Overprovisioned Disk Space in ASM

Dec 18, 2025 8:52AM

Hi Team,

We have DBCS DB system with 1CDB with 1PDB in OCI
version 19.28
ASM single node

Unfortunately, We have provisioned DB instance with 8 TB storage but the actual we need is 1TB.

Space is wasted in this case, you can see each disk usage in below output. We want to reduce the size to 1TB from 8TB.

SQL> show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

    2 PDB$SEED                       READ ONLY  NO

    3 PRODDB1                        READ WRITE NO

SQL> alter session set container=PRODDB1;

Session altered.

NAME STATE TYPE SIZE_GB AVAILABLE_GB USED%

DATA CONNECTED EXTERN 8192 7909.79 3.44
RECO CONNECTED EXTERN 2048 2022.33 1.25

Disk Group Disk Name SIZE_GB AVAILABLE_GB USED%

Database - RAC/Scalability (MOSC)