In this article I describe how we created a redundant PostgreSQL database on the Amazon cloud using EBS snapshots as backups to deploy a PostgreSQL DB server DR mobile application for one of our customers.
PostgreSQL 9.1 includes new capabilities for asynchronous fast replication syncing between master and slaves. The master server streams new data to the current available slave. This version includes great improvements that generated significant fast WAL (Write Ahead Log) processing, which generates replication and fast launching capabilities for the slave servers.
It is surprising to see that a significant amount of AWS users are aware of the benefits of ELB, yet not familiar with the inherent opportunity to increase availability by using ELB across multiple availability zones. By not doing so, should an outage or a drop in an AWS availability zone service level, the benefit of the ELB is nearly lost. Setting up ELB across multiple availability zones is a relatively straightforward effort that can easily be done if brought to the attention of the user at the time of the ELB configuration.
Cloud providers consolidate access to many consumers’ data, or should we say victims’ data into a single point of (hacking) entry. Recently, the major popular clouds have increasingly become the focus of attacks by hackers. IT organizations may think that their legal liability can be outsourced, but total misconception. The contract with the IaaS vendors includes security obligations, however it does not negat the liability of the software vendor as the responsibe party. So rather than focusing on contracts and limiting liability in cloud services deals, the SaaS vendor must focus on controls and audit-ability.
Traditionally delivering high availability often meant replicating everything. However, today with the option of going to the cloud we can say that providing two of everything is costly. High availability should be planned and achieved at several different levels: including the software, the data center and the geographic redundancy.