Database Reference
In-Depth Information
Figure 2-3.
Comparing a typical logical volume manager with Oracle ASM
Very often you find discussions around ASM to be of a political nature. With the deployment of ASM the database
administrator enters the world of the storage or—depending on your company—the system administrator's realm.
Since they are most likely not aware of ASM or what it can do and how to use it, a lot of resistance will likely be faced.
The factor of job security also plays an important role in the discussions. You read before that ASM is implemented
as an Oracle instance which is radically different from the way the storage or operating system administrator worked
before. Instead of entering commands on the shell prompt the storage administrator will have to log in to the ASM
instance and perform the maintenance from there. The alternative way of administering ASM is by using Oracle
Enterprise Manager. Either way, the implementation of ASM resembles a paradigm shift. Beginning with Oracle 11.1
however it is possible to separate the administration of the storage and cluster layer to a dedicated account on the
operating system which is different from the oracle account. If needed the separation of duties that has worked so well
for Oracle 9i can be carried over into the cloud age.
Enhancements in the Cluster Layer
Oracle Clusterware and Automatic Storage Management together make up the cluster layer in Oracle RAC. It
includes the High Availability framework and the storage management. For quite a while now it has been possible
to run Oracle RAC without any third-party Clusterware at all. For those users, who probably form the majority of
Oracle's RAC customers the following sections are of interest: The limit of 63 ASM disk groups has been increased.
This could be potentially interesting for consolidated environments where for some reason each database has its
own disk group.
Oracle also allows you now to store the ASM password file in a shared ASM disk group. This new ability is not only
useful, but also a prerequisite for using Flex ASM.
Search WWH ::
Custom Search