IBM Tivoli Storage Manager, Version 7.1

UPDATE DEVCLASS (Update 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.

Privilege class

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

Syntax


>>-UPDate DEVclass--device_class_name--------------------------->

>--+--------------------------+--+-----------------------+------>
   '-LIBRary--=--library_name-'  '-FORMAT--=--+-DRIVE--+-'   
                                              +-9840---+     
                                              '-9840-C-'     

>--+----------------------+------------------------------------->
   '-ESTCAPacity--=--size-'   

>--+-----------------------------------+------------------------>
   '-PREFIX--=--+-ADSM---------------+-'   
                '-tape_volume_prefix-'     

>--+----------------------------+--+-----------------------+---->
   '-MOUNTRetention--=--minutes-'  '-MOUNTWait--=--minutes-'   

>--+---------------------------+-------------------------------><
   '-MOUNTLimit--=--+-DRIVES-+-'   
                    +-number-+     
                    '-0------'

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 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. For more information about the VolSafe device type, see DEFINE DEVCLASS (Define a VOLSAFE device class).

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.

Attention: 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 tapes
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	80 GB	LZ-1 Enhanced (4:1) compressed format, using an 80 GB cartridge with 270 meters (885 feet) of tape

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="".

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

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.

If you already established a tape label naming convention that supports your current tape management system, consider the use of a tape volume prefix that conforms to your naming conventions.

MOUNTRetention

Specifies the number of minutes to retain an idle sequential access volume before dismounting it. This parameter is optional. The default value is 60. 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 (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.

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 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. The default is DRIVES. 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.

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