Lesson Five: Domain Name System (DNS)

This week’s lesson focused on the Domain Name System (DNS).  It was a very useful primer on how DNS works and how to configure Windows Server 2008 and Server 2012 as DNS servers.  I was very interested by the information on name resolution and Internet root servers in particular.  We were shown how to forward DNS requests to other machines that might be authoritative, and how to handle name resolution within a private intranet.

We then learned about DNS zone management, including primary, secondary and stub zones and the advantages and disadvantages of each.  If you are able to run a DNS sever as a domain controller, they you can designate the zone as an Active Directory Integrated zones.  This allows zone transfers to be made with encrypted data.  Next, we covered how to create reverse lookup zones and then the types of records that can be added for different purposes.  Very useful information when trying to keep untrusted people and machines away from your data.

The lesson closed with information on DNS troubleshooting, including the relevant commands as well as best practices.  This module has given me a more comprehensive view of the purposes and functions of the DNS system as implemented in Windows Server operating systems.

Lesson Four: Active Directory

This week’s lesson in the Windows Server Pro certification curriculum focused on Active Directory. This agent allows organizational resources to be effectively deployed and managed.  This is accomplished by the use of a server call the Domain Controller.  These machines use Organizational Units (OU) to hold resources of users and hardware to accomplish the organization’s mission while making sure that corporate security and access needs are met.

An OU is a generic container that can hold users or groups of users as well as computers or other resources. It is the smallest unit that can be assigned Group Policy settings or that can be delegated administrative authority.  OU's should reflect a domain structure that closely reflects the design of the organization.     

This was an useful lesson, looking forward to more!

Lesson Three: Hyper-V

This week we focused on using Windows Server’s ability to create and use virtual machine, which is known as Hyper-V.  In Hyper-V, Windows can simulate virtual machines, which can then be configured to do any task that can be accomplished by a physical server.  This server virtualization allows the virtual servers to extend access to the resources on a network.

By using virtual machines, Windows can stretch the physical limits of any available resources.  TO take an example, if you have a 10 GB physical hard disk, virtual machine 1 and virtual machine 2 can each see those 10 GB and call it their own, thereby making it seem like Windows has 20 GB of disk storage available.  It is a good strategy to extend processor cores, system memory and storage space among many competing priorities.

These lesson on server virtualization interested me greatly - I'm looking forward to much more to come!

Lesson Two: Hardware Management

This week we learned about the installation of Windows Server 2012.  It was a pretty wide-ranging lesson, from how, when and why to implement the three types of user interface from a full Windows experience with Internet Explorer included; a GUI of server management tools; or command line access only.

Control of a server using Windows Power Shell commands from a command line only obviates the need for a graphical interface using up precious clock cycles and closes potential server vulnerabilities by avoiding the use of a graphical interface.  This type of installation is knows as Server Core.

We also learned a lot about the modern tools available in the re-thought Windows Server 2012.  NIC teaming allows an administrator to gang each interface together to either aggregate performance or provide failover capabilities for each interface.

The training course also covered the usage of storage devices and how to connect and install them on the server.  While they went into great depth to cover the ability of the operating system to provide the traditional types of software RAID arrays of mirroring, striping and parity to provide different types of volumes.  These can be easily understood:

A simple volume is a single and contiguous block of space of a single hard drive.  There is no failover tolerance in this mode, i.e., any hard drive dying loses all data on it.

A spanned volume combines areas from two or more disks into one unit.  This has the advantages of combining scraps of space the might otherwise go unused, but like the simple volume provides no protection against hardware failure.

A striped volume breaks data into units and then stores those units across various disk drives that are available to the system.  This can be set up on two or more disks as long as the size of the partition on each disk is the same.  This provides an increase in performance but no fault toleration.  The acronym RAID 0 applies to this type of volume.

A striped volume with parity acts much like the striped volume above, but adds parity information to each drive used.  This has the benefit that data can be recovered by the combination of the existing data with the existing parity information surviving on the non-failed devices to recreate the dataset across all devices in the array.  This type of array is analogous to RAID 5.

The mirrored volume stores two copies of each file on two different disk drives.  This has the effect of halving storage capacity, but provides fault toleration in case of hardware failure.  This type of array is also known as RAID 1.

Having gone into some length about this, the instructor then dropped the bombshell that a sysadmin most likely would rarely if ever use this software RAID implementation to manage hard drives.  A new tool, Storage Pools, helps the system administrator to aggregate available storage devices or at the same time provide failover services.  This more closely mimics traditional hardware RAID services, but is more flexible and does not usually require the admin to configure each device separately.

Likewise, server aggregation or failover tolerance is provided by the tool Server Pool.  This allows the admin to pool servers in groups, and then administer the group as if they were working on an individual machine.  Server groups, or Pools, can then be tasked with server roles and features.

A tool that interested me extremely is Windows RM, or Remote Manager.  Windows RM allows an administrator to push commands in real time to another server (or any joined machine) on the workgroup or domain.  The advantage of this is that any command that can be given from the command line can be immediately sent to the remote system without requiring a reboot.

There are many more features that I am not able to cover in this brief synopsis such as virtual hard disks and Server 2012's ability to import and export disks and servers.

This week was an overwhelming but exhilarating introduction to Windows Server 2012.  I'm looking forward to next week's lesson!