This blog was originally started to better help me understand the technologies in the CCIE R&S blueprint; after completing the R&S track I have decided to transition the blog into a technology blog.
CCIE #29033

This blog will continue to include questions, troubleshooting scenarios, and references to existing and new technologies but will grow to include a variety of different platforms and technologies. Currently I have created over 185 questions/answers in regards to the CCIE R&S track!! Note: answers are in the comment field or within "Read More" section.

You can also follow me on twitter @FE80CC1E

Sunday, September 11, 2011

Availabilty

I have heard some engineers and administrators claim that their systems are available 100% of the time. I wanted to ensure that there is a clear understanding on what 100% availability means. Up-time does not equal availability; you can have a system that is up but the services may not be available. You also need to consider maintenance windows as this impacts your overall availability. If you do not have the ability to do maintenance without  impacting the services that you are providing then your overall availability percentages take a hit. Other things that may impact your ability of achieving 100% availability includes environmental's such as power, cooling, etc and other services that are required to provide access to the very services that you are providing such as internet connectivity, WAN, LAN, SAN, etc....

Below is a chart showing the availability percentages and the expected downtime per year based on these percentages.
 
So.....are you really providing 100% availability?

Saturday, September 10, 2011

vSphere 5.0 High Availability vs Previous Versions of VMware


This post is a follow up to a previous post "Virtualization-Vmware-Clusters and Blade Servers" where we discussed limitations with HA in previous versions of VMware.

In vSphere 5.0 the concept of 5 primary/secondary hosts has been eliminated and the concept of master/slave exists. A single host is the master and all other hosts are slaves, if the master fails then an election process is kicked off and a new master is elected.

This eliminates issues in previous versions of VMware where the primary/secondary concept existed and we needed to consider

  • Number of hosts in a cluster
  • Managing the role of the host
  • Number of consecutive host failures
  • Placement of hosts across blade chassis and stretched clusters
  • Partition scenarios likely to occur in stretched cluster environment

By the way Dave thanks for the link

Monday, September 5, 2011

You Never Know When You Need......

Cisco Borderless Network Architecture

Cisco's borderless networks provides secure, seamless, and reliable connectivity to anyone, anywhere, anytime to anything. Borderless network architecture is a technical architecture that allows organizations to realize these benefits.