Tutors on Monitoring management of removable media

Tutors on Monitoring management of removable media

The large number of devices and media that have to be monitored in a data centre makes it almost impossible for monitoring to be performed exclusively by administrators. Automatic control of the system, or at least of parts of it, is therefore absolutely necessary for installations above a certain size. For removable media, in particular, it is important that monitoring is well constructed because in daily operation there is too little time to verify every back-up. If errors creep in whilst the system is writing to tape this may not be recognized until the data needs to be restored – when it is too late. If there is no second copy, the worst conceivable incident for the datacenter has occurred: data loss! Modern tape drives permit a very good monitoring of their state. This means that the number of read-write errors that cannot be rectified by the built-in firmware, and also the

number of load operations, are stored in the drive. Ideally, this data will be read by the management system and stored so that it is available for further evaluations. A further step would be to have this data automatically analyzed by the system. If certain error states are reached, actions can be triggered automatically so that at least no further error states are permitted. Under certain circumstances, errors can even be rectified automatically, for example by switching a drive off and back on again. In the worst case, it is only possible to mark the drive as defective so that it is not used further. In these tasks, too, a mechanism controlled by means of rules can help and significantly take the pressure off the administrator.

The data stored on the drives not only provides information on the drives themselves, but also on the loaded tapes. This data can be used to realize a tape quality management, which, for example, monitors the error rates when reading and writing and, if necessary, copies the data to a new tape if a certain threshold is exceeded.

Reporting

In addition to media management and drive and library sharing a powerful system requires the recording of all actions. For certain services it is even a legal requirement that so-called security audits are performed. Therefore, all actions must be precisely logged. In addition, he log data must be protected against manipulation in an appropriate manner. With the aid of a powerful interface, it should be possible to request data including

the following:

• When was a cartridge incorporated into the system?

• Who allocated which volume to which cartridge when?

• Who accessed which volume when?

• Was this volume just read or also written?

• Which drive was used?

• Was this an authorized access or was access refused? The following requirements should be fulfilled by the reporting module of a removable

media management system:

• Audit trails As already mentioned, it should be possible to obtain a complete list of all accesses to

a medium. Individual entries in this list should give information about who accessed a

medium, for how long, and with what access rights.

• Usage statistics Data about when the drives were used, and for how long they were used, is important

in order to make qualitative statements about the actual utilization of all drives. At

any point in time, were sufficient drives available to carry out all mount requests? Are

more drives available than the maximum amount needed at the same time over the last

twelve months? The answers to such questions can be found in the report data. Like

the utilization of the drives, the available storage space is, of course, also of interest.

Was enough free capacity available? Were there bottlenecks?

• Error statistics Just like the data on the use of resources, data regarding the errors that occurred during use is also of great importance for the successful use of removable media. Have the storage media of manufacturer X caused less read-write errors in the drives of manufacturer Y than the media of manufacturer Z? Appropriate evaluations help considerably in the optimization of the overall performance of a system.

• Future planning  Predictions for the future can be made from the above-mentioned statistics. How will the need for storage grow? How many drives will be used in twelve months? And  MANAGEMENT OF REMOVABLE MEDIA how many slots and cartridges? A management system should be able to help in the search for answers to these questions. In order that future changes can also be simply carried out, the addition of further drives or cartridges must also be possible without any problems and must not require any changes to the existing applications that use the management services.