In a data storage system that employs multiple storage drives to access removable data storage media, idle data storage media are analyzed and than selectively demounted by automated equipment to increase storage drive availability and also minimize unnecessary mount/demount operations. Initially, the system establishes a maximum permitted number of concurrently mounted idle storage media, and also establishes a maximum permitted length of time for leaving idle storage media mounted. Next, storage media mounted to the media drives are analyzed for possible demounting. The system determines how many storage media are presently mounted, and each media's mount time. Then, the system identifies suitable demounting candidates (if any) to comply with the established maximums. Namely, the system identifies the media with the greatest idle times whose demounting is necessary to both (1) reduce the number of concurrent mounts down to the maximum permitted number, and (2) demount any storage media with idle times exceeding the maximum permitted length of time..
An apparatus capable of determining state of a device comprises a controller and a monitor executable on the controller. The monitor is capable of passively monitoring traffic between an initiator and the device, determining when the passively monitored traffic is insufficient for identifying state of the device, and actively issuing supplemental commands to the device to refresh device information when passively monitored traffic is insufficient. The monitor can also determine device state from the device information.
In a data storage system with multiple output media types, each request to store a data object is automatically analyzed to select the optimal output media type. In choosing the output media type best suited to quickly and efficiently complete the storage requests, the storage system considers (1) attributes of the data object itself, such as its size, (2) any perceived urgency required to complete the data storage request, and (3) attributes of the system's storage devices, such as the availability of different output media types, presence of other storage requests queued for storage for each type, level of ongoing access of each storage type by concurrent storage tasks, delays to initiate storage such as mount/demount times, amount of storage space available in different output media types, and the like.
