Oracle ACFS Command-Line Tools for Snapshots

This topic provides a summary of commands to manage Oracle ACFS snapshots.

Table 16-88 lists Oracle ACFS snapshot commands with brief descriptions. For an overview of Oracle ACFS snapshots, refer to About Oracle ACFS Snapshots.

For more information about running Oracle ACFS acfsutil commands, refer to About Using Oracle ACFS Command-Line Tools.

Table 16-88 Summary of commands for Oracle ACFS snapshots

Command	Description
acfsutil snap convert	Converts the type of an existing snapshot.
acfsutil snap create	Creates a snapshot of an Oracle ACFS file system or an existing snapshot.
acfsutil snap delete	Deletes a snapshot of an Oracle ACFS file system.
acfsutil snap duplicate apply	Updates a duplicate snapshot or file system.
acfsutil snap duplicate create	Creates a duplicate of an existing snapshot.
acfsutil snap info	Displays information about Oracle ACFS file system snapshots.
acfsutil snap link	Creates or deletes a snapshot link.
acfsutil snap quota	Sets the quota limit for a specified snapshot.
acfsutil snap remaster	Remasters a file system with a specified snapshot.
acfsutil snap rename	Renames a snapshot.

acfsutil snap convert

Purpose

Converts the type of an existing snapshot image from read-only to read-write or read-write to read-only.

Syntax and Description

acfsutil snap convert -h
acfsutil snap convert [-r|-w] snap_shot mount_point

acfsutil snap convert -h displays help text and exits.

The following table contains the options available with the acfsutil snap convert command.

Table 16-89 Options for the acfsutil snap convert command

Option	Description
`-r`	Converts snapshot to read-only snapshot.
`-w`	Converts snapshot to read-write snapshot.
`snap_shot`	Specifies the name of the snapshot to be converted.
`mount_point`	Specifies the directory where the file system is mounted.

acfsutil snap convert converts the type of an existing snapshot image from a read-only snapshot image to a read-write snapshot image, or from a read-write snapshot image to a read-only snapshot image.

The type option (-r or -w) is required for the convert operation. Specifying a type parameter that matches the type of the existing snapshot image results in no conversion and no failure. An 11.2 read-only snapshot image can be converted to a read-write snapshot image, but this conversion results in an update of the Oracle ACFS on-disk structure version. After the Oracle ACFS on-disk structure version has been updated, the updated version is not compatible with previous Oracle ACFS 11.2 versions.

Administrator privileges are required to use this command or you must be a member of the Oracle ASM administrator group.

Examples

Example 16-84 shows the use of the acfsutil snap convert command.

Example 16-84 Using the acfsutil snap convert command

$ acfsutil snap convert -w midday_test1 /acfsmounts/critical_apps

$ acfsutil snap convert -r midday_test2 /acfsmounts/critical_apps

acfsutil snap create

Purpose

Creates a read-only or read-write snapshot of an Oracle ACFS file system or an existing snapshot.

Syntax and Description

acfsutil snap create -h
acfsutil snap create [-r|-w] [-p parent_snap_shot] snap_shot mount_point

acfsutil snap create -h displays help text and exits.

The following table contains the options available with the acfsutil snap create command.

Table 16-90 Options for the acfsutil snap create command

Option	Description
`-r`	Creates a read-only snapshot. This is the default setting.
`-w`	Creates a read-write snapshot.
`snap_shot`	Specifies a name for the snapshot. The name provided must follow host operating system specific naming rules for directories. The`.ACFS/snaps` directory itself cannot be snapped.
`-p` `parent_snap_shot`	Specifies the name of an existing snapshot image within the Oracle ACFS file system.
`mount_point`	Specifies the directory where the file system is mounted.

acfsutil snap create creates a read-only or read-write snapshot of the Oracle ACFS file system mounted on mount_point or creates a snapshot of an existing snapshot if the -p option is specified. You can specify -r for read-only or -w for read-write; read-only is the default if neither -r or -w are specified.

The read-write snapshot enables the fast creation of an Oracle ACFS snapshot image that can be both read and written without impacting the state of the Oracle ACFS file system hosting the snapshot images. You can use the read-write functionality for testing new versions of application software or running test scenarios on production file data without modifying the original file system.

During the create snapshot operation duplicate data within the source file system or snapshot is copied to the new snapshot. The create operation makes a copy of a file system or snapshot whose last update was performed by an acfsutil snap duplicate apply operation. This updated file system or snapshot is known as the apply target. The data written to an apply target comes from the snapshot duplication stream of an acfsutil snap duplicate create operation. An apply target contains metadata that identifies the stream that updated the target. This metadata ensures that any future acfsutil snap duplicate apply operation for the apply target has a starting point that matches the endpoint of the previous stream that updated the target.

Snapshots are not separate file systems. The snapshot appears in the .ACFS/snaps/snapshot directory and initially is a complete replica of the file system at the time the snapshot command was given. A read-only snapshot continues to preserve that initial point-in-time view. A read-write snapshot can be modified by updates written directly to the files located within the .ACFS/snaps/snapshot hierarchy.

A symbol link (symlink) file is a pointer to a path specified at the time that the symlink is created. For any existing symlink in the source of the acfsutil snap create command, a new link is made in the snapshot; however, the stored path to the symlink target is not modified during snap creation time. When an absolute path is used as the target of the link, the link target of the snapshot still refers to the absolute path, outside the newly-created snapshot namespace. Future modifications to the targeted file can occur through the snapshot symlink, not to a new target inside the snapshot namespace. The contents of the targeted file can also be changed outside of the snapshot. Because of this behavior, you should use relative path targets for all symlinks that are within the same file system.

Any user can access the snapshot directory by specifying the path name. However, the .ACFS directory itself is hidden from directory listings of the root of the file system. This prevents recursive commands, such as rm -rf or acfsutil tag set -r, from the root of the file system inadvertently operating on snapshot files.

Snapshots usually use very little storage initially as they share file system blocks with the original file system until a file changes.

Tools such as du report the total disk space usage of the snapshotted files, which includes the storage shared with the original versions of the files. To determine the total space used for the snapshots, use the acfsutil snap info or acfsutil info fs command.

Oracle ACFS snapshots are immediately available for use after they are created. They are always online under the.ACFS/snaps directory when the original file system is mounted. No separate command is needed to mount them.

The acfsutil snap create operation fails if the cluster is in rolling migration.

Creation from an existing snapshot is not permitted if there are:

Any snapshots present in the file system that were created with the ADVM compatibility set to less than 12.1
Any snapshots of the file system that were created after ADVM compatibility was set to 12.1 but while 11.2 snapshots existed
Any snapshot deletion cleanup operations still running in the background for the above conditions

You can display pending snapshot operations with the acfsutil snap info command.

Administrator privileges are required to use this command or you must be a member of the Oracle ASM administrator group.

Examples

Example 16-85 shows the use of the acfsutil snap create command to create snapshots on a Linux platform.

Example 16-85 Using the acfsutil snap create command on Linux

$ /sbin/acfsutil snap create -w midday_test1 /acfsmounts/critical_apps

$ /sbin/acfsutil snap create -w midday_test2 /acfsmounts/critical_apps

$ /sbin/acfsutil snap create payroll_report1 /acfsmounts/critical_apps

$ /sbin/acfsutil snap create payroll_report2 /acfsmounts/critical_apps

$ ls /acfsmounts/critical_apps/.ACFS/snaps
midday_test1  midday_test2  payroll_report1  payroll_report2

Example 16-86 shows the use of the acfsutil snap create command to create snapshots on a Windows platform. This example shows the creation of a snapshot from an existing snapshot.

Example 16-86 Using the acfsutil snap create command on Windows

C:\oracle> acfsutil snap create /w snap_1 e:

C:\oracle> acfsutil snap create /w snap_1-1 /p snap_1 e:

acfsutil snap delete

Purpose

Deletes a snapshot of an Oracle ACFS file system.

Syntax and Description

acfsutil -h snap delete
acfsutil snap delete snapshot mount_point

acfsutil -h snap delete displays help text and exits.

Table 16-91 contains the options available with the acfsutil snap delete command.

Table 16-91 Options for the acfsutil snap delete command

Option	Description
`snapshot`	Specifies a name for the snapshot.
`mount_point`	Specifies the directory where the file system is mounted.

acfsutil snap delete deletes the snapshot named snapshot in the Oracle ACFS mounted on mount_point. After successful completion of the command, the representation of the snapshot in the.ACFS/snaps directory is removed. The command succeeds even if there are open files or directory references; however, storage associated with the snapshot is not released until all such references are closed.

The disk space used by the snapshot being deleted is released by a background task after the completion of the acfsutil snap delete command or after the last close of a file in the snapshot. If one of these background threads is running to clean up a deleted snapshot, then the acfsutil snap info command shows a pending delete operation. For information about the acfsutil snap info command, refer to "acfsutil snap info".

The acfsutil snap delete operation fails if the cluster is in rolling migration.

Administrator privileges are required to use this command or you must be a member of the Oracle ASM administrator group.

Examples

Example 16-87 shows the use of the acfsutil snap delete command.

Example 16-87 Using the acfsutil snap delete command

$ /sbin/acfsutil snap delete midday_test1 /acfsmounts/critical_apps
acfsutil snap delete: Snapshot operation is complete.

acfsutil snap duplicate apply

Purpose

Applies a previously created duplicated snapshot to an Oracle ACFS snapshot or file system.

Syntax and Description

acfsutil snap duplicate apply -h
acfsutil snap duplicate apply [-b | -B snap_shot] [-d trace_level] [snap_shot] mount_point

acfsutil snap duplicate apply -h displays help text and exits.

The following table contains the options available with the acfsutil snap duplicate apply command.

Table 16-92 Options for the acfsutil snap duplicate apply command

Option	Description
`—b`	Specifies that a backup snapshot is generated after a successful completion of the command. The name of the backup is generated in the format `SDBACKUP_seccnt_sourcesnap_targetsnap`, which is described in the text of this topic.
`—B snap_shot`	Specifies that a backup snapshot with the name specified is generated after a successful completion of the command.
`-d` `trace_level`	Specifies the trace level setting [0..6] for the command execution.
`snap_shot`	Specifies that the named snapshot of that file system is the target. The specified snapshot must exist and must be writable. If the snap_shot is not specified, the target for the apply operation is the file system currently mounted at the mount point
`mount_point`	Specifies the directory where the duplicate snapshot is applied.

The acfsutil snap duplicate apply command uses the snapshot duplication stream produced by acfsutil snap duplicate create to update the specified target file system or snapshot. The stream of data is read from the standard input.

If the target has never been applied to by a acfsutil snap duplicate apply operation, this is an initial apply, and the target must be initially empty. If the target has been applied to by a previous apply operation, this is an incremental apply, and the initial contents of the target must match the contents of the older snapshot used to produce the snapshot duplication stream.

If the contents of the target no longer match the older snapshot for the stream, the command returns an error and the stream is not applied. The target must not be updated by other means while the apply operation is in progress. If another update occurs, the command returns an error and stops applying the snapshot duplication stream. If the data stream being applied is identical to the last data stream applied to the specified target, the command exits without writing anything to the target with a status value of 2.

If the -b or —B option is specified, then a backup snapshot is taken of the target after the apply operation completes the update. Because the snapshot taken for an apply operation is automatically deleted when the next apply operation completes, the snapshot present is the one from the last-completed apply operation. The backup snapshot provides a known and consistent version of the target for the last successful apply operation and a comparison point to identify the in-progress changes made by a acfsutil snap duplicate apply operation.

If a name was not specified with the —B option, then a backup snapshot has a name of the form SDBACKUP_seccnt_sourcesnap or SDBACKUP_seccnt_sourcesnap_targetsnap. In the name string, seccnt is a local timestamp (number of seconds since the Unix epoch) indicating the point at which the target was captured by the backup snapshot. sourcesnap indicates the snapshot from the source file system that was applied by the last completed acfsutil snap duplicate apply operation. targetsnap, if present, indicates the snapshot name in the target file system that was updated by the last completed acfsutil snap duplicate apply operation.

System administrator (root) privileges are required to use this command.

The acfsutil snap duplicate apply command produces an exit status of 0 on success, 1 if a fatal error occurs, or 2 if the data stream read matches the last previous data stream applied to the specified target.

For information about displaying snapshot information, refer to "acfsutil snap info".

Examples

Example 16-88 shows the use of the acfsutil snap duplicate apply command. Because the command expects to read a binary data stream from its standard input, this command is normally used in a pipeline with the acfsutil snap duplicate create command, as shown in the example.

Example 16-88 Using the acfsutil snap duplicate apply command

$ /sbin/acfsutil snap duplicate create new_snapshot_name /acfsmounts/critical_apps | \
      /sbin/acfsutil snap duplicate apply /acfsmounts/ca_backups

acfsutil snap duplicate create

Purpose

Creates a duplicate snapshot of an existing snapshot.

Syntax and Description

acfsutil snap duplicate create -h
acfsutil snap duplicate create [-r] [-d trace_level] [-p parent_snapshot]
                               [-i old_snapshot] new_snapshot mount_point

acfsutil snap duplicate create -h displays help text and exits.

Table 16-93 contains the options available with the acfsutil snap duplicate create command.

Table 16-93 Options for the acfsutil snap duplicate create command

Option	Description
`-r`	Specifies to mark the snap duplication stream as a restart stream. This option is intended for use on the second or later attempt to create and apply a given stream. This option might be necessary if an earlier attempt terminated prematurely.
`-d` trace_level	Specifies the trace level setting [0..6] for the command execution.
`-p` `parent_snapshot`	Specifies the name of a parent snapshot image of which both the `old_snapshot` and `new_snapshot` are children. This option ensures that both snapshots are children (snap-of-snap) of the same snapshot. If the `—p` option is not specfied, then either the `new_snapshot` must be a child of the `old_snapshot`, or the two snapshots must be snapshots of the base file system at the specified mount point.
`—i` `old_snapshot`	Specifies the name of an existing snapshot.
`new_snapshot`	Specifies a name for the new snapshot.
`mount_point`	Specifies the directory where the file system is mounted. This is the mount point of the file system of which the snapshots were taken.

The acfsutil snap duplicate create command externalizes snapshot-related data in a form suitable for use by snap duplicate apply to create a different instance of a compatible snapshot. This externalized data is called a snapshot duplication stream.

If only the new snapshot name is specified, then this command encodes the entire contents of the named snapshot (the difference between an empty snapshot and this snapshot). This is an initial snap duplicate operation.

If both the old snapshot name and new snapshot name are given, this command encodes only the differences between the two snapshots. This is an incremental snap duplicate operation.

In either case, this command writes the snapshot duplication stream to its standard output.

System administrator (root) privileges are required to use this command.

The acfsutil snap duplicate create command produces an exit status of 0 on success or 1 if a fatal error occurs.

For information about displaying snapshot information, refer to "acfsutil snap info".

Examples

Example 16-89 shows the use of the acfsutil snap duplicate create command. Because the command writes a binary data stream to its standard output, this command is normally used in a pipeline with the acfsutil snap duplicate apply command, as shown in the example.

Example 16-89 Using the acfsutil snap duplicate create command

$ /sbin/acfsutil snap duplicate create new_snapshot_name /acfsmounts/critical_apps | \
      /sbin/acfsutil snap duplicate apply /acfsmounts/ca_backups

acfsutil snap info

Purpose

Displays information about Oracle ACFS file system snapshots.

Syntax and Description

acfsutil snap info -h
acfsutil snap info [-t] [snap_shot] mount_point

acfsutil snap info -h displays help text and exits.

The following table contains the options available with the acfsutil snap info command.

Table 16-94 Options for the acfsutil snap info command

Option	Description
`-t`	Displays a tree structure for the specified snapshot and mount point.
`snap_shot`	Specifies a name for the snapshot.
`mount_point`	Specifies the directory where the file system is mounted.

The acfsutil snap info command displays information about an individual specified snapshot or all snapshots in the specified Oracle ACFS file system.

The snapshot name, snapshot type, parent name, creation date and time, and space used are displayed. The parent name is either the mount point, or the parent snapshot if the snapshot was created from an existing snapshot.

The type of a snapshot is indicated by one or more of the following strings. Any relevant strings are displayed on the same line.

RO - snapshot is read-only
RW - snapshot is read-write
Primary - snapshot is a primary storage location for replication
Standby - snapshot is a standby storage location for replication
REPL - snapshot is an internal snapshot used by replication
DUP - snapshot or its parent is a target of snap duplicate apply

The appearance of the string REPL is not related to whether a snapshot is a replication primary or standby. This string appears only if the snapshot is one that was created by replication for its own internal use.

The string DUP appears if either of the following conditions is true:

The snapshot is in use as the target of an apply operation.
The parent of the snapshot was in use as the target of an apply operation at the point when the snapshot was created.

The snapshot space usage amount includes snapshot metadata. If all the files are deleted from a snapshot, some metadata still remains and that amount is displayed with acfsutil snap info.

When using an accelerator volume, the reported snapshot space usage amount can include space that is in use on the accelerator volume.

To reclaim the disk space used by snapshots, delete the snapshots. Deleting the files within the snapshots may not reclaim this disk space.

The acfsutil snap info command shows the status of a snapshot that is in the process of being deleted as follows:

When waiting on files to be closed:

snapshot_name (delete waiting for last close)

When freeing the storage for the snapshot in the background:
```
snapshot_name (delete in progress)
```

Oracle ACFS caches and asynchronously updates snapshot storage usage statistics. If an Oracle ASM instance is killed, power is lost to the machine, or the Oracle ACFS file system goes offline for any reason, one of these cached updates may be lost. This loss can result in the display of a message similar to Reported snapshot space usage is inaccurate when acfsutil snap info is run.

Examples

Example 16-90 shows the use of the acfsutil snap info command on a Linux platform. The command output contains information about a read-only (RO) snapshot, a read-write (RW) snapshot with quota information, a snapshot in delete waiting for last close status, and a snapshot in delete in progress status. After a delete operation completes on a snapshot and the background process finishes the clean up of a deleted snapshot, messages about the delete operation do not appear in the output.

Example 16-90 Using the acfsutil snap info command on Linux

$ /sbin/acfsutil snap info /acfsmounts/critical_apps/
snapshot name:               midday_test (delete waiting for last close)
snapshot creation time:      Tue Apr  5 10:52:55 2016


snapshot name:               payroll_report1
snapshot location:           /acfsmounts/critical_apps/.ACFS/snaps/payroll_report1
RO snapshot or RW snapshot:  RW
parent name:                 /acfsmounts/critical_apps/
snapshot creation time:      Tue Apr  5 10:52:59 2016
storage added to snapshot:   95514624   (  91.09 MB )

quota:                       104857600  ( 100.00 MB )
quota usage:                 91 %


snapshot name:               midday_test2 (delete in progress)
snapshot creation time:      Mon Apr 11 11:40:13 2016


snapshot name:               payroll_report2
snapshot location:           /acfsmounts/critical_apps/.ACFS/snaps/payroll_report2
RO snapshot or RW snapshot:  RO
parent name:                 midday_test2
snapshot creation time:      Mon Apr 11 12:05:42 2016
storage added to snapshot:   1081344   (   1.03 MB )


    number of snapshots:  3 (active)
                          1 (delete in progress)
        snapshot space usage: 102084608  (  97.36 MB )


$ /sbin/acfsutil snap info -t /acfsmounts/critical_apps
/acfsmounts/critical_apps RW    
midday_test               RW    /acfsmounts/critical_apps
payroll_report1           RW    /acfsmounts/critical_apps
midday_test2              RW    /acfsmounts/critical_apps
payroll_report2           RO    midday_test2 


$ /sbin/acfsutil snap info -t midday_test2 /acfsmounts/critical_apps
midday_test2              RW    
payroll_report2           RO    midday_test2

Example 16-91 shows the use of the acfsutil snap info command on a Windows platform.

Example 16-91 Using the acfsutil snap info command on Windows

C:\oracle> acfsutil snap info e:
snapshot name:               MIDDAY_TEST (delete waiting for last close)
snapshot creation time:      Wed Apr 13 12:44:15 2016

snapshot name:               PAYROLL_REPORT1
snapshot location:           e:\.ACFS\snaps\PAYROLL_REPORT1
RO snapshot or RW snapshot:  RW
parent name:                 e:
snapshot creation time:      Wed Apr 13 12:45:00 2016
storage added to snapshot:   18866176   (  17.99 MB )

quota:                       104857600  ( 100.00 MB )
quota usage:                 17 %

snapshot name:               MIDDAY_TEST2 (delete in progress)
snapshot creation time:      Wed Apr 13 12:48:07 2016


snapshot name:               PAYROLL_REPORT2
snapshot location:           e:\.ACFS\snaps\PAYROLL_REPORT2
RO snapshot or RW snapshot:  RO
parent name:                 MIDDAY_TEST2
snapshot creation time:      Wed Apr 13 12:50:34 2016
storage added to snapshot:   1081344   (   1.03 MB )


    number of snapshots:  3 (active)
                          1 (delete in progress)
        snapshot space usage: 362557440  ( 345.76 MB )


C:\oracle> acfsutil snap info /t e:
e:                        RW    
MIDDAY_TEST               RW    e:
PAYROLL_REPORT1           RW    e:
MIDDAY_TEST2              RW    e:
PAYROLL_REPORT2           RO    MIDDAY_TEST2


C:\oracle> acfsutil snap info /t MIDDAY_TEST2 e:
MIDDAY_TEST2              RW    
PAYROLL_REPORT2           RO    MIDDAY_TEST2

acfsutil snap link

Purpose

Creates or deletes a snapshot link.

Syntax and Description

acfsutil snap link -h
acfsutil snap link -s snap_shot path_to_link
acfsutil snap link -s snap_shot -d path_to_link

acfsutil snap link -h displays help text and exits.

The following table contains the options available with the acfsutil snap link command.

Table 16-95 Options for the acfsutil snap link command

Option	Description
`—s snap_shot`	Specifies the name of an Oracle ACFS snapshot in the Oracle ACFS file system.
`-d`	Deletes the specified snapshot link.
`path_to_link`	Specifies a directory in the Oracle ACFS file system.

You can create or delete snapshot links with the acfsutil snap link command. A snapshot link provides access to the contents of a snapshot using an alternate path which does not include the .ACFS/snaps directory, the default location where snapshot are created.

A snapshot link is a specialized hard link that requires that only one snapshot link may exist for a snapshot. Snapshot links can only be created in the primary file system, not within another snapshot. Snapshot links can be recreated to change the name or location of the snapshot link. The name that you specify for a snapshot link does not have to be the same as the name or the snapshot to which it links. A snapshot link does require on disk changes and the COMPATIBLE.ADVM disk group attribute must be set to 18.0 or higher. Snapshot links can only be created and deleted with the acfsutil snap link command. The links cannot be moved or removed with normal operating system commands.

You can display information about snapshot links with the acfsutil snap info command. You can use acfsutil snap info snap_shot to determine whether the specified snapshot has a link.

Examples

The following example shows the use of the acfsutil snap link command. After a new snapshot is created, a link is created to the new snapshot.

Example 16-92 Using the acfsutil snap link command

$ /sbin/acfsutil snap create -w snap1 /usmmnt  
acfsutil snap create: Snapshot operation is complete.

$ /sbin/acfsutil snap link -s snap1 /usmmnt/dir1/link
acfsutil snap link: Snapshot operation is complete.

$ /sbin/acfsutil snap info /usmmnt
snapshot name:               snap1
snapshot location:           /usmmnt/.ACFS/snaps/snap1
snapshot link:               /usmmnt/dir1/link
RO snapshot or RW snapshot:  RW
parent name:                 /usmmnt
...

acfsutil snap quota

Purpose

Sets the quota limit for a specified snapshot.

Syntax and Description

acfsutil -h snap quota

acfsutil snap quota [+|-]n[K|M|G|T|P] snapshot mount_point

acfsutil —h snap quota displays help text and exits.

The following table contains the options available with the acfsutil snap quota command.

Table 16-96 Options for the acfsutil snap quota command

Option Description

Option	Description
[`+`\|`-`]`n` `K`\|`M`\|`G`\|`T`\|`P`	Specifies the quota limit size for the Oracle ACFS snapshot where `n` is a valid positive whole number greater than zero. The number can be preceded by a `+` or - to indicate the amount to add or decrease. If no operand exists, the new size is the absolute size. Specifies that the integer supplied for size is in the units of `K` (Kilobytes), `M` (Megabytes), `G` (Gigabytes), `T` (Terabytes), or `P` (Petabytes). If the unit indicator is specified, then it must be appended to the integer. If omitted, the default unit is bytes.
`snapshot`	Specifies a name of the snapshot.
`mount_point`	Specifies the directory where the file system is mounted.

[+|-]n

K|M|G|T|P

Specifies the quota limit size for the Oracle ACFS snapshot where n is a valid positive whole number greater than zero. The number can be preceded by a + or - to indicate the amount to add or decrease. If no operand exists, the new size is the absolute size.

Specifies that the integer supplied for size is in the units of K (Kilobytes), M (Megabytes), G (Gigabytes), T (Terabytes), or P (Petabytes). If the unit indicator is specified, then it must be appended to the integer. If omitted, the default unit is bytes.

snapshot

Specifies a name of the snapshot.

mount_point

Specifies the directory where the file system is mounted.

The acfsutil snap quota command sets the quota limit for a specified snapshot on the specified Oracle ACFS file system.

The quota can be larger than the size of the file system because a file system can be resized or automatically resized.

The quota limit specified does not reserve space. The quota only establishes an upper limit on the amount of storage that can be added to the snapshot.

Only snapshots created after ADVM compatibility (COMPATIBLE.ADVM) has been set to 12.2 or greater have storage accounting tracking and the ability to have quotas set.

Snapshots can be converted from read-write (RW) to read-only (RO) and vice versa. Both RW and RO snapshots can have a quota.

There is a grace period and advanced warnings for quota usage. A warning message is written to both the alert log and the console if the requested storage allocation causes the local storage usage to be near or exceeding more than 90% of the quota. If an allocation exceeds the quota, then the write or other modifying operation fails as EDQUOT, or it may fail as ENOSPC, depending whether the quota limit is set larger than the size of the file system.

System administrator (root) privileges are required to use this command.

You can display snapshot information, including the quota limit and quota usage percentage, with the acfsutil snap info command. For information about acfsutil snap info, refer to "acfsutil snap info".

Examples

The following example shows the use of the acfsutil snap quota command.

Example 16-93 Using the acfsutil snap quota command

$ /sbin/acfsutil snap quota +500M snap_test /acfsmounts/acfs1

acfsutil snap remaster

Purpose

Remasters an Oracle ACFS file system with a snapshot.

Syntax and Description

acfsutil snap remaster -h
acfsutil snap remaster { snapshot | -c } -f volume

acfsutil snap remaster -h displays help text and exits.

Table 16-97 contains the options available with the acfsutil snap remaster command.

Table 16-97 Options for the acfsutil snap remaster command

Option	Description
`—c`	Continues the interrupted remaster operation. After the command has started, the remastering must run to completion.
`—f`	Forces the operation and does not prompt for questions.
`snapshot`	Specifies the name of an existing snapshot.
`volume`	Specifies specifies the primary Oracle ADVM volume device path for the file system.

This command accepts a snapshot name or the —c option.

The specified snapshot is used for the base of the file system, replacing the current base of the file system. Using an existing read-only or read-write snapshot, the command reintegrates the snapshot extents into the base of the current file system creating a new remastered file system with the point in time state of the snapshot. The remastered file system is left with no snapshots. This operation must be done on an unmounted file system and it cannot be reversed.

Use the -c option, instead of the snapshot name, to complete an interrupted snapshot remastering.

You cannot remaster a file system on which replication, security, or encryption is running. You must terminate replication, security, or encryption before running the acfsutil snap remaster command. In addition, you cannot remaster a file system with plugins enabled.

Administrator privileges are required to use this command or you must be a member of the Oracle ASM administrator group.

Examples

Example 16-94 shows the use of the acfsutil snap remaster command.

Example 16-94 Using the acfsutil snap remaster command

$ /sbin/acfsutil snap remaster snapshot volume

acfsutil snap rename

Purpose

Renames an Oracle ACFS snapshot.

Syntax and Description

acfsutil snap rename -h
acfsutil snap rename old_snapshot new_snapshot mount_point

acfsutil snap rename -h displays help text and exits.

Table 16-98 contains the options available with the acfsutil snap duplicate create command.

Table 16-98 Options for the acfsutil snap rename command

Option	Description
`old_snapshot`	Specifies the name of an existing snapshot.
`new_snapshot`	Specifies a name for the new snapshot.
`mount_point`	Specifies the directory where the file system is mounted.

The acfsutil snap renamecommand is used to safely rename an existing snapshot in the filesystem.

While a snapshot with open files can be renamed, applications accessing files in that snapshot experience the same behavior as operating in a non-snap directory tree in which one of the parent directories was renamed.

Renaming snapshots used in conjunction with pluggable databases (PDBs) is not supported at this time. Such a snapshot should not be renamed.

Replication-specific snapshots cannot be renamed as this may cause complications and inconsistencies with replication.

Administrator privileges are required to use this command or you must be a member of the Oracle ASM administrator group.

For information about displaying snapshot information, refer to "acfsutil snap info".

Examples

Example 16-95 shows the use of the acfsutil snap rename command.

Example 16-95 Using the acfsutil snap rename command

$ /sbin/acfsutil snap rename old_snapshot_name new_snapshot_name /acfsmounts/critical_apps