Dual Loading of spatial data for update and fail-over using GO Loader.
Snowflake Software works with a number of customers where spatial data underpins key external and internal services. In the United Kingdom OS MasterMap data is a key spatial dataset with updates supplied every 6 weeks. However what happens when it is time to apply these updates to your live system or the unthinkable happens and there is a complete hard disk failure.
There are a number of different fail-over solutions however creating a "Dual Load" using GO Loader is simple solution that any organisations can consider.
It basically means creating two copies of the data in different users, tables and tablespaces within the same database. Ideally the tablespaces containing the tables would be setup to be physically on different hard disks within the server for I/O and failover reasons. A third user has database views onto one of the two sets of data tables and remains a static connection point for applications such as MapInfo and/or ArcSDE. These views can then be ‘swapped’ using simple scripts to make one data set or the other ‘live’. Updates and COU can then be applied to the ‘non-live’ dataset without disruption to your customers access.
Benefits of using a dual load:
1. Minimise downtime during COU load and provide 24x7 access.
2. Minimise disruption when disks etc fails
3. Allow changes and updates to made when access to the dataset is required.
Contact the Snowflake Support team if you need any help with setting up a Dual Load
(....before we receive your urgent phone call last thing on Friday afternoon after a database crash!)
Hopefully you've seen our GML quiz? It was really popular and great for beginners. If you haven't seen it, why not take a peek at this link and have a go?
