----- Original Message ----- From: "kishor bhagwat" aaaaarrrgghhh@yahoo.com To: linuxers@mm.ilug-bom.org.in Sent: Friday, February 21, 2003 8:46 PM Subject: Re: [ILUG-BOM] Re: About RAID
RAID was designed to be a Redundant Array of INEXPENSIVE Disks - but the originators realised that the goals they were trying to achieve - of data protection and performance, werent acheivable with inexpensive disks.Hence the 'I' in the acronym now stands for Independent!!
When they talk of Inexpensive Disks, they are not taking of a comparison between ide drives and scsi drives. They are talking about the cost differential between small capacity scsi drives against using a large capacity scsi drive. For example, a 100GB scsi drive may cost (hypothical cost --- I have no idea how much they actually cost) Rs. 50000, but using 5 scsi drives of 20GB each would cost (again hypothical) Rs. 20,000, giving the same result and better safety. That is why it was called Redundant Array of Inexpensive Disks.
Please remember that at the time when this term came into being, the smaller capacity hdds were much cheaper than the proportionate cost of a larger hdd. There was a premium on higher capacity drives because, first few companies could make it and because the tools available were not good enough to work with multiple drives (you didnt have vertual server and consolidation / transparent clustering accross the network or concepts like Network Area Storage). Since this pricing does not hold true today, the description of raid has changed to Redundent Arrey of Independent Disks
Regards Saswata