Oracle ASM Storage Limits
Oracle ASM provides near unlimited capacity for future growth, but does have some storage limits. For example, Oracle ASM has the following limits on the number of disk groups, disks, and files:
63 disk groups in a storage system
10,000 Oracle ASM disks in a storage system
1 million files for each disk group
Without any Oracle Exadata Storage, Oracle ASM has these storage limits:
***2 terabytes (TB) maximum storage for each Oracle ASM disk***
20 petabytes (PB) maximum for the storage system
With all Oracle Exadata Storage, Oracle ASM has these storage limits:
4 PB maximum storage for each Oracle ASM disk
40 exabytes (EB) maximum for the storage system
The maximum size limit of a disk group equals the maximum disk size multiplied by the maximum number of disks in a disk group (10,000).
The maximum number of disks across all disk groups is 10,000. The 10,000 disks can be in one disk group or distributed across a maximum of 63 disk groups. This is a limitation on the number of Oracle ASM disks, not necessarily the number of spindles. A storage array could group multiple spindles into a LUN that is used as a single Oracle ASM disk. However Oracle ASM is currently limited to 2 TB in a single disk unless using Oracle Exadata storage.原文：http://blog.51cto.com/roidba/2157663