What percentage of disk volume is made redundant in RAID1 to RAID5 arrays?
By submitting your personal information, you agree that TechTarget and its partners may contact you regarding relevant content, products and special offers.
RAID1 or RAID0+1 have 50% redundancy. In other words, all data is written onto two disks. RAID5 and RAID4 depend on the number of disks in the array.
The percentage of redundancy is trivial to calculate - it is 1/#_of_disks_in_array.
3 disks is the minimum in RAID4 or RAID5
3 disks in array = 33% redundancy
4 disks in array = 25% redundancy
5 disks in array = 20% redundancy
There can be many disks in an array if you desire however, the reliability decreases as the number of disks increases and the time to loss of data also increases as the number of disks increases. (Second disk failure prior to a parity rebuild being done on the array.)
Editor's note: Do you agree with this expert's response? If you have more to share, post it in one of our .bphAaR2qhqA^0@/searchstorage>discussion forums.
Dig Deeper on SAN technology and arrays
Related Q&A from Marc Farley
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.