DEFINE DEVCLASS (Define a REMOVABLEFILE device class)

Use the REMOVABLEFILE device class for removable media devices that are attached as local, removable file systems.

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--=--REMOVABLEfile---------->

   .-MAXCAPacity--=--space_remaining-.   
>--+---------------------------------+-------------------------->
   '-MAXCAPacity--=--size------------'   

   .-MOUNTRetention--=--60------.  .-MOUNTWait--=--60------.   
>--+----------------------------+--+-----------------------+---->
   '-MOUNTRetention--=--minutes-'  '-MOUNTWait--=--minutes-'   

   .-MOUNTLimit--=--DRIVES-----.   
>--+---------------------------+-------------------------------><
   '-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 removable media drives used by this device class. For information about defining a library object, see the DEFINE LIBRARY command.

DEVType=REMOVABLEfile (Required)

Specifies that the REMOVABLEFILE device type is assigned to the device class. REMOVABLEFILE indicates that the volumes for this device class are files on local, removable media.

Volumes in a device class with device type REMOVABLEFILE are sequential access volumes.

Use the device manufacturer's utilities to format (if necessary) and label the media. The label on the media must meet the following restrictions:

The label can have no more than 11 characters.
The volume label and the name of the file on the volume must match exactly.
The MAXCAPACITY parameter value must be specified at less than the capacity of the media.

MAXCAPacity

Specifies the maximum size of any volumes that are defined to a storage pool categorized by this device class. This parameter is optional.

The MAXCAPACITY parameter must be set at less value than the capacity of the media. For CD media, the maximum capacity can be no greater than 650 MB.

AIX operating systems HP-UX operating systems Oracle Solaris operating systems Windows operating systems Because the server opens only one file per physical removable medium, specify a capacity that enables one file to make full use of your media capacity.

space_remaining: The default maximum capacity is the space that remains on the media after it is first used.
size: You must specify this value as an integer followed by K (kilobytes), M (megabytes), G (gigabytes), or T (terabytes).

For example, MAXCAPACITY=5M specifies that the maximum capacity for a volume in this device class is 5 MB. The smallest value that is allowed is 1 MB (that is, MAXCAPACITY=1M).

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.

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.

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.