Calculating ACTUAL and USED space in ASM Disk Group with NORMAL redundancy

Hi

Hello everyone

We are trying to calculate the actual available and used space for one of our ASM DISK GROUP DATA in our 19c database

The Disk Group has NORMAL redundancy

ASMCMD> lsdg - DATA

State  Type  Rebal Sector Logical_Sector Block    AU Total_MB  Free_MB Req_mir_free_MB Usable_file_MB Offline_disks Voting_files Name

MOUNTED NORMAL N     512       512  4096 4194304 10684160 10664828     2136832     4263998       0       Y DATA

There are 5 physical disk appx 2 TB that this (+DATA) disk group is made up of and since this is normal redundancy we would need one disk or 2 TB for mirroring / redundancy purpose( as reflected in the required_mirror_free_mb column of v$asm_diskgroup). That means the total available space in the disk group would be 8 TB Divided by 2 (to incorporate mirroring) = appx 4 TB and same is reflected in the USABLE_FILE_MB column of v$asm_diskgroup