1. Abstract This documentwill represent hard disk mirroring method and characteristics , advantages anddisadvantages , Points of failure . 2.Introduction The term RAID was coined in1987 by David Patterson, Randy Katz and Garth A. Gibson. In their 1988 technicalreport.Disk mirroring or it’s called “redundant array of independent disks” (RAID) is a technique used to protect computer systems fromlosing data or any potential losses due to disk failures.
In this technique, Datawill duplicated by saving data in two or more identical hard drives, All harddrives are connected on one disk controller card. If one hard drive fails, thedata can be taken from other mirrored hard drives.The figurebelow illustrates RAID meaning: 3. Problemdefinition Disk mirroring(RAID) is technique found to protect data because any system can be break .After this calamity data will be available whenever you reach this point .Also, It increases the data acceleration access. 4.
RelatedworkAs written inthe problem definition section there are many solutions to solve this problem suchas “Placing Related Blocks on Cylinders ” to increase access speedthis technique read on the same cylinder in the same time . And there is manyother related techniques … 5.
Comparisim 5.1 Evaluation At the hard disk drive data retrievalevaluation process, all media obtained goes through an analysis to recognizethe real shape of the drive. Few steps to follow through the hard disk drivedata retrieval, and these comprise the following: 1. The hard disk drive data recovery experts will determine whether the issues are physical,logical, or both. Issues refer to those that happen in the hardware, whileplausible problems occur on the applications structures. 5.2 CriticismFirst ,Needing too much of memory capacity ; Becauseall data written twice or more.
It havea complex technology . Furthermore, Replacing and restoring the data from alarge file to smaller one may take long time (one or more day) depending on thespeed of controller . 5.3 Gaps Frequently RAID server has singlecontroller. If the server failure will result in all single point of failure.Also , Lossof RAID configuration settings or system registry can make a failure .
6. DiscussionIn the 1988 authors determines sixlevels of RAID, 0 through 5. This numbering system content uses of redundant dataacross the array. This number classified intothree categories: standard, nested and nonstandard RAID levels. Incase a drive fails, Data just have to be copied to the replacement drive.
Accessdata transactions are very fast while write data transactions are somewhatslower . 7.Conclusion Hoping that my report is beneficial and you well understood RAID characteristics.