很早之前就有传闻Oracle12g（也许不是g）版本将不再支持裸设备。而这份声明在最新发布的Oracle11gR2中就已经有所体现。以下完全通过阅读文档而得，并非实践经验，各位自行取舍。

Block and Raw Devices Not Supported with OUI
With this release, OUI no longer supports installation of Oracle Clusterware files on
block or raw devices. Install Oracle Clusterware files either on Automatic Storage
Management diskgroups, or in a supported shared file system.

不再支持将文件存储在裸设备上，但是仅仅局限于使用OUI图形界面创建数据库，那么命令行方式应该还是可以的。

For new installations, OCR and voting disk files can be placed either on ASM, or on a
cluster file system or NFS system. Installing Oracle Clusterware files on raw or block
devices is no longer supported, unless an existing system is being upgraded.

Oracle Clusterwae需要的OCR和Voting disk可以存储在ASM或者集群文件系统或者NFS中，对于全新安装，裸设备不再被支持，但是如果是升级而来的话（比如从10g升级到11g），仍然支持。

Voting Disk Backup Procedure Change
In prior releases, backing up the voting disks using a dd command was a required
postinstallation task. With Oracle Clusterware release 11.2 and later, backing up and
restoring a voting disk using the dd command is not supported.
Backing up voting disks manually is no longer required, as voting disks are backed up
automatically in the OCR as part of any configuration change and voting disk data is
automatically restored to any added voting disks.

之前Voting disk因为是存储在裸设备中的，因此备份需要使用dd命令来手动执行，在11gR2中，通过dd备份Voting disk不再被支持，同时，也无需通过任何方法手动备份Voting disk了，备份将自动进行。