說明

視圖V$ASM_DISKGROUP和V$ASM_DISKGROUP_STAT字段和功能基本類似，但V$ASM_DISKGROUP展示的數據可能更多。
官方說明如下:

V$ASM_DISKGROUP_STAT displays performance statistics in the same way that V$ASM_DISKGROUP does, but without performing discovery of new disk groups. This results in a less expensive operation. However, since discovery is not performed, the output of this view does not include any data about disk groups that are new to the system.
The columns for V$ASM_DISKGROUP_STAT are the same as those for V$ASM_DISKGROUP.

大概意思如下：
V$ASM_DISKGROUP_STAT顯示性能統計數據的方式與V$ASM_DISKGROUP相同，但不執行發現新磁盤組的操作。這導致了一個較低的操作成本。然而，由於沒有執行發現，這個視圖的輸出不包括任何關於系統中新的磁盤組的數據。

字段展示

視圖V$ASM_DISKGROUP字段。

序號	字段名	注釋信息
1	GROUP_NUMBER	Cluster-wide number assigned to the disk group (primary key) 分配給磁盤組的集群范圍的號碼（主鍵）
2	NAME	Name of the disk group 磁盤組的名稱
3	SECTOR_SIZE	Physical block size (in bytes) 物理塊大小（以字節為單位）
4	BLOCK_SIZE	Oracle ASM metadata block size (in bytes) Oracle ASM元數據塊的大小（以字節為單位）
5	ALLOCATION_UNIT_SIZE	Size of the allocation unit (in bytes) 分配單元的大小（以字節為單位）
6	STATE	State of the disk group relative to the instance: CONNECTED - Disk group is in use by the database instance BROKEN - Database instance lost connectivity to the Oracle ASM instance that mounted the disk group UNKNOWN - Oracle ASM instance has never attempted to mount the disk group DISMOUNTED - Disk group was cleanly dismounted by the Oracle ASM instance following a successful mount MOUNTED - Instance is successfully serving the disk group to its database clients QUIESCING - CRSCTL utility attempted to dismount a disk group that contains the Oracle Cluster Registry (OCR). The disk group cannot be dismounted until Cluster Ready Services (CRS) exits, because the disk group contains the OCR.
7	TYPE	Redundancy type for the disk group: EXTERN NORMAL HIGH
8	TOTAL_MB	Total capacity of the disk group (in megabytes) 磁盤組的總容量（單位：以兆字節計）
9	FREE_MB	Unused capacity of the disk group (in megabytes) 磁盤組的未使用容量（單位：以兆字節計）
10	HOT_USED_MB	Number of used megabytes in the hot region 熱區中已使用的兆字節的數量
11	COLD_USED_MB	Number of used megabytes in the cold region 冷區使用的兆字節數
12	REQUIRED_MIRROR_FREE_MB	Amount of space that is required to be available in a given disk group in order to restore redundancy after one or more disk failures. The amount of space displayed in this column takes mirroring effects into account. 為了在一個或多個磁盤故障后恢復冗余，在一個給定的磁盤組中需要的可用空間量。這一欄顯示的空間量考慮到了鏡像效果。
13	USABLE_FILE_MB	Amount of free space that can be safely utilized taking mirroring into account and yet be able to restore redundancy after a disk failure 在考慮到鏡像的情況下，可以安全利用的自由空間的數量，但在磁盤故障后能夠恢復冗余。
14	OFFLINE_DISKS	Number of disks in the disk group that are currently offline 磁盤組中目前處於離線狀態的磁盤數量
15	COMPATIBILITY	Minimum software version required for an ASM instance to mount this disk group ASM實例掛載該磁盤組所需的最小軟件版本
16	DATABASE_COMPATIBILITY	Minimum software version required for a database instance to use files in this disk group 數據庫實例使用該磁盤組中的文件所需的最小軟件版本
17	VOTING_FILES	Indicates whether the disk contains voting files (Y) or not (N) 表示磁盤是否包含投票文件（Y）或不（N）

重要字段解釋

視圖V$ASM_DISKGROUP可主要關注GROUP_NUMBER、NAME、TOTAL_MB、FREE_MB、REQUIRED_MIRROR_FREE_MB、USABLE_FILE_MB，在此講解REQUIRED_MIRROR_FREE_MB、USABLE_FILE_MB兩個字段的計算方法，其他字段意思相對明顯，通過注釋可了解其作用。