If you are defining a device class
for devices that are to be accessed through a z/OS® media
server,
see UPDATE DEVCLASS (Update a 3592 device class for z/OS media server).
Privilege class
To issue this command, you must have system privilege or unrestricted storage privilege.
Syntax
>>-UPDate DEVclass--device_class_name---------------------------> >--+--------------------------+---------------------------------> '-LIBRary--=--library_name-' >--+-----------------------------+------------------------------> '-LBProtect--=--+-READWrite-+-' +-WRITEOnly-+ '-No--------' >--+---------------------------+--+------------------------+----> '-SCALECAPacity--=--+-100-+-' '-FORMAT--=--+-DRIVE---+-' +-90--+ +-3592----+ '-20--' +-3592C---+ +-3592-2--+ +-3592-2C-+ +-3592-3--+ +-3592-3C-+ +-3592-4--+ '-3592-4C-' >--+----------------------+-------------------------------------> '-ESTCAPacity--=--size-' >--+-----------------------------------+------------------------> '-PREFIX--=--+-ADSM---------------+-' '-tape_volume_prefix-' >--+----------------------------+--+-----------------------+----> '-MOUNTRetention--=--minutes-' '-MOUNTWait--=--minutes-' >--+---------------------------+--------------------------------> '-MOUNTLimit--=--+-DRIVES-+-' +-number-+ '-0------' >--+----------------------------------------------+------------>< | (1) (2) | '-------------DRIVEEncryption--=--+-ON-------+-' +-ALLOW----+ +-EXTERNAL-+ '-OFF------'
- You cannot specify both WORM=Yes and DRIVEENCRYPTION=ON.
- Drive encryption is supported only for 3592 Generation 2 or later drives.
Parameters
- device_class_name (Required)
- Specifies the name of the device class to be updated. The maximum length of the device class name is 30 characters.
- LIBRary
- Specifies the name of the defined library object that contains the tape drives that can be used by this device class. For information about defining a library object, see the DEFINE LIBRARY command.
- LBProtect
Specifies whether logical block protection is used to ensure the integrity of data stored on tape. When LBPROTECT is set to READWRITE or to WRITEONLY, the server uses this feature of the tape drive for logical block protection and generates cyclic redundancy check (CRC) protection information for each data block written on tape. The server also validates the CRC protection information when data is read from the tape.
The following values are possible:- READWrite
- Specifies that logical block protection is enabled in the server
and the tape drive for both read and write operations. Data is stored
with CRC information in each block. This mode affects performance
because additional processor usage is required for Tivoli® Storage
Manager and the
tape drive to calculate and compare CRC values. The READWRITE value
does not affect backup sets and data that is generated by the BACKUP
DB command.
When the LBPROTECT parameter is set to READWRITE, you do not have to specify the CRCDATA parameter in a storage pool definition because logical block protection provides better protection against data corruption.
- WRITEOnly
- Specifies that logical block protection is enabled in the server and the tape drive for write operations only. Data is stored containing CRC information in each block. For read operations, the server and the tape drive do not validate the CRC. This mode affects performance because additional processor usage is required for Tivoli Storage Manager to generate the CRC and for the tape drive to calculate and compare CRC values for write operations. The WRITEONLY value does not affect backup sets and data that are generated by the BACKUP DB command.
- No
- Specifies that logical block protection is not enabled in the server and the tape drive for read and write operations. However, the server enables logical block protection on write operations for a filling volume that already has data with logical block protection.
Restriction: Logical block protection is supported only on IBM® 3592 Generation 3 drives and later with 3592 Generation 2 media and later.See Technote 1634851, Additional information on the Tivoli Storage Manager LBProtect option, for an explanation about when to use the Tivoli Storage Manager LBProtect parameter.
- SCALECAPacity
- Specifies the percentage of the media capacity that can be used
to store data. This parameter is optional. Possible values are 20,
90, or 100.
Setting the scale capacity percentage to 100 provides maximum storage capacity. Setting it to 20 provides fastest access time.
Note: The scale capacity value takes effect when data is first written to a volume. Any updates to the device class for scale capacity do not affect volumes that already have data that is written to them until the volume is returned to scratch status. - FORMAT
- Specifies the recording format to be used when date is written
to sequential access media. This parameter is optional.
If the drives are in a library that includes drives of different tape technology, do not use the DRIVE value. Use the specific format that the drives use.
The following table lists the recording formats, estimated capacities, and recording format options for 3592 devices:Table 1. Recording formats and default estimated capacities for 3592 Format Estimated Capacity Description DRIVE – The server selects the highest format that is supported by the drive on which a volume is mounted. Attention: Avoid specifying DRIVE when a mixture of drives is used within the same library. For example, do not use this option for a library that contains some drives that support recording formats superior to other drives.3592 300 GB Uncompressed (basic) format 3592C See note
900 GB
Compressed format 3592-2 500 GB 700 GB
Uncompressed (basic) format JA tapes Uncompressed (basic) format JB tapes
3592-2C 1.5 TB 2.1 TB
Compressed format JA tapes Compressed format JB tapes
3592–3 640 GB 1 TB
Uncompressed (basic) format JA tapes Uncompressed (basic) format JB tapes
3592–3C 1.9 TB 3 TB
Compressed format JA tapes Compressed format JB tapes
3592-4 400 GB 1.5 TB
3.1 TB
Uncompressed (basic) format JK tapes Uncompressed (basic) format JB tapes
Uncompressed (basic) format JC tape
3592-4C 1.2 TB 4.4 TB
9.4 TB
Compressed format JK tapes Compressed format JB tapes
Compressed format JC tapes
Note: If this format uses the tape-drive hardware-compression feature, depending on the effectiveness of compression, the actual capacity might be different from the listed value.Important: For optimal performance, avoid mixing different generations of drives in a single SCSI library. If you must mix drive generations in a SCSI library, use one of the special configurations that are described in the Administrator's Guide to prevent or minimize media problems.Special configurations are also required for mixing different generations of 3592 drives in 349x and ACSLS libraries. For details, see the Administrator's Guide.
- ESTCAPacity
- Specifies the estimated capacity for the volumes that are assigned
to this device class. This parameter is optional.
You can specify this parameter if the default estimated capacity for the device class is inaccurate due to compression of data.
You must specify this value as an integer followed by K (kilobytes), M (megabytes), G (gigabytes), or T (terabytes). For example, ESTCAPACITY=5M specifies that the estimated capacity for a volume in this device class is 5 MB.
The smallest value that is allowed is 1 MB (that is, ESTCAPACITY=1M). To force the IBM Tivoli Storage Manager server to determine the estimated capacity for the volumes that are assigned to this device class, specify ESTCAPACITY="".
- PREFIX
- Specifies the high-level qualifier of the data set name that the
server writes into the sequential access media labels. For each sequential
access volume assigned to this device class, the server uses this
prefix to create the data set name. This parameter is optional. The
maximum length of this prefix is 8 characters.
If you previously established a media label naming convention that supports your current management system, use a volume prefix that conforms to your naming conventions.
An example of a tape volume data set name that uses the default prefix is ADSM.BFS.
- MOUNTRetention
- Specifies the amount of time, in minutes, to retain an idle sequential
access volume before dismounting it. This parameter is optional. You
can specify a number from 0 to 9999.
This parameter can improve response time for sequential access media mounts by leaving previously mounted volumes online. However, for EXTERNAL library types, setting this parameter to a low value (for example, two minutes) enhances device sharing between applications.
- MOUNTWait
- Specifies the maximum number of minutes the server waits for an operator to respond to a request to either mount a volume in a drive in a manual library or check in a volume to be mounted in an automated library. This parameter is optional. If the mount request is not satisfied within the specified amount of time, the mount request is canceled. You can specify a number from 0 to 9999.
- MOUNTLimit
- Specifies the maximum number of sequential access volumes that
can be simultaneously mounted for the device class. This parameter
is optional. You can specify a number from 0 to 4096.
If you plan to use the simultaneous-write function, ensure that sufficient drives are available for the write operation. If the number of drives needed for a simultaneous-write operation is greater than the value of the MOUNTLIMIT parameter for a device class, the transaction fails.
The following are possible values:- DRIVES
- Specifies that every time a mount point is allocated, the number
of drives that are defined to the library is used to calculate the
true value (including online status).Note: For EXTERNAL library types, do not use the DRIVES default for the MOUNTLIMIT value. Specify the number of drives for the library as the MOUNTLIMIT value.
- number
- Specifies the maximum number of drives that are used concurrently in this device class by the server. This value must never be allowed to exceed the number of drives that are defined and online in the library that services this device class.
- 0 (zero)
- Specifies that no new transactions can gain access to the storage pool.
- DRIVEEncryption
- Specifies
whether drive encryption is allowed. This parameter is optional.
Updating this parameter affects empty volumes only. If a filling volume was previously encrypted or is unencrypted, and you update the DRIVEENCRYPTION parameter, the volume maintains its original encrypted or unencrypted status. The filling volume also maintains its original key-management status.
- ON
- Specifies that Tivoli Storage Manager is the key manager for drive encryption and allows drive encryption for empty storage pool volumes only if the application method is enabled. (Other types of volumes-for example, back up sets, export volumes, and database backup volumes-will not be encrypted.) If you specify ON and you enable either the library or system method of encryption, drive encryption is not allowed and backup operations fail.
- ALLOW
- Specifies that Tivoli Storage Manager does not manage the keys for drive encryption. However, drive encryption for empty volumes is allowed if either the library or system method of encryption is enabled.
- EXTERNAL
- Specifies that Tivoli Storage Manager does not manage the keys for drive encryption. Use this setting with an encryption methodology that is provided by another vendor and that is used with Application Method Encryption (AME) enabled on the drive. When you specify EXTERNAL and Tivoli Storage Manager detects that AME encryption is enabled, Tivoli Storage Manager does not turn off encryption. By contrast, when you specify ALLOW and Tivoli Storage Manager detects that AME encryption is enabled, Tivoli Storage Manager turns off encryption.
- OFF
- Specifies that drive encryption is not allowed. If you enable either the library or system method of encryption, backups fail. If you enable the application method, Tivoli Storage Manager disables encryption and backups are attempted.