Oracle官方倒是给出了各个版本集群ocr盘和vote盘最小值。一般给5G足够了

https://docs.oracle.com/en/database/oracle/oracle-database/19/cwlin/identifying-storage-requirements-for-oracle-automatic-storage-management.html#GUID-82B9A93B-185F-4DE8-8D90-606192004EAD

看看各个版本的手册
For Oracle Clusterware installations, you must also add additional disk space for the Oracle ASM metadata. You can use the following formula to calculate the disk space requirements (in MB) for OCR and voting files, and the Oracle ASM metadata:

total = [2 * ausize * disks] + [redundancy * (ausize * (all_client_instances + nodes + disks + 32) + (64 * nodes) + clients + 543)]
redundancy = Number of mirrors: external = 1, normal = 2, high = 3, flex = 3.

ausize = Metadata AU size in megabytes
all_client_instance = Sum of all database clients and ACFS proxy instances
nodes = Number of nodes in cluster.
clients - Number of database instances for each node.
disks - Number of disks in disk group.

我们 11g 最佳实践 3 块 1g OCR ,在 19 c 规划中 3 块 3 g OCR。