How to use Efficient use of the available resources and Access Control

How to use  Efficient use of the available resources and Access Control

A great advantage of the use of well-designed storage networks is the fact that the available hardware resources are better utilized. In contrast to directly connected devices, the available storage space is available to many applications and can therefore be used significantly more effectively. In the field of removable media this is achieved by the better utilization of the free storage capacity and the sharing of drives. Efficient use of the storage capacity The disk storage pooling described in Section 6.2.1 is transferable to removable media one-to-one. In this case, free storage space should be taken to mean both unused removable media and also free slots for removable media, which must be kept in reserve due to the continuous growth in data. Ideally, this takes place in a cross-library manner. To this end, all free cartridges from all libraries are managed in a so-called scratch pool (Section 9.4.6), which is available to all applications, so that the remaining free storage capacity can be flexibly assigned.

Efficient use of the drives What applies for the effective use of the free storage capacity also applies in the same way for the use of the drives. If drives are directly connected to servers they cannot be used by other servers, even if they currently have no cartridge loaded into them.

By contrast, drives in storage networks can be assigned to the applications that need them at the time. Thus, it can be ensured that all drives that are installed are also actually used. The utilization of drives can be further increased by mount request queuing. However, more time is then required to perform the mount requests in the queue. This is a typical time-versus-space optimization problem. With more drives, more mount requests can be

carried out in the same time. If, however, a lot of mount requests are not urgent, fewer drives can execute the requests one after the other. Ideally, the mount requests in the queues are prioritizable, so that urgent tasks are actually performed sooner.

 Access control

Reliable control to prevent unauthorized access to media is indispensable. Users and  applications must be authenticated. Successfully authenticated users can then be given suitable authorization to access certain resources. Authentication Users, and also applications, that want to make use of removable media management services must be registered with the system. A sufficiently strict authentication mechanism should ensure that only users and applications that have been unambiguously identified can use the system. Authorization Authorization is necessary to prevent unauthorized users from being able to view, or even change, data belonging to other users. Authorization can both apply for certain operations and also arrange access to certain objects (cartridges, partitions, volumes, drives, etc.). A successful authentication is a necessary prerequisite for authorization.

By means of an appropriate authorization, users or applications can be assigned the following rights regarding certain objects in the management system:

• generation and deleting of objects (e.g. the allocation and deallocation of volumes);

• read access to objects (e.g. read access to own volumes);

• write access to objects (e.g. addition of cartridges to a scratch pool);

• mount and unmount of cartridges, sides, partitions or volumes;

• moving of cartridges within libraries;

• import and export of cartridges;

• activation and deactivation of libraries or drives.

The use of various authorization levels allows access control to be modified according to the user's role. The following roles and activities are currently used in systems for the list serves as an example only. These roles and activities can also be assigned differently

depending upon the specific requirements.

The system administrator is responsible for:

• installation of the system

• installation/deinstallation of libraries

• user and application management

• management of disk and cartridge groups.

The storage administrator is responsible for:

• management of disk and cartridge groups

• cartridge life cycle management

• planning of the future requirements for resources.

The library administrator is responsible for:

• management of disk and cartridge groups for individual libraries

• planning of the future requirements for resources

• starting and continuance of the operation of individual libraries

• starting and continuance of the operation of individual drives.

The library operator is responsible for:

• starting and continuance of the operation of individual libraries

• monitoring the operation of libraries

• starting and continuance of the operation of individual drives

• monitoring of the operation of drives in the libraries

• manual import and export of cartridges into and out of libraries

• performance of mount/unmount operations in manually operated libraries

• moving cartridges within a library.The users/applications may:

• allocate and de-allocate volumes to cartridges

• mount and unmount volumes

• read and write volumes

• list and display volumes that they have allocated

• list and display cartridges upon which volumes they have allocated have been put

• list and display scratch cartridges, which are included in cartridge groups to which there is an access right

• list and display drives that are included in drive groups to which there is an access right.