DEFINE DEVCLASS (Define a VOLSAFE device class)

Use the VOLSAFE device type to work with StorageTek VolSafe brand media and drives. This technology uses media that cannot be overwritten. Therefore, do not use these media for short-term backups of client files, the server database, or export tapes.

Restrictions:

NAS-attached libraries are not supported.
VolSafe media and read/write media must be in separate storage pools.
Check in cartridges with CHECKLABEL=YES on the CHECKIN LIBVOLUME command.
Label cartridges with OVERWRITE=NO on the LABEL LIBVOLUME command. If VolSafe cartridges are labeled more than one time, no additional data can be written to them.

Privilege class

To issue this command, you must have system privilege or unrestricted storage privilege.

Syntax


>>-DEFine DEVclass--device_class_name--------------------------->

>--LIBRary--=--library_name--DEVType--=--VOLSAFE---------------->

                 .-FORMAT--=--DRIVE---------.   
>--WORM--=--Yes--+--------------------------+------------------->
                 '-FORMAT--=--+-DRIVE-----+-'   
                              +-9840------+     
                              +-9840-C----+     
                              +-T9840C----+     
                              +-T9840C-C--+     
                              +-T9840D----+     
                              +-T9840D-C--+     
                              +-T10000A---+     
                              +-T10000A-C-+     
                              +-T10000B---+     
                              +-T10000B-C-+     
                              +-T10000C---+     
                              +-T10000C-C-+     
                              +-T10000D---+     
                              '-T10000D-C-'     

                             .-MOUNTRetention--=--60------.   
>--+----------------------+--+----------------------------+----->
   '-ESTCAPacity--=--size-'  '-MOUNTRetention--=--minutes-'   

   .-PREFIX--=--ADSM--------------.   
>--+------------------------------+----------------------------->
   '-PREFIX--=--+-ADSM----------+-'   
                '-volume_prefix-'     

   .-MOUNTWait--=--60------.  .-MOUNTLimit--=--DRIVES-----.   
>--+-----------------------+--+---------------------------+----><
   '-MOUNTWait--=--minutes-'  '-MOUNTLimit--=--+-DRIVES-+-'   
                                               +-number-+     
                                               '-0------'

Parameters

device_class_name (Required)

Specifies the name of the device class to be defined. The maximum length of the device class name is 30 characters.

LIBRary (Required)

Specifies the name of the defined library object that contains the VolSafe drives that can be used by this device class. If any drives in a library are VolSafe-enabled, all drives in the library must be VolSafe-enabled. Consult your hardware documentation to enable VolSafe on the 9840 and T10000 drives.

For information about defining a library object, see DEFINE LIBRARY (Define a library).

DEVType=VOLSAFE (Required)

Specifies that the VOLSAFE device type is assigned to the device class. The label on this type of cartridge can be overwritten one time, which Tivoli® Storage Manager does when it writes the first block of data. Therefore, it is important to limit the use of the LABEL LIBVOLUME command to one time per volume by using the OVERWRITE=NO parameter.

WORM

Specifies whether the drives use WORM (write once, read many) media. The parameter is required. The value must be Yes.

Yes: Specifies that the drives use WORM media.

FORMAT

Specifies the recording format to be used when data is written to sequential access media. This parameter is optional. The default value is DRIVE.

Important: If you specify DRIVE for a device class that has non-compatible sequential access devices, then you must mount volumes on devices that are capable of reading or writing the format that is established when the volume was first mounted. This can cause delays if the only sequential access device that can access the volume is already in use.

The following table lists the recording formats and estimated capacities for VolSafe devices:

Table 1. Recording formats and default estimated capacities for Volsafe media
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.
9840	20 GB	Uncompressed (standard) format, using a 20 GB cartridge with 270 meters (885 feet) of tape
9840-C	See note 80 GB	LZ-1 Enhanced (4:1) compressed format, using an 80 GB cartridge with 270 meters (885 feet) of tape
T9840C	40 GB	Uncompressed T9840C format, using a StorageTek 9840 cartridge
T9840C-C	80 GB	Compressed T9840C format, using a StorageTek 9840 cartridge
T9840D	75 GB	Uncompressed T9840D format, using a StorageTek 9840 cartridge
T9840D-C	150 GB	Compressed T9840D format, using a StorageTek 9840 cartridge
T10000A	500 GB	Uncompressed T10000A format, using a StorageTek T10000 cartridge
T10000A-C	1 TB	Compressed T10000A format, using a StorageTek T10000 cartridge
T10000B	1 TB	Uncompressed T10000B format, using an Oracle StorageTek T10000 cartridge
T10000B-C	2 TB	Compressed T10000B format, using an Oracle StorageTek T10000 cartridge
T10000C	5 TB	Uncompressed T10000C format, using an Oracle StorageTek T10000 T2 cartridge
T10000C-C	10 TB	Compressed T10000C format, using an Oracle StorageTek T10000 T2 cartridge
T10000D	8 TB	Uncompressed T10000D format, using an Oracle StorageTek T10000 T2 cartridge
T10000D-C	15 TB	Compressed T10000D format, using an Oracle StorageTek T10000 T2 cartridge

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 one of the following unit indicators: K (kilobytes), M (megabytes), G (gigabytes), or T (terabytes). The smallest value that is accepted is 1 MB (ESTCAPACITY=1M).

For example, specify that the estimated capacity is 9 GB with the parameter ESTCAPACITY=9G.

For more information about the default estimated capacity for cartridge tapes, see Table 1.

MOUNTRetention

Specifies the number of minutes that an idle sequential access volume is retained before it is dismounted. This parameter is optional. The default value is 60 minutes. You can specify a number 0 - 9999.

This parameter can improve response time for sequential access media mounts by leaving previously mounted volumes online.

However, for EXTERNAL library types (that is, a library that is managed by an external media management system), set this parameter to a low value (for example, two minutes) to enhance device sharing between applications.

Note: For environments in which devices are shared across storage applications, the MOUNTRETENTION setting must be carefully considered. This parameter determines how long an idle volume remains in a drive. Some media managers do not dismount an allocated drive to satisfy pending requests. You might need to tune this parameter to satisfy competing mount requests while maintaining optimal system performance. Typically, problems arise more frequently when the MOUNTRETENTION parameter is set to a value that is too small, for example, zero.

PREFIX

Specifies the beginning portion of the high-level archive file name on the target server. This parameter is optional. The default is ADSM. The maximum length of this prefix is 8 characters.

If you have a naming convention for media labels to support your current management system, use a volume prefix that conforms to your naming conventions.

Values that are specified for this parameter must meet the following conditions:

The value is to be made up of qualifiers, which can be a maximum of eight characters including periods. For example, the following value is acceptable:
```
     AB.CD2.E
```
The qualifiers must be separated by a single period.
The first letter of each qualifier must be alphabetic or national (@,#,$), followed by alphabetic, national, hyphen, or numeric characters.

An example of a high-level archive file name that uses the default prefix is ADSM.volume1.

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. The default value is 60 minutes. You can specify a number 0 - 9999.

MOUNTLimit

Specifies the maximum number of sequential access volumes that can be simultaneously mounted for the device class. This parameter is optional. The default is DRIVES. You can specify a number 0 - 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 and online in the library is used to calculate the true value.; Note: For EXTERNAL library types, do not specify DRIVES for the MOUNTLIMIT value. Specify the number of drives for the library as the MOUNTLIMIT value.
number: Specifies the maximum number of drives in this device class that are used concurrently by the server. This value must never 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. Any current transactions continue and complete, but new transactions are terminated.