  view.     Note : Each time new tape is introduced in the tape drive or robotic library, it must be inventoried so that the Backup Exec database gets updated with the new tape Information.     To Inventory a Tape/Robotic Library:   1. Insert the tape   2. Click the  Devices  tab   3. Select the correct tape drive/robotic library slot   4. Right-click on the tape drive/robotic library slot and select  Inventory  (Figure 1)   Figure 1   The inventory will complete and should display the correct tape name.   What is a Catalog?     When cataloging a tape, Backup Exec reads the header information from the tape and stores it in a file on the hard drive.   The information contained in the catalog i

You can add virtual disk units dynamically to a Linux® logical partition that uses IBM® i resources. This allows you to increase the storage capacity of your AIX® logical partition when needed. Virtual disks simplify hardware configuration on the server because they do not require you to add additional physical devices to the server in order to run Linux. You can allocate up to 64 virtual disks to a Linux logical partition. Each virtual disk supports up to 1000 GB of storage. Each virtual disk appears to Linux as one actual disk unit. However, the associated space in the i integrated file system is distributed across the disks that belong to the i logical partition. Distributing storage across the disks provides the benefits of device parity protection through i. Therefore, you do not have to use additional processing resources and memory resources by setting up device parity protection through Linux. IBM i provides the ability to dynamically add virtual disks to a Linux lo

An Overview of Repository Based Installation Linux distributions are essentially a collection of many different software packages combined with a Linux kernel. These packages are stored in repositories which may be accessed online to install and update Linux distributions. The key tools for performing these tasks on systems such as Red Hat Linux, Fedora and CentOS are called yum and rpm. Other Linux distributions (such as Debianand Ubuntu) use a different package management system which will be covered in Building a Debian or Ubuntu Xen Guest Root Filesystem using debootstrap. In terms of creating a Xen guest domain the yum and rpm tools can be used to install the base root filesystem on a blank disk image or partition by downloading the necessary packages from an online repository. This contrasts with the approach described in previous chapters whereby the root filesystem is simply copied from the host operating system Preparing to Create a Xen Guest Root Filesystem from R