HP Serviceguard Extension for RAC (SGeRAC) manual Serviceguard Extension for RAC Toolkit operation

An example of a bottleneck created if we only have a package for Oracle Clusterware is this: if we concentrate all storage management in the Oracle Clusterware package, then any time there is a change in the storage configuration for one database (for example, an SLVM volume group is added), we would have to modify the Oracle Clusterware package.

These are the main arguments in favor of having separate packages for Oracle Clusterware and each RAC database. But then the question arises: how do we ensure that these packages start and halt in the proper order? Prior to version A.11.17, SG/SGeRAC did not provide a mechanism for package ordering.

Two new features are introduced in SG/SGeRAC that help us solve this problem: MNPs and simple package dependencies. The combination of MNPs and simple package dependencies is a very good fit for our problem of coordinating Oracle RAC and SGeRAC. We configure Oracle Clusterware as one MNP and each RAC database as another MNP and we set up the database MNPs to depend on the Oracle Clusterware MNP. This is the core concept of SGeRAC.

Both Oracle Clusterware and the RAC database are multi-instance applications well suited to being configured as MNPs. Further, the use of MNPs reduces the total package count and simplifies SGeRAC package configuration and administration. Simple package dependencies enable us to enforce the correct start/stop order between the Oracle Clusterware MNP and RAC database MNPs.

Serviceguard Extension for RAC Toolkit operation

In this section, we first discuss how SGeRAC organizes the flow of control through the combined stack. Then we deal with the interactions of the toolkit, first with Oracle RAC, and then with the storage management subsystems.

Figure 15 shows how the toolkit enables SGeRAC and Oracle Clusterware to work in harmony and ensure proper sequencing between themselves and the resources they manage.

It shows Oracle Clusterware and the resources it manages, via its Cluster Ready Services (CRS) component, in red and the SGeRAC package manager (PM) in blue, as well as the resources it manages.

Each resource manager starts up and shuts down the resources it manages, honoring the dependencies that it recognizes. The dependencies are shown in red or blue depending on whether they are Oracle Clusterware dependencies or SGeRAC dependencies.

The storage packages (Oracle Clusterware Storage and Database Storage) and associated dependencies only exist for CFS, and the ASM instance and associated dependencies only exist when ASM is being used.

SGeRAC provides scripts for Oracle Clusterware MNP, ASMDG MNP, and RAC DB instance MNP. The Oracle Clusterware MNP starts, stops, and checks the status of the Oracle Clusterware. The ASMDG MNP mounts dismounts and monitors the status of ASM Disk groups. The RAC DB instance MNP starts, stops, and checks the status of the RAC instance. Oracle Clusterware and RAC instance auto-start have to be disabled (using Oracle specified commands and procedures, as previously discussed in this chapter).

84 SGeRAC Toolkit for Oracle RAC 10g or later