Home > Articles > Operating Systems, Server > Microsoft Servers

This chapter is from the book

This chapter is from the book

Improvements in Clustering and Storage Area Network Support

Although clustering of servers has been around for a long time in Windows (dating back to Windows NT 4.0 when it was available, but really didn't work), clustering in Windows 2008 now not only works, but also provides a series of significant improvements that actually make clustering work a whole lot better.

As IT administrators are tasked with the responsibility of keeping the network operational 24 hours a day, 7 days a week, it becomes even more important that clustering works. Fortunately, the cost of hardware that supports clustering has gotten significantly less expensive; in fact, any server that meets the required specifications to run Windows Server 2008, Enterprise Edition can typically support Windows clustering. The basic standard for a server that is used for enterprise networking has the technologies built in to the system for high availability. Windows Server 2008, Enterprise Edition or Datacenter Edition is required to run Windows 2008 clustering services.

Clustering is covered in detail in Chapter 29, "System-Level Fault Tolerance (Clustering/Network Load Balancing)."

No Single Point of Failure in Clustering

Clustering by definition should provide redundancy and high availability of server systems; however, in previous versions of Windows clustering, a "quorum drive" was required for the cluster systems to connect to as the point of validation for cluster operations. If at any point the quorum drive failed, the cluster would not be able to failover from one system to another. Windows 2008 clustering removed this requirement of a static quorum drive. Two major technologies facilitate this elimination of a single or central point of failure, which include majority-based cluster membership verification and witness-based quorum validation.

The majority-based cluster membership allows the IT administrator to define what devices in the cluster get a vote to determine whether a cluster node is in a failed state and the cluster needs to failover to another node. Rather than assuming the disk will always be available as in the previous quorum disk model, now nodes of the cluster and shared storage devices participate in the new enhanced quorum model in Windows 2008. Effectively, Windows 2008 server clusters have better information to determine whether it is appropriate to failover a cluster in the event of a system or device failure.

The witness-based quorum eliminates the single quorum disk from the cluster operation validation model. Instead, a completely separate node or file share can be set as the file share witness. In the case of a GeoCluster where cluster nodes are in completely different locations, the ability to place the file share in a third site and even enable that file share to serve as the witness for multiple clusters becomes a benefit for both organizations with distributed data centers and also provides more resiliency in the cluster operations components.

Stretched Clusters

Windows 2008 also introduced the concept of stretched clusters to provide better server and site server redundancy. Effectively, Microsoft has eliminated the need to have cluster servers remain on the same subnet as has been the case in Windows clustering in the past. Although organizations have used virtual local area networks (VLANs) to stretch a subnet across multiple locations, this was not always easy to do and, in many cases, technologically not the right thing to do in IP networking design.

By allowing cluster nodes to reside on different subnets, plus with the addition of a configurable heartbeat timeout, clusters can now be set up in ways that match an organization's disaster failover and recovery strategy.

Improved Support for Storage Area Networks

Windows 2008 also has improved its support for storage area networks (SANs) by providing enhanced mechanisms for connecting to SANs as well as switching between SAN nodes. In the past, a connection to a SAN was a static connection, meaning that a server was connected to a SAN just as if the server was physically connected to a direct attached storage system. However, the concept of a SAN is that if a SAN fails, the server should reconnect to a SAN device that is now online. This could not be easily done with Windows 2003 or prior. SCSI bus resets were required to disconnect a server from one SAN device to another.

With Windows 2008, a server can be associated with a SAN with a persistent reservation to access a specific shared disk; however, in the event that the SAN fails, the server session can be logically connected to another SAN target system without having to script device resets that have been complicated and disruptive in disaster recovery scenarios.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020