It's a simple explanation: the old way requires you to shut down servers in order to change the high availability configuration / topography. This is undesirable for a 24x7 operation situation - it's much better to be able to dynamically issue a SQL statement (from any client!) and have the server do 'the right thing' underneath the covers to reconfigure the mirror and copy nodes. Note that in SQL Anywhere 16, there are a number of enhancements to dynamically 'convert' high-availability and copy nodes without taking the database servers offline - see the SQL Anywhere 16.0 new features section in the documentation for more details. answered 31 Dec '13, 11:35 Jeff Albion 1
The other reasons that the new way was added were: 1) so that mirroring could also support read-only scale-out 2) so that the majority of the high availablitity/read-only scale-out configuration is stored in the database instead of spread over three or more command lines.
(02 Jan '14, 11:05)
Ian McHardy
|