Search
Related Links

 

 

Informative Articles

Data backups are the biggest security threats!
Gary, a network security consultant with Fortune 500 companies, and an editor of data-recovery-reviews.com argues that data backups actually hinder corporate IS security and makes a case for offsite backups. Gary J, security consultant of the ...
Disaster Planning ¡V How important is it to you!
I have been extracting Marketing Case Studies from Jim Aitchison¡¦s ¡§How Asia Advertises¡¨ for the past six issues. Frankly speaking, I am a bit sick of it. Having to extract articles from one source and post it onto the newsletters. Oh man, time...
Disaster Recovery More Than Meets The Eye
As the Vice President of Operations for an online retailer of contact lenses, I am used to the potential problems related to doing business on the World Wide Web. Like any other online retailer, we have a responsibility to our customers to maintain...
Do I Really Need to Backup?
Do I Really Need To Backup? by Keith Thompson Okay, computers a machine, right? Okay, maybe not yours. You have this special relationship, but that a subject for another article. Machines break. Software gets fouled up. People make...
Loans For Bad Debtors: Discarding Debt Disorganization To Recover Financial Growth
Debt disorganization can often lead you to challenges like being permanently tagged as bad debtor. Your personal economy has many repercussions of such a scenario, especially when you are trying to get through the market of debt. Loans for bad...
 
Webfarms II: Balancing The Load.

Okay, so you understand webfarms now. What's the magic that actually distributes the load, and how does it determine how the distribution is handled?

At ORCS Web we use the Foundry Server Iron products to perform our webfarm load-balancing. If one of them fails, the other instantly takes over (In our testing, it had sub-second fail-over!)

So what is this "Server Iron" thing? In simplest terms, it's a layer 4-7 switch. It has multiple network ports on it and can be used literally like other types of switches. But, it can also load-balancing and traffic distribution. A VIP (virtual IP) can be assigned to the SI (Server Iron) and it then handles all traffic sent to that address/VIP. Further configuration is done to tell the SI what to actually do with the traffic sent to the VIP address.

The traffic that hits the VIP on the Server Iron is of course redistributed to a number of server nodes so the client request can be satisfied - that's the whole point of a webfarm. If one or more server nodes are not responding, the switches are able to detect this and send all new requests to servers that are still online - making the failure of a server node almost transparent to the client.

The traffic can be distributed based on a couple different logic algorithms. The most common are:

* Round Robin: The switches send requests to each server in rotation, regardless of how many connections each server has or how fast it may reply.

* Fastest response: The switches select the server node with the fastest response time and sends new connection requests to that server.

* Least connections: The switches send traffic to whichever server node shows as having the fewest active connections.

* Active-passive: This is called Local/Remote on a Foundry switch, but is still basically active/passive. This allows one or more servers to be designated as "local" which marks them as primary for all traffic. This is combined with


another method above to determine what order the "local" server nodes have requests sent to them. If a situation were to arise that all the "local" (active) server nodes were down, then traffic would be sent to the "remote" server nodes. Note that "remote" in this case doesn't really have to mean remote - the "remote" server could be sitting right next to the "local" servers but it is marked as remote in the configuration to let it operate as a hot-standby server. This setting can also be used in a true remote situation where there are servers in a different physical data center - perhaps for extreme disaster recovery situations.

What method is best? It really depends on your application and some other surrounding factors. Each method is good though and would probably satisfy requirements regardless of the configuration. Especially if you are closely monitoring each server node with an external tool (other than directly from the load-balancing switch). So, with the external monitoring you can confirm that all server nodes are operating without error and within reasonable speed thresholds that have been set.

Also, remember that, regardless which traffic algorithm is chosen, if a node goes down, traffic is sent to the other nodes. And when a node comes back online, it can automatically be placed back into the webfarm and start getting client requests again.

Clustered hosting does require some consideration of how state is managed within applications, which will be covered in a future article.

Happy hosting!

~Brad

Brad Kingsley is President and Founder of ORCS Web, Inc. - a company that provides managed hosting services for clients who develop and deploy their applications on Microsoft Windows platforms.

About the Author

Brad Kingsley is President and Founder of ORCS Web, Inc. - a company that provides managed hosting services for clients who develop and deploy their applications on Microsoft Windows platforms.

 

Data Recovery Software and Undelete from R-TT
Disk management software including utilities for data recovery, drive imaging, disk wiping and access control.
www.r-tt.com
 
Data Recovery | Email Data Recovery by Ontrack
Data recovery services, data recovery software, file repair software, and diagnostic software from Ontrack. Software for email recovery, file recovery and ...
www.ontrack.com
 
Data Recovery by DriveSavers | Hard Drive Data Recovery
Worldwide data recovery service for all operating systems and storage media. Authorized by all drive manufacturers.
www.drivesavers.com
 
Hard Drive Data Recovery Software Tools, Disk Recovery Utilities ...
Offers data recovery software,data recovery services for hard drive recovery and data safety software services for your computer. Buy award winning data ...
www.stellarinfo.com
 
Data Recovery by FADV – Hard Drive, RAID, Tape, Database and more ...
Offers data recovery services for all hard drive models. RAID, MS SQL, Exchange, Tapes, Camera and USB media, CD and DVD. Service available 24/7.
www.datarecovery.net
 
Data Recovery Software - File System Utilities
Data recovery software for all Windows file systems. Recover deleted files, corrupted hard drives, and partitions.
www.runtime.org
 
Professional Data Recovery Software from Bitmart. File Recovery ...
Data Recovery Software Restorer2000. Undelete & File Recovery utility for FAT and NTFS file systems. Data Recovery from damaged disks and partitions.
www.bitmart.net
 
Data Recovery Services - ActionFront - Critical Server Data Recovery
ISO certified data recovery services with labs in Atlanta, Santa Clara, Dallas, Chicago, Toronto (also Buffalo and Tokyo Japan)
www.actionfront.com
 
Hard Drive Data Recovery Software: Recover Deleted Files- Recover ...
Data recovery software for recovering files that have been deleted or lost due to the hard drive format, virus infection, unexpected system shutdown or ...
www.recovermyfiles.com
 
Data Recovery Group - Hard Drive Data Recovery Services
Data Recovery is Our Only Business! Data Recovery Group's a complete data recovery service that specializes in recovering data from hard disk drives.
www.datarecoverygroup.com
 
Data Recovery by CBL: Hard Drive Recovery Services
Worldwide Data Recovery Services at CBL. Specializing in data recovery, hard drive recovery, hard disk drive recovery and RAID data recovery.
www.cbltech.com
 
Data Recovery Software, File Repair Utilities, Hard Disk Recovery ...
Hard drive data recovery software to perform data recovery & recover deleted files from Novell, Linux, Unix, Mac, Windows & data recovery services for hard ...
www.nucleustechnologies.com
 
AT&DR: Data Recovery and Liabillity
Associated Technologies offers complete data recovery solutions with services for any type of data storage device, including the following: hard drives, ...
www.datarecovery.com
 
Ontrack UK - Data recovery services & recovery software - hard ...
Ontrack offers data recovery services & software for: hard drive recovery, file recovery, server recovery, email recovery, tape recovery, RAID recovery.
www.ontrack.co.uk
 
Beginners Guides: Hard Drive Data Recovery - PCSTATS.com
Beginners Guides: Hard Drive Data Recovery - PCSTATS.com.
www.pcstats.com
 
File Recovery and Data Recovery Software. Hard Drive recovery utility
Data recovery software for FAT, NTFS, Ext2FS file systems. File recovery after FDISK, MBR destruction, FAT damaged, virus infection. Dynamic disk support.
www.data-recovery-software.net
 
Data recovery - Wikipedia, the free encyclopedia
Data recovery is the process of salvaging data from damaged, failed, ... Although there is some confusion as to the term, data recovery can also be the ...
en.wikipedia.org
 
Active@ UNDELETE Data Recovery. Recover Deleted Files. Windows XP ...
Active@ UNDELETE - Data Recovery Software for all Windows File Systems. Recover deleted files from lost, damaged, formatted or reformatted partitions.
www.active-undelete.com
 
New Zealand Data Recovery & Computer Forensics Experts
New Zealand data recovery specialists & computer forensics investigation experts. Recovering lost data for businesses or legal evidence is all we do.
www.datarecovery.co.nz
 
Canada Data Recovery Services: Hard Disk Drive Recovery, Raid Data ...
Provides data recovery solutions for companies experiencing data loss from failed hard drives, raid arrays, and server systems.
www.datarecovery.ca
 
 

 
Content Menu
  • 10 easy steps to speed up your computer without upgrading

  • 10 proven tips to survive a computer crash

  • 7 critical steps to protect your data

  • add value by documenting your business

  • an introduction to tape backup

  • an outsourcers passage to india how to do it part i

  • are you prepared for a hard drive crash

  • asset searching for recovery actions the decision makers critical tool part 2

  • asset searching for recovery actions the decision makers most critical tool part 1

  • a beginner guide to web hosting

  • a customer complaint management system

  • a fresh start for family finances in 2005

  • background of password cracking

  • backing up your stuff part 2 a solution

  • before you take the plunge essential information on data recovery

  • booting problem in pc

  • business continuity and disaster recovery a business not a technology issue

  • business continuity and disaster recovery business impact analysis

  • business continuity and disaster recovery reducing your risk profile

  • business continuity and disaster recovery risk analysis and control

  • business continuity and disaster recovery selecting a business continuity strategy

  • business continuity and disaster recovery the business continuity and disaster recovery plan

  • business continuity testing starts with the risks

  • business needs vs network performance critical challenges facing network managers

  • can raid systems fail

  • career paths for a comptia a certified technician

  • career paths for comptia a certified technician

  • choosing a data recovery company

  • choosing data recovery company

  • common problems why hard disks crash

  • comparing data recovery software

  • compensating for disruptions in the oil and gas industry

  • computer data recovery options

  • computer disposal throwing away your computer money and idenity

  • computer viruses the basics

  • coping with a serious data loss from your computer hard drive

  • corporate information security is our information more secure since september 11th

  • datarecoverynet com enters medical industry

  • data backups are the biggest security threats

  • data backups are the biggest security threats surprised

  • data backups one key to business survival

  • data recovery

  • data recovery 1 on 1

  • data recovery and data loss a costly proposition

  • data recovery and data safety tips

  • data recovery beginners tips

  • data recovery for less

  • data recovery from laptops

  • data recovery made easy

  • data recovery software at your rescue

  • data recovery software comparison

  • data recovery the best method is prevention

  • data recovery the easy way

  • data recovery what not to do

  • data recovery what you need

  • data recovery you can get it back

  • data security are your assets secure

  • dealing with your pending pc disaster a guide for small business

  • did you ever want to completely erase everything on your computer

  • dirty little computer viruses and how to protect yourself

  • disaster planning ­v how important is it to you

  • disaster preparedness in a post 9 11 world

  • disaster recovery more than meets the eye

  • disc and data recovery

  • document management features for 2003

  • does it worth to backup emails from clients like outlook express

  • do it yourself data recovery freezer method

  • do i really need to backup

  • drive solutions inc expands data recovery service

  • easy file recovery basic backup guidelines

  • easy guide to raid recovery

  • eliminating the risk of delivering network ready applications

  • email recovery good software can fix your lost mail trouble

  • esecurity

  • exchange disaster recovery with sanrad v switch planning guide

  • e commerce a no nonsense perspective for new business

  • flash usb drive backup easily conveniently and securely

  • focusstor launches a new data backup recovery software

  • getting more bang for the storage buck

  • get down with ocp evaluating dba job applicants in an ocp world

  • got virus

  • got virus your data is not lost forever

  • great plains accounting support overview for it specialist

  • great plains dos support notes for consultant

  • great site ranking in google the secrets out

  • hackers given access to irs computers

  • hard disk data recovery expert choosing yours

  • hard dive failure what is a head crash

  • hard drive crash avoid making a bad situation worse

  • hard drive crash the essential data recovery report

  • health and medical advice on the internet use it wisely to overcome illness and find more happiness in your life

  • highlights of irs list of 2005 tax scam

  • highlights of irs list of 2005 tax scams

  • how multiple server hosting impacts your websites uptime

  • how multiple server hosting impacts your website s uptime

  • how multiple server hosting impacts your web sites uptime

  • how safe is your success part 5 of 8

  • how safe is your success part 6 of 8

  • how secure are online data backups

  • how to avoid everyday sales mistakes

  • how to backup a pc

  • how to backup windows xp home edition

  • how to backup your computer files

  • how to backup your hard drive

  • how to check the status of your tax refund online

  • how to fight cyberterrorism

  • how to prevent computer security risk and how to keep your small business safe

  • how why gps offers affordable fleet tracking

  • how you can avoid my data recovery nightmare

  • hr managers use computer forensics to investigate employee allegations

  • hurricanes wilma katrina and rita force businesses to rethink computer

  • identity theft and credit reports

  • identity theft recovery the road back

  • identity theft safeguarding cant hurt

  • identity theft the road back

  • improving sql performance

  • index

  • information security for smes

  • insure your information backup software

  • internet network security policies need a radical rethink

  • intranet

  • iscsi vs fc for meeting mission critical requirements

  • its all in the planning disaster recovery

  • it department skills to support microsoft great plains and microsoft crm

  • it in house support microsoft great plains and crm

  • keep a diary of your computer

  • learn how to safely backup your hard drive

  • lightning season how to avoid data loss

  • linux or windows which is it

  • loans for bad debtors discarding debt disorganization to recover financial growth

  • local vs remote data backup the pros and cons

  • mcse 70 290 certification primer

  • microsoft great plains customization recovery upgrade for large corporation

  • microsoft great plains customization upgrade recovery visual studio vb 6 0

  • microsoft r exchange server utilities eseutil isinteg

  • microsoft sql 2000 disaster recovery with sanrad v switch planning guide

  • mr

  • need a copy of your tax return information

  • new generation of financial information systems makes crunching numbers faster and easier

  • new iomega tera series desktop hard drive with 1tb capacity

  • nucleus kernel for fat and ntfs

  • nucleus kernel for fat data recovery software

  • nucleus kernel for fat ntfs data recovery software

  • nucleus kernel for ntfs data recovery softwares

  • online investing and trading discussions at www streetplayer com

  • openly sharing your rfp objectives and information with vendors

  • options for computer data recovery

  • outsourcing it asset retirement

  • outsourcing multiplying it services

  • paragon drive copy 8 0

  • planning for 2002 business recovery use public relations firepower

  • protecting your identity on the internet

  • protect yourself before your hard drive crashes

  • quick system restore with asr backups

  • raid disk recovery

  • ready for a business recovery

  • recognizing a pc with malware

  • recover deleted data easily

  • reduce tco the java database way

  • reinstall windows xp on your computer

  • rotator

  • scalability testing 7 steps towards success

  • scalability testing 7 tips for improvement

  • secure offsite backup services and software online file backup and storage remote online backup

  • secure your data windows data backup computer software

  • small business computer security the basics

  • small business network security 101

  • software that takes care of other software

  • sql administrator skills required to support microsoft great plains

  • syi save your identity

  • teosoft cleanspace 9 software

  • the best data recovery choice for you

  • the day my laptop was stolen almost killed my business

  • the devastation of data loss and what you can do about it

  • the essential data recovery report

  • the google patent reveals the secret to great site ranking

  • the importance of engaging a qualified data recovery expert

  • the importance of proper security for your pc

  • the mystery of the unknown

  • the seven deadly habits of a dba and how to cure them

  • the seven golden rules of data backups

  • the worst case scenario how to protect your data

  • think you have a dead hard drive

  • top 10 ways to protect yourself from computer viruses

  • top 10 ways to protect yourself from online identity theft

  • top 5 backup tools you can pick up for pennies

  • top 7 reasons you should back up your data online

  • top computer problems leading to data recovery

  • trouble shooting hard drive problems part 2

  • using sanrad v switch as the vss hardware provider for windows backups

  • using system restore to save yourself from formatting your hard drive

  • webfarms ii balancing the load

  • welcome to the world of knoppix

  • what could macedonia learn from a tiger the asian tigers and the phenomenon of uninterrupted economic growth

  • what is data recovery

  • what is data recovery a brief introduction

  • why usability is important to you

  • will you recover

  • working from home for yourself or someone else

  • your hard disk failed dont panic

  • your hard disk failed don t panic

  • your hard drive is going to explode why a ups is essential

  • your privacy exposed computer forensics international uncovers secrets about recycled hard drives

  • you can recover deleted data

  • you lost your data dont panic

  • you need to backup