Hierarchical Storage Maagement -Introduction -Applications -Structure -Uses

1. Hierarchical Storage
Management
Developed By : Jaydeep Patel(13MCA63)
Kuldeep Patel(13MCA64)

2. Definition…
• HSM is data storage technique, which automatically moves data
between high-cost and low-cost storage media.
• Mass storage-Multimedia Objects
• An application may actually use different types of media for
different purposes .This approach is called hierarchical
management

3. continue…..The primary goal of hierarchical storage is to route data to the
lowest cost devices that will support the required performance for
that object.

4. A multimedia application requires storage for
following functions:
• Disk cache or system memory cache
• Hard disk cache
• High speed disk storage
• Optical media and optical disc libraries
• Magnetic or optical tapes

5. Permanent vs. Transient storage issues
• Optical disk is used for permanent storage .They are
considered a much safer storage than other.
• During life of multimedia object, it may be reside on one
or all of the storage hierarchies.
• The process of moving data from one level of storage
hierarchy to another is called migration.
• Migration of this objects to off-line media from on-line
media is called archiving.
• Migration can be set up to be manual or automatic.

6. • In document imaging systems, compressed image
files are created in magnetic cache areas on fast
storage devices when documents are scanned.
• On completion of indexing and quality check they
are moved to another magnetic storage area used
for images accessed recently.

7. Optical Disk Library(Jukebox)
o An optical jukebox is a robotic data storage device that can
automatically load and unload optical discs, such as Compact
Disc, DVD, Ultra Density Optical or Blu-ray disc and can
provide terabytes (TB) and petabytes (PB) of storage.
o The devices are often called optical disk libraries, robotic drives,
or auto-changers.

8. o Jukebox can contain one or more drives.
o The drives are daisy-chained on SCSI bus with their own SCSI Ids. The robotics device
also behaves as a SCSI device with its own SCSI ID thereby allowing programmatic
control of the device.
o The size of jukeboxes varies from small desktop versions for the large from factors to
full 19’’ rack versions(at least two racks are required) for the large from factors.
o A jukebox stack can carry 50-200 optical disks. With storage capacity of a single disk
as high as 1 to 10 Gbytes, a jukebox cam store several terabytes of data.

9. How Jukebox Used?
o Jukebox is used for storing large volumes of multimedia information in
one cost effective store.
o Jukebox-based optical disk libraries can be networked so that multiple
users can access the information.
o For example it can be used as a document image server for all
departmental documents.

10. Optical Disk Library Performance
o The best-case performance is achieved when the required information is in an optical
disk which is already mounted in a drive.

11. Optical Disk Library continue…
o The worst-case performance is when the required information is on a
platter(disk volume) which is not mounted in a drive, and all drives have
other mounted disk volumes.
o The disk access and transfer time are so small compared to the disk fetch
and insertion time.

12. Hierarchical Storage Applications
1. Banks
2. Insurance Companies
3. Hospitals
4. State and Federal governments
5. Manufacturing companies
6. variety of other business and service organizations
Need to permanently store large volumes of their records, from simple documents to
video information, for audit trail use.
o The WORM optical disks provide the most cost effective media that is almost on-line.

13. Best Examples of Multimedia Applications
o Police records with fingerprints and mug-shots require multimedia
applications.
o Insurance companies can photograph or prepare video clips of vehicles
and accident scenes and store them on optical disks.
o City and country governments use optical storage for maintaining near-
line electronic databases of paper files on properties , tax records and
dead recording.