Figure 1 Oracle database storage hierarchy without and with ASM
Why ASM over LVM?
As mentioned above, we require ASM disk group members in Serviceguard configurations to be raw logical volumes managed by LVM. We leverage existing
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The disadvantages of the
•Additional configuration and management tasks are imposed by the extra layer of volume management (administration of volume groups, logical volumes, physical volumes).
•There is a small performance impact from the extra layer of volume management.
Configuring LVM Volume Groups for ASM Disk Groups
We require ASM disk group members in Serviceguard configurations to be raw logical volumes managed by LVM. But these logical volumes presented to ASM should resemble raw disks, as far as possible. Hence, each LVM logical volume (LV) used as a member of an ASM disk group is required to be laid out to occupy the usable space, in contiguous fashion, of exactly one single physical volume (PV). This implies that the LV:
•should be contiguous,
•should not be striped or mirrored,
