Know more on problems and requirements related to removable media management

Know more on  problems and requirements related to removable media management

The problems and requirements relating to the integration of removable media in the storage network can be divided into two areas:

1. the management of removable media; and

2. the sharing of the associated resources.

In large environments, removable media management must be able to catalogue hundreds of thousands of media, storing not only the media and their attributes, but also accessing these media with corresponding data about errors, duration of use, etc. In contrast to hard disk storage, it is possible to store the media separately from drives, which means that the system must additionally know the location of a medium at all

times. Since this location can be a manually-managed store or an automatic library in which the cassettes are automatically located, special solutions are required that take these requirements into account. The second important field of application for a removable media management system

in the storage network is the sharing of libraries, drives and media. This sharing between several applications connected to the storage network requires corresponding mechanisms for access control, access synchronization and access prioritization. These mechanisms control who may access which hardware when, so that potentially all applications can access all resources available in the storage network. In order to be able to fulfil these requirements, there is an increasing need for management layers for removable media in storage networks. These layers link existing

applications to the hardware connected via the storage network (Figure 9.3). They control and synchronize all accesses and should remain as transparent as possible to the applications. As a central interface, this middleware should therefore be capable of managing all resources and also the sharing, i.e. the sharing of libraries, drives and cartridges by various applications. We already discussed in Section 6.2.2 the various options for realizing library and drive sharing for removable media in storage networks. As also mentioned at that point, we believe that an architecture that shields the applications from the complex internal processes during management and sharing represents the best and most promising solution.

After all, the management is familiar with all components and their interaction. Therefore, an optimal control over the use of resources can also be implemented there. Individually, the following problems and requirements can be defined:

• Resource Utilization: Efficient use of all available resources by intelligent sharing.

• Access control: Applications and users must be authenticated. Applications and users may only be given access to the media for which suitable authorization exists.

• Access synchronization: Accesses to libraries and drives must be synchronized. • Access prioritization:

Prioritization can be used if several accesses to a resource, for example a drive, are to

be performed.

• Media tracking: It must be guaranteed at all times that every medium can be found and accessed.

• Grouping, pooling: It should be possible to dynamically aggregate both media and drives into groups or pools in order to simplify management and sharing.

• Monitoring: Automatic monitoring of the system.

• Reporting: Accesses to media must be logged. Audit trails should be possible.

• Life cycle management: Media run through a life cycle. They are written, read, written again and after a certain time taken out of circulation.

• Vaulting: Management of offline storage locations.

In what follows we investigate the above-mentioned problems and requirements further.