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
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