Life cycle of a tape in the data center
New tapes must be registered and initialized before they are used in the local data center for the first time.
The tape administrator enters the new tapes in the catalog of existing tapes. This catalog can be implemented and managed using different means. The software product MAREN (MAREN catalog) is recommended for the purpose of automation. The new tapes are, for example, initialized with the BS2000 utility routine INIT. The operator needs to know which new tapes are available. Only then can the operator process tape requests for these tapes.
As soon as an application has written data to a tape, the operator may not mount this tape for any other application unless he/she has been authorized to do so by the tape owner. A tape used by an application is reserved until the application (i.e. the application user, in other words the tape owner) decides that it is no longer required. The criterion of ownership is the user ID under which the application was started. When the tape is released, the user must inform the tape administrator of the fact that it may now be used by other applications again.
A tape can be released again automatically if the user agrees that the tape administrator may use the tape again after a defined period of time has elapsed.
Once a tape has been released and can be used again by other applications, data protection measures require any data still contained on the tape to be deleted or to be protected against access by the next application, so the tape has to be reinitialized.
Without the use of MAREN, the tape administrator has to inform the operator of the current status of the tapes available for tape requests:
- the tape can be reallocated to an application (new or released);
- the tape may only be used by the application it is already allocated to;
- the tape may be used by the application it is already allocated to or by other applications.
Tapes in different BS2000 systems
How tapes are distributed to different BS2000 systems depends on the way a data center is organized. Here are some options:
- The BS2000 systems are assigned unambiguously to departments (or customers), and the resources are separated from each other;
- The BS2000 systems are allocated to different customers of the data center, depending on the current load. Their resources are shared.
The tapes can be administered as follows:
- in a common pool for all BS2000 systems;
- separately according to BS2000 systems;
- separately according to customer.
In this case it is recommendable to use lists with information specifying the system on which the tape is located.
The tapes available for new reservations are contained in a free tape pool. Tapes reserved by an application are allocated to the user ID under which the application was started. Tape organization can be graded even more finely by reserving a range of archive numbers for a specific user group or some other criterion (e.g. job name, file name).
Some free tape pools can be reserved for standard applications of the BS2000 system (e.g. HSMS/ARCHIVE). MAREN can manage the pools of other system programs.
Example of how to organize tapes
The free tapes are all in a common free tape pool and are available for all users on all BS2000 systems.
System 1 System 2 USER1 USER2 USER3 USER1 USER3 USER4 Reserved Free common free tape pool The free tapes are allocated to individual pools for specific users or user groups on each BS2000 system. The users can only reserve tapes from the pool allocated to them.
System 1 System 2 USER1 USER2 USER3 USER1 USER3 USER4 Reserved only in pool1 only in pool2 only in pool3 only in pool4 only in pool5 Free pool1 common pool2 pool3 pool4 pool5 The tapes and BS2000 systems of various data center customers are grouped to form domains, and each user can only work within his/her domain.
Domain_1 Domain_2 System 1 System 2 System 3 System 4 USER1 USER2 USER2 USER3 USER4 USER5 Reserved Free common pool
The tape administrator has to distribute the available resources according to the requirements of the customers. MAREN allow the utilization of tapes to be administered and monitored according to specific requirements.
The regulations concerning the release of tapes (expiration date, retention period) can be defined by the tape administrator and modified on the request of the users. These regulations define, among other things, how a tape’s transition from the “reserved” status to the free tape pool is to be effected.
Beside a tape’s utilization, the tape administrator must make sure that the data on the tape is retained for the duration of its reservation. The data protection is extended by legal regulations that require data to be retained for a period of time.
The life cycle of the recordings may be lower than the prescribed retention period. In this case the data has to be “refreshed”, i.e. it either has to be rewritten or copied to another tape.
Another problem that the tape administrator must keep in mind is the useful life of a tape. If a tape is used frequently, faults may occur that reduce the quality of data recordings. Read errors or sequence errors as well as errors during mounting (load check) will occur more frequently. The tape administrator has to keep an eye on the frequency with which a tape is used and, if necessary, copy its contents to a new tape and throw out the old one.
Location of the tapes
In order to support the operator in searching for specific tapes in a large data center, the tape administrator must record where the tapes are located. This information is referred to as the location of the tapes. Each location is identified by the attributes name, usage type (manual / automatic), site (local / remote).
Tape devices are also assigned to locations, which are referred to as device depots. The device depots are defined and managed in BS2000 (ADD-DEVICE-DEPOT command).
Tapes used on manually operated tape devices should be assigned to a special location in the vicinity of such tape devices, so the operator can find them quickly when they need to be mounted. The location of the tape devices (the device depot) must have the same name as the location for the tapes defined in MAREN.
In particular when archive systems are used, the tape devices used in an archive system must be assigned to the same location as the tapes of the archive system. This also applies for the virtual tapes in virtual archive systems (e.g. ETERNUS CS).
Applications can explicitly request tapes to be stored at particular locations. Locations can also be assigned to an application by means of the utility routine MARENLM or using MAREN exits.
Removal of tapes
Tapes contained in a loading system are not automatically allocated to the location defined for the device. The tape administrator can change the location allocated to such tapes, if necessary, in order to make this temporary situation known to the applications using the location.
Tapes that are used for archiving or backup purposes are kept in a secure room (e.g. a fireproof room) which forms a location of its own. This room is represented by a separate location, and the volumes contained there are either recorded manually by the tape administrator or by MAREN.
The tape administrator has to record the removal of tapes from one location to another according to his own method.
Tapes can either be moved from one location to another within the same data center or they can be sent to another data center (foreign data center).
Both types of relocation can either be recorded manually or automatically by MAREN. In the case of automatic recording, MAREN must request the operator to perform relocation or transport. This request is realized by console messages and the output of special forms. The operator confirms the relocation (which is then his/her responsibility), and at the same time MAREN records the change of location.
