Oracle ASM supports fixed partnership for Oracle ASM disks. Oracle ASM performs splitting and mirroring of data across all disk partners. Oracle ASM supports either four or eight disk partners for Oracle Database Appliance high-availability. Oracle Database Appliance X6-2 and X5-2 support four disks partnership.
Oracle Database Appliance X7-2 and later models have an eight disk partnership, if there are a minimum of eight disks. If there are not enough disks, then each disk partners with all others. For example, Oracle Database Appliance X8-2 with six SSDs does not have eight disks to maintain eight disks partnership, hence all six disks partner among themselves.
For two JBOD systems, disk partnerships are across the JBOD boundary. It means that any disk in the first JBOD partners with eight disks from second JBOD and vice versa.
Disk partnership information is a part of the asmappl.config file.
The disk partnership on Oracle Database Appliance high-availability system is as follows:
DATA Disk S0 partners with S1, S2, S3, S4, S11, S12, S13, S14
RECO Disk S0 partners with S4, S5, S6, S7, S8, S9, S10, S11
If disk in slot 0 is lost for any reason, then Oracle ASM restores and rebalances data on lost disks among the partners of the lost disk.
If disk in slot 0 is lost for any reason, Oracle ASM restores and rebalances data on lost disks among the partners of lost disk.