V$ASM_DISK

In an Automatic Storage Management instance, V$ASM_DISK displays one row for every disk discovered by the Automatic Storage Management instance, including disks which are not part of any disk group. In a database instance, V$ASM_DISK only displays rows for disks in disk groups in use by the database instance.

Column	Datatype	Description
`GROUP_NUMBER`	`NUMBER`	Number of the disk group containing the disk (foreign key to the `V$ASM_DISKGROUP` view)
`DISK_NUMBER`	`NUMBER`	Number assigned to the disk within its disk group
`COMPOUND_INDEX`	`NUMBER`	A 32-bit number consisting of a disk group number in the high-order 8 bits and a disk number in the low-order 24 bits (for efficient access to the view)
`INCARNATION`	`NUMBER`	Incarnation number for the disk
`MOUNT_STATUS`	`VARCHAR2(7)`	Per-instance status of the disk relative to group mounts: `MISSING` - Automatic Storage Management metadata indicates that the disk is known to be part of the Automatic Storage Management disk group but no disk in the storage system was found with the indicated name `CLOSED` - Disk is present in the storage system but is not being accessed by Automatic Storage Management `OPENED` - Disk is present in the storage system and is being accessed by Automatic Storage Management. This is the normal state for disks in a database instance which are part of a Disk Group being actively used by the instance. `CACHED` - Disk is present in the storage system and is part of a disk group being accessed by the Automatic Storage Management instance. This is the normal state for disks in an Automatic Storage Management instance which are part of a mounted disk group. `IGNORED` - Disk is present in the system but is ignored by ASM because of one of the following: The disk is detected by the system library but is ignored because an ASM library discovered the same disk ASM has determined that the membership claimed by the disk header is no longer valid `CLOSING` - ASM is in the process of closing this disk
`HEADER_STATUS`	`VARCHAR2(12)`	Per-instance status of the disk as seen by discovery: `UNKNOWN` - Automatic Storage Management disk header has not been read `CANDIDATE` - Disk is not part of a disk group and may be added to a disk group with the `ALTER DISKGROUP` statement `INCOMPATIBLE` - Version number in the disk header is not compatible with the Automatic Storage Management software version `PROVISIONED` - Disk is not part of a disk group and may be added to a disk group with the `ALTER DISKGROUP` statement. The `PROVISIONED` header status is different from the `CANDIDATE` header status in that `PROVISIONED` implies that an additional platform-specific action has been taken by an administrator to make the disk available for Automatic Storage Management. `MEMBER` - Disk is a member of an existing disk group. No attempt should be made to add the disk to a different disk group. The `ALTER DISKGROUP` statement will reject such an addition unless overridden with the `FORCE` option. `FORMER` - Disk was once part of a disk group but has been dropped cleanly from the group. It may be added to a new disk group with the `ALTER DISKGROUP` statement. `CONFLICT` - Automatic Storage Management disk was not mounted due to a conflict `FOREIGN` - Disk contains data created by an Oracle product other than ASM. This includes datafiles, logfiles, and OCR disks.
`MODE_STATUS`	`VARCHAR2(7)`	Global status about which kinds of I/O requests are allowed to the disk: `UNKNOWN` - Automatic Storage Management disk mode is not known (typically the disk is not mounted) `ONLINE` - Disk is online and operating normally. Reads and writes are attempted. `OFFLINE` - Disk is offline and access to data is not permitted. Reads and writes are not attempted. An offline disk remains logically part of its disk group.
`STATE`	`VARCHAR2(8)`	Global state of the disk with respect to the disk group: `UNKNOWN` - Automatic Storage Management disk state is not known (typically the disk is not mounted) `NORMAL` - Disk is online and operating normally `ADDING` - Disk is being added to a disk group, and is pending validation by all instances that have the disk group mounted `DROPPING` - Disk has been manually taken offline and space allocation or data access for the disk halts. Rebalancing will commence to relocate data off the disks to other disks in the disk group. Upon completion of the rebalance, the disk is expelled from the group. `HUNG` - Disk drop operation cannot continue because there is insufficient space to relocate the data from the disk being dropped `FORCING` - Disk is being removed from the disk group without attempting to offload its data. The data will be recovered from redundant copies, where possible. `DROPPED` - Disk has been fully expelled from the disk group
`REDUNDANCY`	`VARCHAR2(7)`	Hardware redundancy of the disk: `UNKNOWN` `UNPROT` `MIRROR` `PARITY` Note: This column is valid only if an ASMLIB is present that supports returning hardware redundancy information. This column is not related to the redundancy of the disk group of which the disk is a member.
`LIBRARY`	`VARCHAR2(64)`	Name of the library that discovered the disk
`OS_MB`	`NUMBER`	Size of the disk (in megabytes) as reported by the host operating system
`TOTAL_MB`	`NUMBER`	Total capacity of the disk (in megabytes)
`FREE_MB`	`NUMBER`	Unused capacity of the disk (in megabytes)
`NAME`	`VARCHAR2(30)`	Name of the disk
`FAILGROUP`	`VARCHAR2(30)`	Name of the failure group containing the disk
`LABEL`	`VARCHAR2(31)`	Disk label portion of the name returned by discovery
`PATH`	`VARCHAR2(256)`	Operating system pathname portion of the name returned by discovery
`UDID`	`VARCHAR2(64)`	Unique Device ID portion of the name returned by discovery
`PRODUCT`	`VARCHAR2(32)`	Name of the manufacturer and the name of the product. All disks with the same product id will have the same performance and reliability characteristics.
`CREATE_DATE`	`DATE`	Date and time when the disk was added to the disk group
`MOUNT_DATE`	`DATE`	Date and time when the disk was mounted by the first instance
`REPAIR_TIMER`	`NUMBER`	Seconds remaining until the disk is automatically dropped (`0` if not failed)
`READS`	`NUMBER`	Total number of I/O read requests for the disk
`WRITES`	`NUMBER`	Total number of I/O write requests for the disk
`READ_ERRS`	`NUMBER`	Total number of failed I/O read requests for the disk
`WRITE_ERRS`	`NUMBER`	Total number of failed I/O write requests for the disk
`READ_TIME`	`NUMBER`	Total I/O time (in hundredths of a second) for read requests for the disk if the `TIMED_STATISTICS` initialization parameter is set to `true` (`0` if set to `false`)
`WRITE_TIME`	`NUMBER`	Total I/O time (in hundredths of a second) for write requests for the disk if the `TIMED_STATISTICS` initialization parameter is set to `true` (`0` if set to `false`)
`BYTES_READ`	`NUMBER`	Total number of bytes read from the disk
`BYTES_WRITTEN`	`NUMBER`	Total number of bytes written to the disk
`PREFERRED_READ`	`VARCHAR2(1)`	Status of the preferred read failure group: `U` - Disk group has no preferred read failure group `Y` - Disk is a preferred read disk `N` - Disk is not a preferred read disk For a disk group with one or more preferred read failure groups, if the disk is in one of the preferred read failure groups, the value of this column is `Y`; otherwise it is `N`.

Note:

The GROUP_NUMBER and DISK_NUMBER columns will only be valid if the disk is part of a disk group which is currently mounted by the instance. Otherwise, GROUP_NUMBER will be 0, and DISK_NUMBER will be a unique value with respect to the other disks that also have a group number of 0.