Is it possible to use ASM for the OCR and voting disk?
Yes. As of Oracle Real Application Clusters 11g Release 2, the OCR and Voting Disks can be stored in ASM. This is the recommended best practice for this release. For releases prior to 11g Release 2, the OCR and voting disk must be on RAW devices or CFS (cluster filesystem). RAW devices (or block devices on Linux) is the best practice for Oracle RAC 10g or Oracle RAC 11g Release 1.