Wednesday, September 2, 2015

History of Automation

Today I just came across this article thanks to Ruan for sharing such a nice piece of information. It has a correlation with release automation.

Noon Gun
The Noon Gun has been a historic time signal in Cape Town, South Africa since 1806. The gun is situated on Signal Hill, close to the center of the city.


Source: Wikipedia

And the first ever bug in the process was not a bug it was spider


After the advent of the galvanic telegraph, it became possible to trigger a gun remotely and since 1864 the Noon Gun has been fired from the master clock of the oldest timekeeper in the country, the South African Astronomical Observatory. One day in June 1895 the gun fired at 10:30 rather than 12:00 when a spider interfered with the relay used to remotely fire the gun

Thursday, March 19, 2015

Things to Remember during SQL SERVER HA Configuration

Recently configured a SQL SERVER high availability Cluster in AWS. the process was smooth and i followed a provided documentation however things to remember when configure HA in AWS

  1. Make sure your Cluster Quorum is on a separate host within different security zone just to ensure you fail-overs are remain intact in case of node failure.
  2. Each HA cluster need entries in primary DNS server to ensure parallel requests are processed however normal TTL time is 300 which means secondary server will not be available till 5 minutes of the last fail-over this situation can create real confusion during testing and configurations. so keep that minimum
  3. make sure your nodes are joined with this will help to use single user and permission level across all machines.
  4. the stuff i forgot during deployment was the binding of multiple IP address to the private network subnet. if the setting is not there listener will unable to communicate from the network locations.
  5. make sure your port 1433 is open from all security zone and port 137 and 139 are open from quorum witness.
  6. Opens the TCP ports 1433, 1434, 4022, 5022, and 135 on the Windows Firewall
  7. for cluster node need to ensure that static IP option is selected by default its dynamic. in case of dynamic IPs your cluster will remain offline.
  8. Ensure required Database is uses Full Recover model.
    1. SELECT name, recovery_model_desc  FROM sys.databases
  9.  Check DNS to ensure all availability group Listeners (e.g., AG1-Listener) IP addresses are listed.