16.1 Basic Steps to Manage Oracle ACFS Systems

This topic provides an overview of the basic steps when managing Oracle ACFS file systems using command-line utilities.

The examples in this section show operating system commands that are run in a Linux environment system. ASMCMD commands manage the Oracle ADVM volumes, but you can also use SQL*PLus and Oracle ASM Configuration Assistant (ASMCA) to manage volumes.

This section contains these topics:

16.1.1 About Using Oracle ACFS Command-Line Tools

This topic provides an overview of the use of Oracle ACFS acfsutil commands.

The discussions include:

  • Privileges to Run Oracle ACFS acfsutil Commands

  • Displaying Help for Oracle ACFS acfsutil Commands

  • Running Oracle ACFS acfsutil Commands on Windows

  • Displaying Oracle ACFS Version Information

  • Managing Trace File Space for acfsutil Commands

Privileges to Run Oracle ACFS acfsutil Commands

To run many Oracle ACFS acfsutil commands, you must be a system administrator or an Oracle ASM administrator user that has been enabled to run the commands. These privileges are described as follows:

On Non-Windows systems:

  • For system administrator privileges, you must be the root user.

  • For Oracle ASM administrator user privileges, you must belong to the OSASM group and the oinstall group (for the OINSTALL privilege ).

On Windows systems:

  • For system administrator privileges, you must belong to the Administrators group.

  • For Oracle ASM administrator user privileges, you must belong to the ORA_ASMADMIN group and the ORA_CRS_USERS group.

Displaying Help for Oracle ACFS acfsutil Commands

You can display help and usage text for Oracle ACFS acfsutil commands with the h option. When you include a command or a subcommand with the command, the help and usage display is specific to the command and subcommand entered.

The following example illustrates several different ways to display help and usage text, from the most general to more specific. This example shows the —h format to display help on a non-Windows platform. On Windows, use /h in place of —h.

Example 16-1 Displaying help for Oracle ACFS acfsutil commands

$ /sbin/acfsutil -h

$ /sbin/acfsutil -h compress
$ /sbin/acfsutil compress -h

$ /sbin/acfsutil -h repl info 
$ /sbin/acfsutil repl info -h

$ /sbin/acfsutil -h sec admin info
$ /sbin/acfsutil sec admin info -h

Running Oracle ACFS acfsutil Commands on Windows

When the options are specified with Oracle ACFS acfsutil commands on a Windows platform, use / in place of - with the option. For example, you can display help for acfsutil commands on a Linux platform with acfsutil -h. On a Windows platform, use acfsutil /h.

A mount point on a Windows operating system can be a just the drive letter (M:) or a directory including the drive letter (M:\my_mount_point).

When an acfsutil command on Windows targets the root of the file system that is mounted on a drive letter, include the backslash and a period (\.) with the drive letter (P:\.) to avoid the possibility of triggering a Windows path substitution to the last accessed path on the specified drive. For example:

C:\oracle> acfsutil info fs P:\.

Displaying Oracle ACFS Version Information

You can run acfsutil version to display the Oracle ACFS version. For example:

$ /sbin/acfsutil version
acfsutil version: 12.2.0.0.3

Managing Trace Files for acfsutil Commands

The Automatic Diagnostic Repository (ADR) generates a separate internal file for each acfsutil command invocation to trace the operation of the command. The space consumed by these trace files can increase significantly, and some features, such as snapshot-based replication, may generate a significant number of trace files.

To limit the number of trace files and the space consumed by them, you can set policy attributes with the Automatic Diagnostic Repository Command Interpreter (ADRCI) utility to purge trace files after a specified retention period. ADRCI considers trace files to be short-lived files and the retention period is controlled by the setting of the SHORTP_POLICY attribute. You can view the current retention period for these trace files with the ADRCI show control command.

By default, the short-lived files are retained for 720 hours (30 days). The value in hours specifies the number of hours after creation when a given file is eligible for purging. To limit the number of these files and the space consumed by them, you can update the number of hours set for the SHORTP_POLICY retention period, such as 240 hours (10 days).

The following steps summarize how to update the retention period for short-lived trace files.

  • Start the Automatic Diagnostic Repository Command Interpreter (ADRCI) utility.

    $ adcri

  • Display the ADR home directory paths (ADR homes):

    ADRCI> show homes

  • If more than one home is shown, then set the appropriate home for the trace files you want to administer:

    ADRCI> set homepath my_specified_homepath

  • Display the current configuration values.

    ADRCI> show control

  • Update a specific ADRCI configuration value. For example, set SHORTP_POLICY to 240 hours (10 days).

    In the displayed show control output, check the value of the SHORTP_POLICY attribute, which is the retention period in hours for short-lived files. If necessary, set a new retention period for short-lived trace files with the following:

    ADRCI> set control (SHORTP_POLICY=240)

If you want to start an immediate purge of the trace files in the current ADR home path, you can use the following command:

ADRCI> purge -type TRACE -age number_of_minutes

The value number_of_minutes controls which files are purged based on the age of the files. Files older than the specified number of minutes are targeted for the purge operation.

See Also:

16.1.2 Creating an Oracle ACFS File System

You can create an Oracle ACFS file system using the steps in this topic.

To create and verify a file system, perform the following steps:

  1. Create an Oracle ADVM volume in a mounted disk group with the ASMCMD volcreate command.

    The compatibility parameters COMPATIBLE.ASM and COMPATIBLE.ADVM must be set to 11.2 or higher for the disk group to contain an Oracle ADVM volume. To use Oracle ACFS encryption, replication, security, or tagging, the disk group on which the volume is created for the file system must have compatibility attributes for ASM and ADVM set to 11.2.0.2 or higher.

    Start ASMCMD connected to the Oracle ASM instance. You must be a user in the OSASM operating system group.

    When configuring Oracle ADVM volume devices within a disk group, Oracle recommends assigning the Oracle Grid Infrastructure user and Oracle ASM administrator roles to users who have root privileges.

    To create a volume:

    ASMCMD [+] > volcreate -G data -s 10G volume1
    

    When creating an Oracle ADVM volume, a volume device name is created that includes a unique Oracle ADVM persistent disk group number. The volume device file functions in the same manner as any other disk or logical volume to mount file systems or for applications to use directly.

    The format of the volume name is platform-specific.

  2. Determine the device name of the volume that was created.

    You can determine the volume device name with the ASMCMD volinfo command or from the VOLUME_DEVICE column in the V$ASM_VOLUME view.

    For example:

    ASMCMD [+] > volinfo -G data volume1
    Diskgroup Name: DATA
    
             Volume Name: VOLUME1
             Volume Device: /dev/asm/volume1-123
             State: ENABLED
         ... 
    
    SQL> SELECT volume_name, volume_device FROM V$ASM_VOLUME 
         WHERE volume_name ='VOLUME1';
    
    VOLUME_NAME        VOLUME_DEVICE
    -----------------  --------------------------------------
    VOLUME1            /dev/asm/volume1-123
    
  3. Create a file system with the Oracle ACFS mkfs command.

    Create a file system using an existing volume device.

    For example:

    $ /sbin/mkfs -t acfs /dev/asm/volume1-123
    
    mkfs.acfs: version                   = 11.2.0.1.0.0
    mkfs.acfs: on-disk version           = 39.0
    mkfs.acfs: volume                    = /dev/asm/volume1-123
    mkfs.acfs: volume size               = 10737418240
    mkfs.acfs: Format complete.
    

    The root privilege is not required to run mkfs. The ownership of the volume device file dictates who can run this command.

  4. Optionally register the file system with the acfsutil registry command.

    For example:

    $ /sbin/acfsutil registry -a /dev/asm/volume1-123 /acfsmounts/acfs1
    
    acfsutil registry: mount point /acfsmounts/acfs1 successfully added 
      to Oracle Registry
    

    The root or asmadmin privileges are required to modify the registry. The Windows Administrator privilege is equivalent to the root privilege on Linux.

    Registering a file system is optional. After registering an Oracle ACFS file system in the cluster mount registry, the file system is mounted automatically on each cluster member listed in the registry entry during the next registry check action. This automatic process runs every 30 seconds and eliminates the requirement to manually mount the file system on each member of the cluster.

    Registering an Oracle ACFS file system also causes the file system to be mounted automatically whenever Oracle Clusterware or the system is restarted.

    Note:

    In an Oracle Grid Infrastructure Clusterware configuration, you can run srvctl add filesystem to automount a file system; this method is required when an Oracle Database home is installed on an Oracle ACFS file system. However, that file system should not be added to the registry.

    Note:

    Oracle ACFS registration (acfsutil registry) is not supported in an Oracle Restart (standalone) configuration, which is a single-instance (non-clustered) environment.

  5. Mount the file system with the Oracle ACFS mount command. You can mount a file system before or after registering the file system. If the file system has been registered, you can wait for the file system to be mounted automatically.

    For example:

    # /bin/mount -t acfs /dev/asm/volume1-123 /acfsmounts/acfs1
    

    The root privilege is required to run the mount command and the Windows Administrator privilege is required to run the acfsmountvol command.

    After the file system has been mounted, ensure that the permissions are set to allow access to the file system for the appropriate users. For example:

    # chown -R oracle:dba /acfsmounts/acfs1
    
  6. Create a test file in the file system.

    The user that creates the test file should be a user that is intended to access the file system. This test ensures that the appropriate user can write to the file system.

    For example:

    $ echo "Oracle ACFS File System" > /acfsmounts/acfs1/myfile
    
  7. List the contents of the test file that was created in the file system.

    For example:

    $ cat /acfsmounts/acfs1/myfile
    Oracle ACFS File System

See Also:

16.1.3 Accessing an Oracle ACFS File System on a Different Node in the Cluster

If the node is part of a cluster, perform the following steps on node 2 to view the test file you created on node 1.

Note:

If the file system has been registered with the Oracle ACFS mount registry, you can skip steps 1 to 3.

  1. Enable the volume that was previously created and enabled on node 1.

    Start ASMCMD connected to the Oracle ASM instance. You must be a user in the OSASM operating system group.

    For example:

    ASMCMD [+] > volenable -G data volume1
    
  2. View information about the volume that you created on node 1.

    For example:

    ASMCMD [+] > volinfo -G data volume1
    
  3. Mount the file system using the Oracle ACFS mount command.

    For example:

    # /bin/mount -t acfs /dev/asm/volume1-123 /acfsmounts/acfs1
    

    The root privilege is required run the mount command and the Windows Administrator privilege is required to run the acfsmountvol command.

    After the file system has been mounted, ensure that the permissions are set to allow access for the appropriate users.

  4. List the contents of the test file you previously created on the file system.

    For example:

    $ cat /acfsmounts/acfs1/myfile
    Oracle ACFS File System
    

    The contents should match the file created previously on node 1.

See Also:

16.1.4 Managing Oracle ACFS Snapshots

To create and verify a snapshot on node 1:

  1. Create snapshot of the new file system created on node 1.

    For example:

    $ /sbin/acfsutil snap create mysnapshot_20090725 /acfsmounts/acfs1
    

    See "acfsutil snap create".

  2. Update the test file in the file system so that it is different than the snapshot.

    For example:

    $ echo "Modifying a file in Oracle ACFS File System" > /acfsmounts/acfs1/myfile
    
  3. List the contents of the test file and the snapshot view of the test file.

    For example:

    $ cat /acfsmounts/acfs1/myfile
    
    $ cat /acfsmounts/acfs1/.ACFS/snaps/mysnapshot_20090725/myfile
    

    The contents of the test file and snapshot should be different. If node 1 is in a cluster, then you can perform the same list operation on node 2.

16.1.5 Securing Oracle ACFS File Systems

The basic operations to manage security for an Oracle ACFS file system on Linux are discussed in this topic.

The scenario in this topic shows how to use Oracle ACFS security to ensure that only the maintenance user can access medical history files during the maintenance period. Oracle ACFS encryption is also enabled on the same file system.

In this scenario, the disk group on which the volume is created for the file system has compatibility attributes for ASM and ADVM set to 11.2.0.3 or higher.

For the examples in this section, various operating system users, operating system groups, and directories must exist.

The basic steps to manage security are:

  1. Initialize security for Oracle ACFS.

    Run the acfsutil sec init command to configure storage for security credentials and identify an operating system user as the first security administrator and the operating system security group. The security administrator must belong to the operating system group. This command must be run before any other security command and requires root or Windows Administrator privileges to run.

    The acfsutil sec init command is only run once to set up Oracle ACFS security for each cluster and can be run from any node in the cluster. Other security commands can also be run from any node in a cluster. Security administrators are common for all Oracle ACFS file systems in a cluster.

    For example, the following command initializes security for a cluster and creates the first security administrator (medHistAdmin1).

    # /sbin/acfsutil sec init -u medHistAdmin1 -g medHistAdminGrp
    

    The medHistAdmin1 security administrator must belong to the medHistAdminGrp operating system group. That group is identified as the security group for the security administrators.

    When the root user or Windows Administrator user runs the command, the user assigns a security password to the security administrator. The first security administrator can change the password with the acfsutil sec admin password command.

    All acfsutil sec commands (other than acfsutil sec init) must be run by an Oracle ACFS security administrator and the administrator is prompted for the security administrator's password when each command is run.

    Note:

    When prompting for the security administrator's password, the following text displays: Realm management password

    The password required is the Oracle ACFS security administrator's password, not the operating system password of the user.

    Security administrators are allowed to browse all directories in an Oracle ACFS file system whether they have the underlying operating system permissions and whether any realm checks allow it. This functionality enables a security administrator to check the location of the files when securing them with Oracle ACFS security realms. However, a security administrator cannot view the contents of individual files without the appropriate operating system and security realm permissions.

  2. Add additional security administrators as necessary.

    The first security administrator can add additional security administrators to administer Oracle ACFS security with the acfsutil sec admin add command.

    For example, add a new security administrator medHistAdmin2.

    $ /sbin/acfsutil sec admin add medHistAdmin2
    

    The medHistAdmin2 user must belong to the operating system group (medHistAdminGrp) identified as the security administrator group with the acfsutil sec init command.

    The medHistAdmin2 security administrator should change the assigned temporary security password with the acfsutil sec admin password command. The medHistAdmin2 administrator can add new security administrators.

  3. Prepare an Oracle ACFS file system for security.

    Run the acfsutil sec prepare on an Oracle ACFS file system before adding any security realms.

    For example, prepare the Oracle ACFS file system mounted on /acfsmounts/acfs1 for Oracle ACFS security.

    $ /sbin/acfsutil sec prepare -m /acfsmounts/acfs1
    

    By default, security is enabled for a file system after running this command. You can explicitly disable or enable security with the acfsutil sec disable or acfsutil sec enable commands.

    This command automatically creates several security realms, such as the SYSTEM_BackupOperators security realm. Administrators can add users to the SYSTEM_BackupOperators realm which gives those users permissions to make backups of realm-secured files in the Oracle ACFS file system.

  4. Provide encryption for this file system.

    Encrypting the file system is optional, but is enabled in this scenario.

    1. First, run the acfsutil encr init command to initialize encryption and create the storage necessary for the encryption keys. This command must be run one time for each cluster on which encryption is set up.

      For example, the following command initializes encryption for a cluster.

      # /sbin/acfsutil encr init
      

      This command must be run before any other encryption command and requires root or administrator privileges to run.

    2. Next, run the acfsutil encr set command to set encryption for the Oracle ACFS file system.

      For example, the following command sets encryption for the file system mounted on the /acfsmounts/acfs1 directory.

      # /sbin/acfsutil encr set -m /acfsmounts/acfs1/
      

      The acfsutil encr set command transparently generates a volume encryption key which is stored in the key store that was previously configured with the acfsutil encr init command. This command requires root or administrator privileges to run.

  5. Create a security realm on the file system.

    Run the acfsutil sec realm create command to create a security realm for a file system.

    For example, create a security realm named medHistRealm which contains medical records files with all files encrypted in the realm.

    $ /sbin/acfsutil sec realm create medHistRealm -m /acfsmounts/acfs1/ 
                                                   -e on -a AES -k 128
    

    The -e option specifies that all the files in the realm are encrypted with the AES algorithm and the key length set to 128 bits. The file system must first be prepared for encryption with the acfsutil encr init and acfsutil encr set commands. You do not have to enter the same value for the -k option with acfsutil sec realm create as you have entered with the acfsutil encr set command.

  6. Create security rules.

    Run the acfsutil sec rule create command to create rules which determine access to the files and directories of a security realm.

    For example, create rules that can enable the medMaintenance user to access medical records for the time period 10 PM to 2 AM for file maintenance. Also, create rules that can deny operations during the time period 8 AM to 9 AM and deny operations to the medBrowse user.

    $ /sbin/acfsutil sec rule create medHistRule1a -m /acfsmounts/acfs1/
          -t time 22:00:00,02:00:00 -o ALLOW
    
    $ /sbin/acfsutil sec rule create medHistRule1b -m /acfsmounts/acfs1/
          -t username medMaintenance -o ALLOW
    
    $ /sbin/acfsutil sec rule create medHistRule1c -m /acfsmounts/acfs1/ 
          -t time 08:00:00,09:00:00 -o DENY
    
    $ /sbin/acfsutil sec rule create medHistRule1d -m /acfsmounts/acfs1/ 
          -t username medBrowse -o DENY
    

    You can edit rules with the acfsutil sec rule edit command.

  7. Create security rule sets and add rules to rule sets.

    Run the acfsutil sec ruleset create command to create rule sets to which rules can be added.

    For example, create rule sets named medRuleSet1 and medRuleSet2 that include rules for operations on the files and directories of the security medHistRealm realm.

    $ /sbin/acfsutil sec ruleset create medRuleSet1 -m /acfsmounts/acfs1/
    
    $ /sbin/acfsutil sec ruleset create medRuleSet2 -m /acfsmounts/acfs1/
    

    Add existing rules to the rule sets.

    $ /sbin/acfsutil sec ruleset edit medRuleSet1 -m /acfsmounts/acfs1/ 
               -a medHistRule1a,medHistRule1b -o ALL_TRUE
    
    $ /sbin/acfsutil sec ruleset edit medRuleSet2 –m /acfsmounts/acfs1/ 
               -a medHistRule1c,medHistRule1d -o ALL_TRUE
    

    The ALL_TRUE option is the default action, but is added here to emphasize that both rules in each rule set must be true.

  8. Add objects to a security realm.

    Run the acfsutil sec realm add command to add objects, such as command rules, rule sets, and files, to a security realm. For example, add the medRuleSet1 and medRuleSet2 rule sets and all the files in the /acfsmounts/acfs1/medicalrecords directory to the medHistRealm.

    When adding a rule set to a realm, the rule set is added with a command rule, such as DELETEFILE:medRuleSet1. Only one rule set can be included with each command rule. To display a list of the command rules, use acfsutil sec info with the -c option.

    The following acfsutil sec realm add command enables the medMaintenance user to delete medical records during the time period 10 PM to 2 AM, but blocks writing to files during 8 AM to 9 AM.

    $ /sbin/acfsutil sec realm add medHistRealm -m /acfsmounts/acfs1/ 
            -l DELETEFILE:medRuleSet1 
            -f -r /acfsmounts/acfs1/medicalrecords
    

    This acfsutil sec realm add command prevents the medBrowse user from writing or deleting medical records anytime.

    $ /sbin/acfsutil sec realm add medHistRealm -m /acfsmounts/acfs1/ 
            -l WRITE:medRuleSet2 
            -f -r /acfsmounts/acfs1/medicalrecords
    

    This acfsutil sec realm add command adds backup operators to the SYSTEM_BackupOperators security realm that was automatically created with the acfsutil sec prepare command.

    $ /sbin/acfsutil sec realm add SYSTEM_BackupOperators -m /acfsmounts/acfs1/ 
            -G sysBackupGrp
    

    Users that belong to the sysBackupGrp operating system group can now make backups of realm-secured files in the Oracle ACFS file system.

  9. Display security information.

    Run the acfsutil sec info command to display information for a security realm. For example, display security information for the medHistRealm realm.

    $ /sbin/acfsutil sec info -m /acfsmounts/acfs1/ –n medHistRealm
    

    To display the security realms to which a file or a directory belongs, run the acfsutil sec info file command. For example:

    $ /sbin/acfsutil sec info file -m /acfsmounts/acfs1/
                                   /acfsmounts/acfs1/medicalrecords
    
  10. Save security metadata as a backup.

    Run the acfsutil sec save command to save the security metadata of a file system.

    For example, save the security metadata of the /acfsmounts/acfs1 file system to the acfs1_backup.xml file.

    $ /sbin/acfsutil sec save –m /acfsmounts/acfs1 
                              –p acfs1_backup.xml
    

    The acfs1_backup.xml security metadata backup file is saved in the /acfsmounts/acfs1/.Security/backup/ directory. The saved XML file can be loaded with the acfsutil sec load command.

You can run some acfsutil sec commands in a batch file with the acfsutil sec batch command. For example, you could create a batch file that contains a group of acfsutil sec rule and acfsutil sec ruleset commands.

Auditing and diagnostic data for Oracle ACFS security is saved to log files.

See Also:

16.1.6 Encrypting Oracle ACFS File Systems

Basic operations to manage encryption on an Oracle ACFS file system on Linux are discussed in this topic.

The examples in this section show a scenario in which the medical history files are encrypted in an Oracle ACFS file system. The steps in this section assume Oracle ACFS security is not configured for the file system; however, you can use both Oracle ACFS security and encryption on the same file system. If you decide to use both security and encryption, then both encryption and security must be initialized for the cluster containing the file system. After security is initialized on the file system, then an Oracle ACFS security administrator runs acfsutil sec commands to provide encryption for the file system.

Because the acfsutil encr set and acfsutil encr rekey -v commands modify the encryption key store, you should back up the Oracle Cluster Registry (OCR) after running these commands to ensure there is an OCR backup that contains all of the volume encryption keys (VEKs) for the file system.

The disk group on which the volume is created for the file system has compatibility attributes for ASM and ADVM set to 11.2.0.3 or higher.

For the examples in this section, various operating system users, operating system groups, and directories must exist.

The basic steps to manage encryption are:

  1. Initialize encryption.

    Run the acfsutil encr init command to initialize encryption and create the storage necessary for the encryption keys. This command must be run one time for each cluster on which encryption is set up.

    For example, the following command initializes encryption for a cluster.

    # /sbin/acfsutil encr init
    

    This command must be run before any other encryption command and requires root or administrator privileges to run.

  2. Set encryption parameters.

    Run the acfsutil encr set command to set the encryption parameters for the entire Oracle ACFS file system.

    For example, the following command sets the AES encryption algorithm and a file key length of 128 for a file system mounted on the /acfsmounts/acfs1 directory.

    # /sbin/acfsutil encr set -a AES -k 128 -m /acfsmounts/acfs1/
    

    The acfsutil encr set command also transparently generates a volume encryption key which is stored in the key store that was previously configured with the acfsutil encr init command.

    This command requires root or administrator privileges to run.

  3. Enable encryption.

    Run the acfsutil encr on command to enable encryption for directories and files.

    For example, the following command enables encryption recursively on all files in the /acfsmounts/acfs1/medicalrecords directory.

    # /sbin/acfsutil encr on -r /acfsmounts/acfs1/medicalrecords
                             -m /acfsmounts/acfs1/
    

    For users that have appropriate permissions to access files in the /acfsmounts/acfs1/medicalrecords directory, they can still read the decrypted files.

    This command can be run by an administrator or the file owner.

  4. Display encryption information.

    Run the acfsutil encr info command to display encryption information for directories and files.

    # /sbin/acfsutil encr info -m /acfsmounts/acfs1/ 
                               -r /acfsmounts/acfs1/medicalrecords
    

    This command can be run by an administrator or the file owner.

Auditing and diagnostic data for Oracle ACFS encryption is saved to log files. .

See Also:

16.1.7 Tagging Oracle ACFS File Systems

The operations to manage tagging on directories and files in an Oracle ACFS file system on Linux are discussed in this topic.

The disk group on which the volume is created for the file system has compatibility attributes for ASM and ADVM set to 11.2.0.3 or higher.

Oracle ACFS implements tagging with Extended Attributes. There are some requirements when using Extended Attributes that should be reviewed.

The steps to manage tagging are:

  1. Specify tag names for directories and files.

    Run the acfsutil tag set command to set tags on directories or files. You can use these tags to specify which objects are replicated.

    For example, add the comedy and drama tags to the files in the subdirectories of the /acfsmounts/repl_data/films directory.

    $ /sbin/acfsutil tag set -r comedy /acfsmounts/repl_data/films/comedies
    
    $ /sbin/acfsutil tag set -r drama /acfsmounts/repl_data/films/dramas
    
    $ /sbin/acfsutil tag set -r drama /acfsmounts/repl_data/films/mysteries
    

    In this example, the drama tag is purposely used twice and that tag is changed in a later step.

    You must have system administrator privileges or be the file owner to run this command.

  2. Display tagging information.

    Run the acfsutil tag info command to display the tag names for directories or files in Oracle ACFS file systems. Files without tags are not be displayed.

    For example, display tagging information for files in the /acfsmounts/repl_data/films directory.

    $ /sbin/acfsutil tag info -r /acfsmounts/repl_data/films
    

    Display tagging information for files with the drama tag in the /acfsmounts/repl_data/films directory.

    $ /sbin/acfsutil tag info -t drama -r /acfsmounts/repl_data/films
    

    You must have system administrator privileges or be the file owner to run this command.

  3. Remove and change tag names if necessary.

    Run the acfsutil tag unset command to remove tags on directories or files. For example, unset the drama tag on the files in the mysteries subdirectory of the /acfsmounts/repl_data/films directory to apply a different tag to the subdirectory.

    $ /sbin/acfsutil tag unset -r drama /acfsmounts/repl_data/films/mysteries
    

    Add the mystery tag to the files in the mysteries subdirectory of the /acfsmounts/repl_data/films directory.

    $ /sbin/acfsutil tag set -r mystery /acfsmounts/repl_data/films/mysteries
    

    You must have system administrator privileges or be the file owner to run these commands.

See Also:

16.1.8 Replicating Oracle ACFS File Systems

The operations to manage Oracle ACFS snapshot-based replication on an Oracle ACFS file system on Linux are discussed in this topic.

The disk groups on which volumes are created for the primary and standby file systems must have compatibility attributes for ASM and ADVM set to 12.2 or higher.

The steps to manage replication are:

  1. Ensure that ssh has been configured for replication.

    • Ensure that host keys and user keys for the ssh command have been configured on your primary and standby clusters.

    • On Windows, ensure that Cygwin is installed and ssh is configured as required for replication.

  2. Ensure that the snapshots needed by replication can be created at all times. At any given point replication, may need to be able to use two concurrent snapshots of the primary file system, and one snapshot of the standby file system.

  3. Ensure that there is adequate network connectivity between the primary and standby sites. You should verify that the achievable network data transfer rate from primary to standby is substantially larger than the rate of change of data on the primary file system.

    One way to estimate network data transfer rate is to start with an observed transfer rate, then reduce it to account for known sources of overhead. For example, you can calculate the elapsed time needed to FTP a 1 G file from the primary file system to the intended standby file system, during a period when network usage is low. This provides an estimate of the maximum achievable transfer rate. This rate should be reduced to account for overheads inherent in replication transfers, as well as to allow for other demands on the network. For replication overhead, a reasonable approach is to reduce the measured rate by 20%, then by an additional 5% for each node in the primary cluster.

    To estimate the average rate of change on the primary, you can use the command acfsutil info fs with the -s option. This command should be run on each node where the primary file system is mounted, and displays that amount and rate of change to the file system on that node. To compute the total rate of change for the file system, the rate of changed for each node must be aggregated. A reasonable value to use for -s is 900, which would yield a 15 minute sampling interval.

    With the output from acfsutil info fs with the -s option, you can determine the average rate of change, the peak rate of change, and how long the peaks last. A conservative approach to using this data is to choose the peak rate of change as the target rate that must be accommodated.

    Because replication must transfer all data changed on the primary to the standby, obviously the achievable network transfer rate must be higher, ideally significantly higher, than the target rate of change on the primary. If this is not the case, you should increase network capacity before implementing replication for this file system and workload.

    For example, assume you have a four node primary cluster and you determine that a 1 G file can be transferred in 30 seconds, yielding a current FTP transfer rate of 33 M per second. An estimate of the current replication transfer rate would be approximately 20 M per second, calculated as follows:

    33 MB/sec * (1 – 0.2 – (4 * 0.05)) = 33 * 0.6 = ~20 MB/sec

    Also, you find that the average rate of change to the primary is 8 GB per hour, with a peak rate of 25 G per hour. Using the peak rate, you can calculate a target rate of change of approximately 7 M per second as follows:

    (25 GB/hour * 1024) / 3600 = ~7 MB/sec

    In the scenario that was discussed in this step, you can reasonably expect the network to be able to handle the additional workload from replication.

  4. Ensure that there is adequate storage capacity on the primary and standby sites.

    Estimate the storage capacity needed for replication on the sites hosting the primary and standby file systems. In the general case, the primary site must store two snapshots of the primary file system on an ongoing basis and the standby site must store a single snapshot of the standby file system. The space occupied by these snapshots mostly consists of user data or metadata preserved in the snapshot, that has since been modified which triggers a new copy of the data to be created.

    The space occupied by replication-related snapshots can be directly viewed using the command acfsutil snap info. On the primary, check for snapshots with the names starting with the string REPL. On the standby, look for snapshots for names starting with SDBACKUP.

    If you use interval-based replication, the -i option to acfsutil repl init primary, and if the replication operations are successfully completing within the specified interval, then the size of replication-related snapshots is related to the rate of change of the primary and the length of the interval. For example, with an average rate of change of 8 G per hour and a two hour replication interval, you would expect that snapshot storage usage is in the range of 16 G per snapshot.

    Snapshot size does vary with the rate of change of the primary. Another factor is that snapshot size depends in part on the number of files in the file system, as well as the rate of change. Potentially more importantly, if you use constant mode replication, the -C option to acfsutil repl init primary, or if replication operations are not completing successfully in the interval given with interval—based replication because the interval is too small, the size of replication-related snapshots is difficult to predict in advance. In these cases, observe the size of the snapshots being generated over time and adjust the file system size as needed with the acfsutil size command to accommodate normal storage needs in addition in the presence of the snapshots. When collecting this information, a good starting point is to accommodate space for the snapshots to contain the data that is multiple times larger than the collection period, at the average rate of change of the primary.

    While collecting this information, choose a conservative starting point for the amount of space to allow for replication snapshots. For example, you can compute the space needed to store changes to the file system over the collection period as described previously, then you can allocate several times that space for future snapshots.

  5. Determine the user to be employed for replication and optionally set up tags.

    Choose or create the replication user who logs in with ssh to the standby cluster to apply data replicated from the primary file system to the standby file system. This user is defined only at the OS level and not within Oracle. The user should belong to the groups defined for Oracle ASM administrator access.

    Optionally set tags on directories and files to replicate only selected files in an Oracle ACFS file system. You can also add tags to files after replication has started.

  6. Configure the site hosting the standby file system.

    Before replicating an Oracle ACFS file system, configure the site hosting the standby file system by performing the following:

    • Create a new standby file system of adequate size to hold the files replicated from the primary file system, as well as a single replication snapshot . For example:

      /standby/repl_data

    • Mount the file system on one node only.

    • Run the acfsutil repl init standby command on the site hosting the standby file system. For example:

      # /sbin/acfsutil repl init standby -u repluser /standby/repl_data

      Note:

      If the acfsutil repl init standby command is interrupted for any reason, the user must re-create the file system, mount it on one node only, and re-run the command.

      This command requires the name of the replication user and the standby file system. The specified user is the user under which ssh, invoked from the primary cluster, logs in to the standby cluster to apply changes. This user is specified with the -u option. For example: -u repluser.

      The mount point is the standby file system. For example: /standby/repl_data.

    • After the acfsutil repl init standby command has successfully completed, mount the specified file system on all nodes of the standby cluster.

    The acfsutil repl init standby command requires root or system administrator privileges to run.

  7. After the standby file system has been set up, configure the site hosting the primary file system and start replication.

    Run the acfsutil repl init primary command on the site hosting the primary file system. For example:

    $ /sbin/acfsutil repl init primary -i 2h -s repluser@standby12_vip -m /standby/repl_data /acfsmounts/repl_data

    This command requires the following configuration information.

    • A replication interval, given with the option -i interval for interval mode or the option -C for constant mode replication. If an interval is specified, the option value is the minimum amount of time that elapses between replication operations. At the start of each operation, replication takes a new snapshot of the primary and compares it to the previous snapshot, if any. The changes needed to update the standby to match the primary are then sent to the standby. If -C is given instead of -i interval, a new replication operation is started as soon as the previous one completes.

      For example, to set up a replication interval of two hours, specify -i 2h.

    • The user name and network endpoint (VIP name or address, or host name or address) to be used to connect to the site hosting the standby file system, specified with the —s option. For example: -s repluser@standby12_vip

    • The mount point of the primary file system. For example: /acfsmounts/repl_data

    • If the mount point is different on the site hosting the standby file system than it is on the site hosting the primary file system, specify the mount point on the standby file system with the -m standby_mount_point option. For example: -m /standby/repl_data

    The acfsutil repl init primary command requires root or system administrator privileges to run.

  8. Monitor information about replication on the file system.

    The acfsutil repl info command displays information about the state of the replication processing on the primary or standby file system.

    For example, you can run the following on the site hosting the primary file system to display configuration information.

    $ /sbin/acfsutil repl info -c -v /acfsmounts/repl_data

    You must have system administrator (the user root on non-Windows systems or local SYSTEM on Windows) or Oracle ASM administrator privileges to run this command.

  9. Manage the replication background process.

    Run the acfsutil repl bg command to start, stop, or retrieve information about the replication background process.

    For example, run the following command to display information about the replication process for the /acfsmounts/repl_data file system.

    $ /sbin/acfsutil repl bg info /acfsmounts/repl_data

    You must have system administrator or Oracle ASM administrator privileges to run the acfsutil repl bg info command.

  10. Pause replication momentarily if necessary.

    Run the acfsutil repl pause to momentarily stop replication. Run the acfsutil repl resume command as soon as possible to resume replication.

    For example, the following command pauses replication on the /acfsmounts/repl_data file system.

    $ /sbin/acfsutil repl pause /acfsmounts/repl_data

    The following command resumes replication on the /acfsmounts/repl_data file system.

    $ /sbin/acfsutil repl resume /acfsmounts/repl_data

    You must have system administrator or Oracle ASM administrator privileges to run the acfsutil repl pause and acfsutil repl resume commands.

  11. Failing over to a standby or turning a standby file system into an active file system.

    If the primary file system is inaccessible, you can run acfsutil repl terminate standby mount_point to turn the standby file system into an active file system. If the primary file system still exists, you should terminate the primary first with acfsutil repl terminate primary mount_point.

    Before terminating replication with acfsutil repl terminate standby on the standby file system, you can determine the point in time of the primary file system that the standby file system represents. This timestamp is displayed with acfsutil repl info -c as Last sync time with primary. If the failover action must be coordinated with Oracle Data Guard, you can use the timestamp to set back the database if needed, or perform other necessary actions that are based on the timestamp.

    The standby file system may be in the process of being modified by replication. This could occur if:

    • The primary file system is available and a replication operation is currently in progress.

    • The primary file system is not available, but a replication operation was in progress when it became unavailable.

    To be sure of obtaining the contents of the standby file system when it was last identical to a snapshot from the primary, follow one of these procedures.

    • If the primary file system is available, run the acfsutil repl terminate primary command on the primary site to terminate replication. The command waits for any in-progress replication operation to complete before it returns. Then run acfsutil repl info -c to determine the point in time of the primary file system represented on the standby. After you have this information, run acfsutil repl terminate standby on the standby site.

    • If the primary file system is not available, you should first compare two date strings from the acfsutil repl info -c output; these are the dates from the Receiving primary as of line and the Last sync time with primary line. If these dates are identical, then the standby file system contains the most recent available point-in-time image of the primary. If they are not equal, you must use the backup snapshot recorded by replication to recover the last point-in-time image captured on the standby. You can find this snapshot using the acfsutil snap info command. Search for a snapshot with a name of the form:

      SDBACKUP_tstamp1_REPL_tstamp2

      where tstamp1 represents the time at which the backup snapshot was created, and tstamp2 represents the point in time when the primary contents in this snapshot were recorded. There should be only one backup snapshot present. The date of the backup snapshot corresponds to the date in the Last sync time with primary line output by acfsutil repl info -c. If there is no backup snapshot available, then the contents of the primary were never successfully transferred to the standby.

      The date of the backup snapshot corresponds to the date in the Last sync time with primary line output by acfsutil repl info -c.

      To use the backup snapshot, you must terminate replication and ensure that the snapshot is preserved because it is deleted by default. To ensure the snapshot is preserved, add the -k option to the command line for acfsutil repl terminate standby. After replication has been terminated, you can run the acfsutil snap remaster command to use the snapshot as the new contents of the standby file system.

Note:

When replication is in use, replication snapshots can be viewed using the acfsutil snap info command, just as any other snapshot can. You can use this command to get an approximate idea of the space currently occupied by replication snapshots.

See Also:

16.1.9 Deregistering, Dismounting, and Disabling Volumes and Oracle ACFS File Systems

This section discusses the operations to deregister or dismount a file system and disable a volume. This section contains these topics:

16.1.9.1 Deregistering an Oracle ACFS File System

You can deregister an Oracle ACFS file system if you do not want the file system to be automatically mounted.

For example:

$ /sbin/acfsutil registry -d /acfsmounts/acfs1

If you deregister a file system, then you must explicitly mount the file system after Oracle Clusterware or the system is restarted.

For more information about the registry, see "About the Oracle ACFS Mount Registry". For information about acfsutil registry, see "acfsutil registry".

16.1.9.2 Dismounting an Oracle ACFS File System

You can dismount a file system without deregistering the file system or disabling the volume on which the file system is mounted.

For example, you can dismount a file system and run fsck to check the file system.

# /bin/umount /acfsmounts/acfs1

# /sbin/fsck -a -v -y -t acfs /dev/asm/volume1-123

After you dismount a file system, you must explicitly mount the file system.

Use umount on Linux systems or acfsdismount on Windows systems. For information about the commands to dismount a file system, see "umount" or "acfsdismount".

Use fsck on Linux systems or acfschkdsk on Windows systems to check a file system. For information about the commands to check a file system, see "fsck" or "acfschkdsk".

16.1.9.3 Disabling a Volume

To disable a volume, you must first dismount the file system on which the volume is mounted.

For example:

# /bin/umount /acfsmounts/acfs1

After a file system is dismounted, you can disable the volume and remove the volume device file.

For example:

ASMCMD> voldisable -G data volume1

Dismounting the file system and disabling a volume does not destroy data in the file system. You can enable the volume and mount the file system to access the existing data. For information about voldisable and volenable, see Managing Oracle ADVM with ASMCMD .

16.1.10 Removing an Oracle ACFS File System and a Volume

You can remove an Oracle ACFS file system and volume with acfsutil and ASMCMD commands.

To permanently remove a volume and Oracle ACFS file system, perform the following steps. These steps destroy the data in the file system.

  1. Deregister the file system with acfsutil registry -d.

    For example:

    $ /sbin/acfsutil registry -d /acfsmounts/acfs1
    acfsutil registry: successfully removed ACFS mount point
       /acfsmounts/acfs1 from Oracle Registry
    
  2. Dismount the file system.

    For example:

    # /bin/umount /acfsmounts/acfs1
    

    You must dismount the file system on all nodes of a cluster.

    Use umount on Linux systems or acfsdismount on Windows systems.

  3. Remove the file system with acfsutil rmfs.

    If you were not planning to remove the volume in a later step, this step is necessary to remove the file system. Otherwise, the file system is removed when the volume is deleted.

    For example:

    $ /sbin/acfsutil rmfs /dev/asm/volume1-123
    
  4. Optionally you can disable the volume with the ASMCMD voldisable command.

    For example:

    ASMCMD> voldisable -G data volume1
    
  5. Delete the volume with the ASMCMD voldelete command.

    For example:

    ASMCMD> voldelete -G data volume1
    

See Also: