Disaster Recovery : Types Of Replication
Methods , Retention And Destruction
Media types used for backup of data-transfer
Tape: These include Magnetic tape,
DAT (Digital Audio Tape), DLT (Digital Linear Tape).DAT
(Digital Audio Tape) drives are also called 4 mm DAT.
DAT tape is 4 mm in width. DAT tapes can store data
any where between 2 GB and 24 GB(Gig Bytes). The data
transfer speed is approximately 20MB/min. DLT (Digital
Linear Tape) drives: DLT drives can store much larger
capacity, to the tune of 70GB. Transfer speeds for DLT
drives can be as high as 300MB per minute. Mammoth:
This type of tape drive also have high data transfer
capacity, and medium capacity.
Disks:these include optical disks
and removable hard disks.
Optical: optical drive uses laser
to read and write to compact disks and there is no contact
between drive and the disk .This increase drive wear
and longevity. These include CD-RW and recordable DVD
Grandfather-Father-Son: In GFS, "Son" is the incremental
or differential daily back-up, "Father" is the full
weekly back-up, and "Grandfather" is the monthly full
Tower Of Hanoi: Multiple media sets are rotated through
in incremental and full back-ups. It uses more media
sets than GFS for increased safety.
5.2 Given a scenario, compare and
contrast the different types of replication methods
Types of site
Hot Site: these sites allow continuous access to the
server directly or remotely by backup facility to allow
ongoing mirror operations of primary server. Speed of replication
depends on distance between primary site and hot site.
Cold sites: These site allow periodic connection according
to a specific schedule to copy the backup data.
Warm Site: It is a compromise between hot and cold. These
sites will have hardware and connectivity already established,
though on a smaller scale than the original production site
or even a hot site. Warm sites will have backups on hand,
but they may not be complete and may be between several
days and a week old