UPDATE DEVCLASS (Update a GENERICTAPE device class)

When this device type is used, the server does not recognize either the type of device or the cartridge recording format. Because the server does not recognize the type of device, if an I/O error occurs, error information is less detailed compared to error information for a specific device type (for example, 8MM). When you define devices to the server, do not mix various types of devices within the same device type.

Privilege class

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

Parameters

device_class_name (Required)

Specifies the name of the device class to be updated.

LIBRary

Specifies the name of the defined library object that contains the tape drives used by this device class. This parameter is optional. For information about defining a library object, see the DEFINE LIBRARY command.

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.

Specify a capacity appropriate to the particular tape drive that is being used.

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="".

MOUNTRetention

Specifies the number of 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 MOUNTLIMIT value (including online status).

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 that are used concurrently in this device class 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.