Automatic Storage Management (ASM)

ASM provides a clustered file system with volume management for Oracle databases. Disk groups are limited by the performance of the slowest member and so it is recommended to place all protected virtual disks used in a disk group on storage with a similar I/O profile.

Oracle best practice dictates that two ASM disk groups should be created, one with a sequential I/O profile for log files, and one with a random I/O profile for data files. By selecting an Oracle database virtual machine for protection, Zerto automatically protects all virtual disks assigned to the virtual machine, and therefore all disk groups are included in the protection. As Zerto maintains write-order fidelity of all the disks within a virtual machine, and between virtual machines in the same VPG, protecting a virtual machine with multiple disk groups recovers all the disk groups to the exact same point-in-time. The journal never presents a checkpoint available for selection where the disk groups are at different points-in-time.

Zerto best practice: In a VMware vSphere environment, it is not recommend to use ASM failure groups. The Oracle Databases on VMware Best practices guide states:

"Do not use Oracle ASM failure groups. Oracle failure groups consume additional CPU cycles and can operate unpredictably after suffering a disk failure. When using external redundancy, disk failures are transparent to the database and consume no additional database CPU cycles, because this is offloaded to the storage processors."