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High Availability Website Architecture

High Availability Website Architecture. www.inflow.com. 877-2INFLOW. Introduction Example ASP implementations Why build redundancy? Site components Proof of concept phase Adding redundancy layer-by-layer Typical Endpoint Global Site Load Balancing (GSLB). Agenda. Who is Inflow?

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High Availability Website Architecture

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  1. High Availability Website Architecture www.inflow.com 877-2INFLOW

  2. Introduction Example ASP implementations Why build redundancy? Site components Proof of concept phase Adding redundancy layer-by-layer Typical Endpoint Global Site Load Balancing (GSLB) Agenda

  3. Who is Inflow? Inflow is a leading provider of carrier-neutral datacenter and outsourced IT services 13 datacenter locations across the U.S ISO9001:2000 Certified Services: Colocation and Application Hosting Business Continuity/Disaster Recovery IT Consulting Introduction

  4. Sample Customers has divested its has acquired the has divested Its Speech Solutions Business to Application Hosting Business Continuity Customer Application Hosting Business Continuity Customer has been acquired by Enterprise Data Center Mgt Customer Application Hosting Customer Application Hosting Customer Nashville IDC Philadelphia IDC Denver IDC Denver IDC San Diego, Phoenix IDCs Confidential $34,500,000 September 2001 July 2002 Application Hosting Business Continuity Customer Application Hosting Customer Enterprise Data Center Mgt Customer Business Continuity Customer Application Hosting Customer Portland IDC Minneapolis IDC Denver IDC Phoenix IDC Austin IDC Application Hosting Customer Minneapolis IDC

  5. Local Customers

  6. Logistics ASP Schedules and tracks shipments Rating estimates Load and route optimization Construction Project Management ASP Scheduling, planning, status and reporting Maintenance ASP Tracks costs, PM events Reporting Alerting Example ASP implementations

  7. Clinical disasters are more frequent than catastrophic disasters Examples: User headspace error Fat finger of death Hardware (hard disk drive) failure Plumbing issue above server room Power issues Network outages Why build redundancy?

  8. Utility Services Network equipment Database layer Application layer Web layer Components

  9. Internet Service Provider(s) who provide “ping” Power Internal redundancy via generator and UPS Competitive Local Exchange Carriers (CLECs) who provide “pipes” Component - Utility Services

  10. Phase synching generators is expensive and complex Use a split block approach – redundant engines powering a single generator UPS provides power for 5-10 seconds while generator comes online Manage phases Evenly load phases – use ampmeter to meter Breakers should trip at 80% of rating Manage sustained load on redundant power supplies at <40% of rating Power Redundancy

  11. Routers (including CSU/DSUs) Border Gateway Protocol 4 (BGP4) is the standard edge routing protocol Cisco routers use Hot Spare Router Protocol (HSRP) Other vendors use Virtual Router Redundancy Protocol (VRRP) Firewall(s) Plan to add redundancy during your early stages See www.icsalab.net for a list of lab reports on firewalls Switches Multiple VLANs on redundant Switches can be trunked together on a single port (or set of ports) using IEEE802.1q or ISL (Cisco-proprietary) trunking Network Interface Cards NICs can be “teamed” for redundancy Component - Network equipment

  12. Storage intensive Most difficult and expensive to: Make redundant Backup Modify, upgrade and/or change Examples: IBM DB2 Oracle MySQL PostgreSQL Component - Database layer

  13. Processes business logic Assembles data for publication to weblayer Examples: ATG Dynamo BEA Weblogic IBM Websphere (Network Deploy) Component - Application layer

  14. Component - Web Layer • Publication engine • Examples: • Apache • Netscape Enterprise Server • IBM HTTP Server • Sun IPlanet

  15. Proof of Concept Phase

  16. Proof of Concept Phase • Typically “garage built” • Redundancy isn’t key • Getting the site working, tuned out and ready to launch is key • Typically not acceptable for bet-the-bank applications

  17. Network Redundancy

  18. Network Redundancy • Multiple ISPs • Use Border Gateway Protocol 4 (BGP4) for route determination • Multiple CLECs • Difficult to get Type I (eg: not resold Verizon) circuits • Difficult to get onto redundant SONET rings • Multiple routers • Redundant switching

  19. Web Layer Redundancy

  20. Web Layer Redundancy • Easiest layer to make redundant • Horizontally scalable • Usually start making all components redundant • Firewall • Layer 2 Switching • Local Server Load Balancers (LSLB)

  21. LSLB Terms and Concepts • Virtual Router Redundancy Protocol (VRRP) • Virtual IP Address (VIP) – What the world sees • Real IP Address (RIP) – Each of the load balanced servers • Least Connections – Ability of LSLB to dish out sessions to the RIP with least number of active connections • Stickiness or Persistance – Sticking a client to the same Webserver through the entire session • SSL Acceleration • LSLB does constant health checks of servers and will automatically pass new connections to survivors • LSLB strips the requesting client IP and replaces it with its own IP when sending to the Webserver.

  22. Challenges to Persistance • Meta Proxy Servers that frequently change source IP • AOL • MSN • LSLB can’t read a cookie in an encrypted payload of an SSL packet • Short SSL Session ID Timer (IE 5+)

  23. SSL Acceleration • Add-on feature • Saves labor by not having to admin so many Webservers, certificates, etc • Cures Stickiness/Persistance issues by decrypting the payload and allowing use of cookies that the LSLB can read • Client sends https request to VIP • LSLB passes to Accelerator • Accelerator decrypts and passes back to LSLB in http • LSLB reads payload (cookie) and passes to appropriate RIP • RIP responses to request through LSLB • LSLB passes to Accelerator for encryption • Accelerator encrypts and passes back to LSLB in https • LSLB responds to requesting client in https

  24. Application Layer Redundancy

  25. Application Layer Redundancy • Usually accomplished through software • Have to buy additional licensing • Might also be accomplished through LSLB • App servers can become RIPs • Webservers are the clients • Choose carefully • Is the app server J2EE compliant? (May not be very portable) • How is it licensed? (Could get expensive later) • Does it provide session state to the webservers? (Session state could make LSLB easier)

  26. Database Layer Redundancy

  27. Database Layer Redundancy • Requires OS support • Red Hat Cluster Suite on Enterprise Linux AS or ES • Veritas Cluster Server on RH Enterprise Linux AS or ES • MS Cluster Services – part of Enterprise Server 2003 • Shared Storage • Shared LUN for the Quorum • LUN for data • Direct Attached SCSI limits to two (2) nodes • Fiber Channel SAN allows more nodes depending on implementation • Hint: Get a FC fabric • Hint: make a dual path to take advantage of both SPs • Heartbeat between servers – hint: make redundant

  28. Typical endpoint

  29. Global Site Load Balancing (GSLB) • Can be done on LSLB hardware • Content Distribution Network (CDN) Providers are a better solution • Akamai • Speedera • CNAME your site to CDN provider • Can weight traffic between sites • Latency due to physical factors (eg: speed of light) dictates that synchronous hot sites be within 60 miles of each other

  30. Reference Sites • BEA Supported Platforms: http://edocs.bea.com/platform/docs81/support/supp_plat.html • ATG Supported Platforms: http://www.atg.com/en/products/requirements/atg_62.jhtml • IBM Websphere Supported Platforms: http://www-106.ibm.com/developerworks/websphere/downloads/WASsupport.html • IBM Websphere Application Server Network Deployment http://www-306.ibm.com/software/webservers/appserv/was/network/ • IBM DB2: http://www14.software.ibm.com/webapp/download/search.jsp?rs=db2pde • IBM HTTP Server: http://www-306.ibm.com/software/webservers/httpservers/ • Red Hat Cluster Suite: http://www.redhat.com/software/rha/cluster/ • Red Hat Enterprise Linux: http://www.redhat.com/software/rhel/ • Sun Java System Web Server: http://wwws.sun.com/software/products/web_srvr/datasheet.html • Alteon Websystems: http://www.nortelnetworks.com/products/01/alteon/index.html • Veritas Cluster Server: http://www.veritas.com/Products/www?c=product&refId=20 • Oracle on Linux: http://www.oracle.com/technologies/linux/ • Netscape Enterprise Servers: http://enterprise.netscape.com/ • eWeek article on MySQL Clustering http://www.eweek.com/article2/0,1759,1565415,00.asp

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