Using the UNIX Backup-Archive Clients


Using Storage Management Policies

Storage management policies are rules that your ADSM policy administrator defines to tell ADSM how to manage backups and archives, based on the needs of users and the business. If you have the ADSM HSM client installed, your administrator also defines rules that determine whether files are eligible for migration from your local file systems to ADSM storage.

For backup and archive, policies determine:

This section first explains more about storage management policies. Then, it shows you how to display what policies are available to you. Next, you can read about how to choose the best policies for your files and directories. And finally, this section explains some concepts about how ADSM associates your data with policies.

Understanding Storage Management Policies

Storage management policies have several components, as described by the following terms:

Copy group
The specific storage management attributes that describe how the server is to manage backed up or archived data. There are two kinds of copy groups: backup copy groups and archive copy groups

Management class
A collection of backup and archive copy groups that establishes similar storage management requirements for backing up and archiving data.

If you have the ADSM HSM client installed, a management class can also contain space management attributes that determine whether files are eligible for migration and where they are stored. For information about space management attributes, see Using the UNIX HSM Clients

Most of the work you do with storage management policies is with management classes.

Policy set
A group of one or more management classes. The ADSM administrator uses a policy set to implement different management classes based on business and user needs.

Policy domain
A group of clients that have similar needs for backup and archive. Policy domains contain one or more policy sets.

Understanding Policy Domains and Sets

An ADSM administrator uses policy domains to manage a group of client nodes in a logical way. For example, a domain could consist of the following clients:

ADSM includes a policy domain named STANDARD. Initially, your client node is probably associated with that policy domain. However, your ADSM administrator can define additional policy domains if there are groups of users that have unique backup and archive requirements.

Each policy domain can hold numerous policy sets. Only one of these policy sets can be active at a time, called the active policy set. Each policy set contains a default management class and any number of additional management classes.

Understanding Management Classes and Copy Groups

A management class contains the specific requirements for backing up and archiving data. If you have the ADSM HSM client installed, it can also contain specific requirements for migrating files to ADSM storage.

An ADSM administrator can establish separate management classes to meet the backup and archive requirements for different kinds of data, such as:

Each file and directory that you back up and each file that you archive must be associated with a management class. You are responsible for associating files and directories with appropriate management classes. If you do not associate a file with a management class, ADSM uses the default management class in the active policy set. If you do not specify a management class for directories, ADSM uses the management class in the active policy set that specifies the longest retention period.

You associate files with management classes by using INCLUDE options in your include-exclude options file. See "Choosing a Management Class for Files" for more information. To associate directories with a management class, you use the DIRMC option in your client system options file. See "Choosing a Management Class for Directories" for more information.

Within a management class, the specific backup and archive requirements are in copy groups. There are two kinds of copy groups: backup copy groups and archive copy groups. A management class can have one backup copy group, one archive copy group, both, or neither.

Backup Copy Groups

A backup copy group contains attributes that ADSM uses during the backup process to determine the following:

It also contains attributes that ADSM uses to manage the backup versions of your files on the server. Those attributes control the following:

Archive Copy Groups

An archive copy group contains attributes that control the following:

Displaying Information About Management Classes

Before you choose the management classes you want to use, you need to see which ones are available by clicking on the Utilities menu; Display policy information item. The information is displayed in the Display Policy Information window.

You can also use the QUERY MGMTCLASS command with the DETAIL option to see the available management classes.

Policy Information

ADSM displays the following information in this window:

For policy information, you see this information:

Default Management Class
The name of the default management class for this policy set.

Policy Domain
The name of the policy domain to which this management class belongs.

Active Policy Set
The policy set that is active at the time.

Activation Date
The date and time that this policy set became the active one.

Grace Period Backup Retain
The number of days to retain a backup version when the server is unable to rebind the file to an appropriate management class.

Grace Period Archive Retain
The number of days to retain an archived copy when the server is unable to rebind the file to an appropriate management class.

For more information on grace periods, see "Using a Retention Grace Period".

Management Class Information

For management class information, you see this information:

Management Class Name
The name of the management class.

Description
A description of the management class.

If you have the ADSM HSM client installed, the management class information can also include:

Space Management Technique
Determines whether a file can be migrated automatically and selectively, selectively only, or neither.

Auto Migrate on Non-Usage
The number of days that must elapse since a file was last accessed before it is eligible for automatic migration.

Backup Required Before Migration
Determines whether a backup version of a file must exist before the file is eligible for migration.
Attention

If this attribute is set to Yes, ADSM checks for a backup version only on your migration server. If your backup-archive server and migration server are not the same, setting this option to Yes prohibits migration.

Destination for Migrated Files
The name of the destination where ADSM stores migrated files. The destination can be either a storage pool of disk devices or a storage pool of devices that support removable media such as tape.

Copy Groups

You will see information for both backup and archive copy groups:

Copy Group Name
For backup and archive copy groups, the copy group name is always STANDARD.

Copy Type
For backup copy groups, the type is always BACKUP. For archive copy groups, the type is always ARCHIVE.

Copy Frequency
For backup copy groups, the minimum number of days that must elapse between successive incremental backups.

Copy frequency works with the copy mode parameter that is described later. For example, if copy frequency is 0, and copy mode is modified, a file or directory is backed up only if it has been changed since the last incremental backup.

If copy frequency is 0, and copy mode is absolute, a file is backed up every time you run an incremental backup against it.

ADSM does not check this attribute for selective backups.

For archive copy groups, the copy frequency is always CMD (command), that is, there is no restriction on how often you can archive a file.

Versions Data Exists
For backup copy groups, the maximum number of different backup versions ADSM retains for files and directories currently in your file system.

If you select a management class that allows more than one backup version, the most current version is called the active version. All other versions are called inactive versions.

If the maximum number of versions allowed is 5, and you run a backup that creates a sixth version, ADSM deletes the oldest version from server storage.

Versions Data Deleted
For backup copy groups, the maximum number of different backup versions ADSM retains for files and directories that you have erased from your file system. ADSM ignores this parameter as long as the file or directory remains in your file system.

If you erase the file or directory, the next time you run an incremental backup, ADSM changes the active backup version to inactive and erases the oldest versions that are in excess of the number specified by this parameter.

The expiration date for the remaining versions is based on the Retain Extra Versions and Retain Only Version parameters described later.

Retain Extra Versions
For backup copy groups, how many days ADSM retains all but the most recent backup version. The most recent version is the active version, and active versions are never erased.

If Nolimit is specified, extra backup versions are deleted based on the Versions Data Exists or Versions Data Deleted parameters.

Retain Only Version
For backup copy groups, how many days ADSM retains the last remaining inactive version of a file or directory.

If Nolimit is specified, the last version is retained forever.

Retain Version
For archive copy groups, the number of days an archived file remains in ADSM storage.

When the specified number of days elapse for an archived copy of a file, ADSM deletes it from ADSM storage.

Copy Serialization
For backup and archive copy groups, whether a file can be in use during a backup or archive, and what to do if it is. The value for this parameter can be one of the following:

Static
A file or directory must not be modified during backup or archive. If the object is changed during the backup or archive attempt, it is not backed up or archived.

Shared Static
A file or directory must not be modified during backup or archive. ADSM attempts to perform a backup or archive as many as four additional times, depending on the value specified for the CHANGINGRETRIES option in your client system options file. If the object is changed during every backup or archive attempt, it is not backed up or archived.

Dynamic
A file or directory is backed up or archived on the first attempt regardless of whether it changes during backup or archive.

Shared Dynamic
A file or directory is backed up or archived regardless of whether it changes during backup or archive. However, ADSM tries as many as four additional times, depending on the value specified for the CHANGINGRETRIES option in your client system options file, to back up or archive the file without the file changing during the attempt. The file is backed up or archived on the last try even if it has changed.

Attention

Be careful about choosing a management class that contains a copy group that specifies shared dynamic or dynamic for copy serialization.

If you choose a management class that allows a file to be backed up or archived while it is in use, the backup or archive stored on the server might be a fuzzy copy. A fuzzy copy is a backup or archive that does not accurately reflect what is currently in the file. It might contain some, but not all, of the changes. If that is not acceptable, be sure to choose a management class that allows ADSM to create a backup or archive only if the file does not change during backup or archive.

If you restore or retrieve a file that contains a fuzzy copy, the file might not be usable, depending on the file's application.

Copy Mode
For backup copy groups, this attribute determines whether a file or directory is considered for incremental backup only if it has changed since the last backup or regardless of whether it has changed. ADSM does not check the copy mode for selective backups. The value for this parameter can be one of the following:

Modified
Indicates the file is considered for incremental backup only if it has changed since the last backup. A file is considered changed if any of the following are different:
The date or time of the last modification
The file size
The file owner
The file permissions

Absolute
Indicates the file is considered for incremental backup regardless of whether it has changed since the last backup.

For archive copy groups, the copy mode is always absolute, which indicates that a file is archived regardless of whether it has changed since the last archive request.

Copy Destination
For backup and archive copy groups, the name of the destination where ADSMstores the backup or archive. The destination can be either a storage pool of disk devices or a storage pool of devices that support removable media such as tape.

Default Values for Management Class STANDARD

ADSM includes a default management class named STANDARD. Figure 3 shows the default values for the backup and archive copy groups in this management class.

Figure 3. Default Values in the STANDARD Management Class
Attribute Backup Default Archive Default
Copy Group Name STANDARD STANDARD
Copy Type BACKUP ARCHIVE
Copy Frequency 0 days CMD
Versions Data Exists 2 versions N/A
Versions Data Deleted 1 version N/A
Retain Extra Versions 30 days N/A
Retain Only Version 60 days N/A
Retain Version N/A 365 days
Copy Serialization shared static shared static
Copy Mode modified absolute
Copy Destination BACKUPPOOL ARCHIVEPOOL

Figure 4 shows the default values for space management attributes in the STANDARD management class if you have the ADSM HSM client installed.

Figure 4. Default Values for Space Management Attributes
Attribute Default
Space Management Technique None
Auto Migrate on Non-Usage 0
Backup Required Before Migration Yes
Destination for Migrated Files SPACEMGPOOL

Choosing a Management Class for Files

If the default management class meets the backup, archive, and space management requirements for all the files on your workstation, you do not need to take any action to associate your files with that management class. ADSM does that automatically when your files are backed up, archived, or migrated.

Using an Include-Exclude Options File to Assign a Management Class

To assign a management class other than the default to a file or group of files, use an INCLUDE statement in your include-exclude options file. For example, to associate all the files in the /home/jones/costs directory with a management class named BUDGET use the following include statement:

   INCLUDE /home/jones/costs/* budget

Management class names are not case sensitive.

To specify a management class to be used for all files to which you do not explicitly assign a management class, use the following include statement as the first statement in your include-exclude options file:

   INCLUDE * managall

where managall is the name of an available management class. For more information about using the include-exclude options file, see "Using Management Classes with the Include Option".

Overriding the Management Class for Archived Files

When you archive a file, you can choose to override the assigned management class. When using the graphical user interface, ADSM presents a window that allows you to select a different management class.

When using the ARCHIVE command, you can use the ARCHMC option to specify a different management class. For example, to associate the file /home/jones/budget.jan with the management class RET2YRS, you specify the following:

   dsmc archive -archmc=ret2yrs /home/jones/budget.jan

For more information about ARCHMC, see Archive.

Questions to Consider When Choosing a Management Class

If you need to choose a different management class for some of your files, consider the following questions.

Note:If you have the ADSM HSM client installed, and you want a file to be eligible for migration, you must assign the file a management class that also contains the appropriate space management attributes.

Choosing a Management Class for Directories

If the management class in your active policy set that contains the longest retention period meets your backup requirements for directories, you do not need to take any action to associate directories with that management class. ADSM does it automatically when it backs up your directories.

If that default management class does not meet your requirements, be sure to choose a management class with an adequate retention period specified for Retain Only Version. You want to be sure that ADSM keeps directories at least as long as it keeps the files associated with those directories.

To assign a management class other than the default to directories, you use the DIRMC option in your client system options file. For example, to assign a management class named DIRECT1 to your directories, you would enter:

   DIRMC DIRECT1

For more information about using DIRMC, see Dirmc.

Binding and Rebinding Management Classes to Files

When you back up a file for the first time, ADSM binds it to either the default management class or the management class specified for the file in your include-exclude options file. Binding is the term for associating a file with a management class.

If the backup copy group for the management class instructs ADSM to keep multiple backup versions of the file, and you request multiple backups, the server always has one active backup version (the most current version) and one or more inactive backup versions of the file. All the backup versions of a file are bound to the same management class and are managed based on the attributes in the backup copy group.

When you archive a file, ADSM binds it to the default management class, to the management class specified for the file in your include-exclude options file, or to a management class you specify.

There are several instances when backup versions of a file can be rebound to a different management class. Archived files are never rebound to a different management class. If you change the management class for a file, any previous copies of the file that you have archived remain bound to the management class specified when you archived them.

Rebinding Backup Versions of Files

Backups of files are rebound to a different management class in the following cases. In each case, the files (active and inactive) are not rebound until the next backup.

Using a Retention Grace Period

ADSM also provides a backup retention grace period and an archive retention grace period that it uses to help protect your backup and archive data when it is unable to rebind a file to an appropriate management class.

For example, ADSM uses the backup retention grace period in these cases:

ADSM begins using the backup retention grace period when you run an incremental backup.

The backup retention grace period is defined in your policy domain. The default is 30 days. However, your ADSM administrator can choose to change that value to a longer or shorter period.

After ADSM begins managing a file using the backup retention grace period, it does not create any new backup versions of the file. All existing backup versions of the file expire 30 days (or the number of days specified in your policy domain) from the day they are marked inactive.

For archived files, if the management class to which a file is bound no longer exists, and the default management class does not contain an archive copy group, ADSM uses the archive retention grace period defined in your policy domain. The default retention period is 60 days. Your ADSM administrator can choose to change that value to a longer or shorter period.


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