In my previous article High Availability and SLA requirements for Oracle database we discussed that the successful High Availability (HA) begins with the understanding of Service Level Agreements (SLA) required by the business along with each of these dimensions. This guides important decisions on IT technology and determines the appropriate level of investment in HA architecture. Choosing the right technical solution for database system design from scratch is difficult. You can follow some best practices in building High Available Oracle database systems based on Availability Levels that match database industry standards. In this article I’ll share some best practices and my experience in architecting database systems for first 2,5 Availability Levels describing some technical solutions based on SAN, cluster, Clusterware, Oracle ASM, Cold Failover Cluster (CFC).
I’ll start with a graph below that illustrates Availability Continuum and depicts the increases in availability that can be gained with the progression between levels of availability. It is not based on empirical data, and the percentage values used are for illustrative purposes only, but being close (based on my experience) to real figures in common IT infrastructure for Oracle database environments though.
Another way to interpret the y-axis scale is as a measure of acceptable down time – the lower end of the axis represents a reasonable amount of down time as tolerable, whereas the upper end of the axis represents even the smallest amount of down time as being intolerable.
I see a lot of questions on shared file systems that can be used when people move from single instance to Oracle RAC database and Grid Infrastructure. The most common question is the following: “Should I place archive logs in OCFS2 or ASM or ACFS of 11g?” I’ll try to clarify this topic below.
First we need to understand a separation between Oracle database files and non-database files. Read more »
I sense the confusion between Oracle users running Oracle Grid Infrastructure 11gR2 with Automatic Storage Management (ASM) and Automatic Storage Management Cluster File System (ACFS) about the new license policy from Oracle. Oracle introduced a new all in one license called Cloud File System. Since this new Oracle licensing policy is not so straight forward, I’ll try to put some light on the topic. But first let’s see what Oracle Cloud File System itself is. Read more »
Oracle GRID Infrastructure 11gR2 introduces many great ASM features. However most of them are disabled by default even if you run Oracle 11gR2 database on it. Below I share some clarify on how to enable new ASM 11g features for your 11g database. Read more »