Oracle ASM Storage Limits

在11g ASM中创建磁盘组时，如果LUN大小超过2T时，将会遇到ORA-15018, ORA-15099等错误。从12.1开始，compitable.asm和compitable.rdbms设置为12.1或者更高，可以创建使用单个超过2T的LUN，单盘最大限制是4PB起。下面是来自Oracle官方文档关于Oracle ASM Storage的限制信息。

Oracle ASM Storage Limits

Oracle ASM provides near unlimited capacity for future growth, but does have some storage limits.

Oracle ASM has the following limits on the number of disk groups, disks, and files:

• 511 disk groups in a storage system for Oracle Database 12c Release 1 or later

• 10,000 Oracle ASM disks in a storage system

• 1 million files for each disk group

Without any Oracle Exadata Storage, Oracle ASM has the following storage limits if theCOMPATIBLE.ASMorCOMPATIBLE.RDBMSdisk group attribute is set to less than12.1:

• 2 terabytes (TB) maximum storage for each Oracle ASM disk

• 20 petabytes (PB) maximum for the storage system

Without any Oracle Exadata Storage, Oracle ASM has the following storage limits if theCOMPATIBLE.ASMandCOMPATIBLE.RDBMSdisk group attributes are set to12.1or greater:

• 4 PB maximum storage for each Oracle ASM disk with the allocation unit (AU) size equal to 1 MB

• 8 PB maximum storage for each Oracle ASM disk with the AU size equal to 2 MB

• 16 PB maximum storage for each Oracle ASM disk with the AU size equal to 4 MB

• 32 PB maximum storage for each Oracle ASM disk with the AU size equal to 8 MB

• 320 exabytes (EB) maximum for the storage system

With all Oracle Exadata Storage, Oracle ASM has the following storage limits:

• 4 PB maximum storage for each Oracle ASM disk with the AU size equal to 1 MB

• 8 PB maximum storage for each Oracle ASM disk with the AU size equal to 2 MB

• 16 PB maximum storage for each Oracle ASM disk with the AU size equal to 4 MB

• 32 PB maximum storage for each Oracle ASM disk with the AU size equal to 8 MB

• 320 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 511 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.

File size limits are dependent on the value of the disk group compatibility attributes. Oracle ASM supports file sizes greater than 128 TB in any redundancy mode when the COMPATIBLE.RDBMS disk group attribute is set greater than10.1.

If COMPATIBLE.RDBMS is set to10.1, the file size limits are less. For example, with COMPATIBLE.RDBMS equal to10.1and the AU size equal to 1 MB, Oracle ASM file size limits are:

• External redundancy: 16 TB

• Normal redundancy: 5.8 TB

• High redundancy: 3.9 TB