User mode : 300MB(excepting for optional products.)

When the synchronization mode is used:
1MB + (number of request queues x I/O size) +
(2MB + Difference Bitmap Size x number of mirror disk resources and
hybrid disk resources)

When the asynchronous mode is used:
1MB + (number of request queues x I/O size)
+ (3MB
+ (number of asynchronous queues x I/O size)
+ (I/O size / 4KB x 8B + 0.5KB) x (max size of history file / I/O size +
number of asynchronous queues)
+ (Difference Bitmap Size)
) x number of mirror disk resources and hybrid disk resources

When the kernel mode LAN heartbeat driver is used:
8MB

When the keepalive driver is used:
8MB

(*) Estimated I/O size is as follows:
     - 6MiB (RHEL9)
     - 1MiB (RHEL8)
     - 124KiB (RHEL7)
(*) For the setting value of the number of request queues and asynchronization queues, see "Understanding Mirror disk resources" of "Group resource details" in the "Reference Guide".
(*) For the required size of a partition for a disk heartbeat resource, see "Shared disk".
(*) For the required size of a cluster partition, see "Mirror disk" and "Hybrid disk".

Right after installation : 300MB
During operation : 5.0GB + 1.0GB(A disk capacity required to use mirror disk resources and hybrid disk resources.)