Product Code Database
An optical jukebox is a robotic data storage device that can automatically load and unload from drives, such as Compact Disc, DVD, Blu-ray, or UDO to provide (TB) or (PB) of tertiary storage. Such systems are also called optical disk libraries, optical storage archives, robotic drives, disc changers, or autochangers. Jukeboxes can fit hundreds of discs in a desktop or 5Rack unit carousel box or thousands in a full-rack cabinet, and usually have a picking device that traverses the slots and drives. Arrangement of the slots and picking devices affects performance and maintenance costs, depending on the robotics design, the space between a disk and the picking device, and number of drives. Seek times and transfer rates vary depending upon the drive used.
Similar systems exist using other media, such as the magnetic cassette-based tape library.
Jukeboxes are used in high-capacity archive storage environments such data centers and on-premise server rooms to store long-term data such as imaging, medical, compliance records, video and other high-value data assets, objects, and files. Hierarchical storage management is a strategy that moves little-used or unused files from fast magnetic storage to optical jukebox devices in a process called migration. If the files are needed, they are migrated back to magnetic disk. Optical disc libraries are also useful for making and in IT disaster recovery situations. Today one of the most important uses for jukeboxes is to archive data. Archival is different from backup in that the data is stored on media designed to last up to 100 years. The data is usually permanently written on Write Once Read Many (WORM)-type discs to prevent tampering.
Jukeboxes typically contain internal SCSI or SATA-based recordable drives (CD-R/RW, DVD-RAM, DVD±R/RW, MO, PD, UDO or BD-R/RE) that connect directly to a file server and are managed by a third-party jukebox management software. This software controls the movement of media within the jukebox, and the pre-mastering of data prior to the recording process.
Before the advent of the modern RAID SAN and much cheaper , high-volume storage on DVD was cheaper than magnetic disks. Jukebox densities have greatly increased with the release of the 128 gigabyte (GB) Blu-ray XL quadruple layer (BDXL QL) format, with a road-map to increase to eight layers and 200 GB per disc. The current format, used in a single 700-disc jukebox such as the DISC ArXtor7000 library, allows 89 TB of storage. Other jukeboxes like the TeraStack Solution can store up to 142 TB of online and nearline data with a nominal power draw of 425 , while the Zerras ICEBOX allows up to 25TB in a single unit library with a power draw of 60 watts per unit and scaling to 200TB in a 42U rack cluster. These units show the wide variance of design attributes. Such jukeboxes using bare commercial off-the-shelf Blu-ray discs differ from proprietary solutions such as Sony's Optical Disc Archive libraries, which use proprietary Archival Discs sealed in multi-disc cartridges incompatible with Blu-Ray drives and discs from the consumer market.
Filesystem types available for optical media range from ISO standard technologies like UDF to proprietary formats.
Another way that access to the optical library may be accomplished is by way of CIFS shares (more often seen with Unix-type optical library management applications).
Small jukeboxes have only one or two CD, DVD, or Blu-ray drives, so users requesting simultaneous access to files on only one or two discs can share the jukebox at the same time. If additional users want to use a different disc, they have to wait for the disc to be swapped by the robots in the jukebox and the drive to spindown/spinup. This takes from 4 to 9 seconds. Larger jukeboxes have six or more drives, so more users can simultaneously access different discs at the same time.
A more efficient option is to have an HDD or SSD cache attached to the jukebox for a higher number of simultaneous users. This way, the configuration operates in a FILO (First In Last Out) manner, so files changed are only sent back to the optical discs after they have been used. Changes may or may not be saved or versioned based on the user configuration and accessibility settings on the storage management software that runs the optical jukebox. The drives will read and write the data to the RAID / disc cache and then present it to end users. This way the read time only occurs during the initial data read process, then the data is sent to the cache.
|
|
