Archival Storage

TIB operates its own Computer Centre, which is administered by its internal IT department.

Two independent file servers are available for the archival storage; these are operated as RAID 6 systems. The file servers are positioned in separate, locked server racks at the Computer Centre. Objects are stored redundantly with their metadata; the data is mirrored weekly at a set time. Storage capacity is scalable.

The server racks are equipped with temperature monitoring and a gas fire extinguishing system for each shelf. Each file server has a reporting tool that enables storage capacity, the condition of the hard disks and tasks such as data mirroring to be monitored manually. In the event of a hard disk breakdown or defect, the file server automatically triggers an alert to the administrator.

TIB has a service agreement with a service provider covering the replacement of defective hardware.

Data integrity is ensured using Fletcher4 checksums. One checksum is generated and saved for each block. A checksum is generated at every read access, and compared to the checksum saved. If the checksums do not match, the defective block will be recovered from the RAID 6 system. The redundant copies on the mirror are used for disaster recovery. Checksums ensure the consistency of redundant copies on the mirror.

TIB plans to extend the Computer Centre and to further develop its backup (see Backup Plan).

Access to the Computer Centre is secured by an electronic access system and a burglar alarm system, and is restricted to just a few members of staff. The Computer Centre is equipped with a fire and smoke detection system as well as an independent emergency power supply that ensures continued operation for around one day in the event of a power cut.

Access to the file servers can only be gained if the individual has the corresponding rights and logon information.

Objects are not submitted to the archival storage directly; they are initially saved on a separate deposit server. Only authorised members of staff can transfer objects to the archive server. Changes to objects are documented in the metadata, and the objects are versioned.