This issue is applicable to Veritas Operations Manager HSCL Pack 1 Add-on for Management Server.
This issue is observed when an Oracle ASM disk group is dismounted on a RAC node. Management Server console displays total and allocated capacities as zero until the discovery on any other node with the ASM disk group happens. This issue is not applicable to standalone ASM discovery.
Using Management Server console, refresh any other node, which is part of the RAC configuration, and has the disk group in the mounted state.