Create data class

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Use this page to create a data class construct for use in the IBM® TS7700 Grid.

Note: The user interface of the Data Classes table within the page changes when all clusters in the GRID operate at microcode level 8.54.0.x or later.
To create a new data class:
  1. From the Data Classes page, go to the Data Classes table.
  2. Click Create Data Class in the top-left tab of the Data Classes table. You will see a wizard window.
  3. Complete the required fields: Name, Virtual Volume Size, and Description.
  4. Click Next to select Compression Properties for Compression Method and 3490 Counters Handling.
  5. Click Next to select LWORM Properties.
  6. Click Next to see the settings summary.
  7. Click Finish to finalize the Data Class creation, or click Cancel to halt the operation.
    Note: You can create up to 256 data classes per IBM TS7700 Grid.
However, to create a Data Class when the clusters in the GRID operate at microcode levels prior to 8.54.0.x you must do the following:
  1. From the Data Classes page, navigate to the Data Classes table.
  2. Select Add... from the Select Action drop-down menu.
  3. Click Go to open the Add Data Class page.
Enter values for the following fields:
Name
The name of the data class. The value in this field must be 1 - 8 characters in length. Each data class within a cluster or cluster pair must have a unique name. Valid characters for this field are:
A-Z, 0-9, $, @, and #
The first character of this field cannot be a number. This field is the only field that cannot be modified when added.
Description
A description of the data class definition. The value in this field must be at least 0 and no greater than 70 characters in length.

Use the menu on the Data Classes table to add a data class, modify, copy, or delete an existing data class.

Logical WORM
Whether Logical WORM (write-once, read-many), or LWORM, is set for the data class. Logical WORM is the virtual equivalent of WORM tape media, achieved through software emulation.

Yes, with retention

Logical WORM is set for the data class. Volumes belonging to the data class are defined as logical WORM with retention.

Yes, without retention

Logical WORM is set for data class without retention. Volumes belonging to the data class are defined as logical WORM but without retention.

No

Logical WORM is not set. Volumes belonging to the data class are not defined as logical WORM. This value is the default for a new data class.

Note: However, when it is a mix GRID, and clusters in the grid operate at microcode level prior to 8.54.0.x, the menu shows the following values to enable logical WORM:
Possible values are:

Yes

Logical WORM is set for the data class. Volumes belonging to the data class are defined as logical WORM.

No

Logical WORM is not set. Volumes belonging to the data class are not defined as logical WORM. This value is the default for a new data class.

Compression Method
  • FICON Compression - compression that is performed by the hardware (FICON adapters).
  • LZ4 Compression - software compression that uses an LZ4 algorithm. This compression method is faster and uses less CPU than the ZSTD method but it gives a lower compression ratio than ZSTD.
  • ZSTD Compression - software compression that uses a Zstandard algorithm. This compression method gives a higher compression ratio than LZ4 but is slower and uses more CPU than LZ4.
3490 Counters Handling
  • Surface EOT - Set this option to surface EOT when channel bytes written reach maximum channel byte counter (68 GB).
  • Wrap Supported - Set this option to allow channel bytes written to exceed maximum counter value and present the counter overflow unit attention, which will then collect and reset the counters.
Virtual Volume Size (MiB)
The virtual volume size of the data class; it determines the maximum number of MiB for each virtual volume in a defined class.
Note: Refer to the topic Data storage values in the Related Information section for additional information concerning the use of binary prefixes.
With microcode levels 8.31.0.x and later, virtual volume sizes can be determined either by device bytes or channel bytes. Device bytes are post-compression bytes that travel through the virtual and physical tape system. Channel bytes are uncompressed bytes that travel through the FICON network. For more information, see Virtual volume tape format in the Related information section. If the cluster is a TS7720 or TS7740, virtual volume sizes are determined by device bytes.
Possible values include:
Insert Media Class
Virtual volume size is not defined; the data class is not defined by a maximum virtual volume size.
1000 MiB
2000 MiB
4000 MiB
6000 MiB
25000 MiB
65000 MiB
Note: A 25000 MiB maximum is available without restrictions when all clusters in the grid operate at microcode level 8.32.0.x or later. Otherwise, these restrictions apply:
  1. In a mixed grid (where at least one cluster operates at microcode level 8.32.0.x or later and at least one cluster operates at an earlier microcode level) the following conditions apply:
    • FC 0001 must be installed on every cluster operating at a microcode level earlier than 8.32.0.x.
    • When the grid contains a tape-attached cluster (either a TS7760 Tape Attach or a TS7770 Tape Attach), FC 0001 must be installed on every cluster operating at a microcode level earlier than 8.32.0.x before those clusters are joined to the tape-attached cluster.
    • When the grid contains a cluster that is attached to a tape library, the 25000 MiB options are visible from the management interface in the clusters that operate at microcode level 8.32.0.x or later. The 25000 MiB options are not visible from the management interface in the clusters that operate at earlier microcode levels.
Note: A 65000 MiB maximum is available when all clusters in the grid operate at microcode level 8.54.0.x or later.
Note: These restrictions apply to 25000/65000 MiB virtual volumes:
  1. By default, the TS7700 Grid allows up to 128 simultaneous host I/O jobs running with more than 25000 MiB virtual volumes. This number of host I/O jobs that are allowed in the Grid is adjustable by using a host command line request..
  2. Depending on the Grid network performance and the number of copy tasks for more than 25000 MiB volumes, consider increasing the volume copy timeout time from the default value of 180 minutes to 240 minutes if the copies are timing out. This can be done by using the TS7700 Management Interface or by using a Library Request Command.

LWORM retention options

LWORM retention options can be set when LWORM is set to Yes, with retention.

  • Retention Type (HDR1/Fixed): The setting to determine whether a fixed duration or the contents of HDR1 records should be used to calculate and apply the LWORM retention date.

  • Retention Settings: The LWORM retention settings of the data class.

    • Fixed duration: A duration to calculate the LWORM retention date when any LWORM retention setting mentions using this value. You can select Days, Forever, or None.
    • Fixed duration days: This option is available only when you selectDays to Fixed duration. The unit is "day" and - from 1 to 2928000 days can be set. 0 means that no retention date adjustment is required.
    • Allow early return to scratch:The setting to allow a logical volume to return to scratch when the volume is in a private category and LWORM retention date is not expired yet.
    • Use fixed duration for expire hold: The setting to make LWORM retention date adjustment using a fixed duration if a logical volume is returned to scratch successfully. (If Fixed duration is None, N/A is provided, and you cannot select any other option).

  • HDR1 Options: The HDR1 options are available when the HDR1 retention type is selected.

    Note: Any applied or honored option is ignored if the option's calculated retention date would be sooner than the volume's current retention date.
    • Application managed duration: A duration to calculate the LWORM retention date when the expiration date in HDR1 record is an application managed date and any LWORM retention setting mentions to use this value. You can select Days, Forever, or None.
    • Application managed duration days: If Application managed duration is set to None or Forever, this option is not available. The unit is "day" and - from 1 to 2928000 days can be set when Application managed duration is set to Days. 0 means that no retention date adjustment is required . This is null when "retentionType" is "FIXED"
    • Apply "Fixed Duration" if the first written HDR1 contains no valid date: The setting to use "fixedDuration" when first IBM standard label HDR1 has "no date" expiration date. This option is N/A when Fixed Duration is set to None.
    • Apply "Fixed Duration" at demount time after at least one write occurred and no HDR1 exists on the entire tape: The setting to use "fixedDuration" when data is written to a logical volume from BOT but no IBM standard label HDR1 is written before demount occurs. This is null when "retentionType" is "FIXED" or "fixedDuration" is 0.
    • Honor additional HDR1 records after a first HDR1 has been written: The setting to honor 2nd+ IBM standard label HDR1 expiration date if two or more IBM standard label HDR1 records are written.
    • Honor "Application Managed Duration" for additional HDR1 records containing an application managed date: The setting to use "applicationManagedDuration" if 2nd+ IBM standard label HDR1 is written during the first mount or all subsequent mounts, which have "application managed date". This is N/A when Application managed duration is None or Honor subsequent HDR1 records for appended filesets is No.
    • Apply "Fixed Duration" when additional HDR1 records contain no valid date: The setting to use "fixedDuration" if 2nd+ IBM standard label HDR1 is written during the first mount or all subsequent mounts, which have "no date" expiration date. This option is N/A when Fixed Duration is set to None.
    • Use "Fixed Duration" if a subsequent mount with append occurs with no additional HDR1: The setting to use "fixedDuration" if a private mount with data append occurs and no IBM standard label HDR1 is written during the private mount. This option is N/A when Fixed Duration is set to None.
Note: The Tape Volume Cache Preference field is only available if the cluster possesses a physical library.

To complete the operation click OK. To abandon the operation and return to the Data Classes page, click Cancel.