RAID Disk Arrays Redundant Array of Independent Disks (D:) File RAID Storage - Multiple disks working cooperatively - Improve performance and reliability of the storage System Concepts system by storing redundant data Forensics - Physical View of Array - Individual drives that compose array RAID is a set of physical disk drives viewed by - theLogical OS as Viewa single of Arraylogical drive. Data- Appears are distributed as a single across disk the on physicala system drives Digital Forensics Center THINK BIG WE DO - ofThere an array are 7in RAID a scheme Configurations known as striping, Department of Computer Science and Statics described subsequently. - Can arrays can be configured by Redundant disk capacity is used to store U R I parity- Hardware information, Controller which guarantees data recoverability in case of a disk failure. http://www.forensics.cs.uri.edu - Software Drivers and Formatting Utilities RAID Disk Arrays RAID Disk Arrays RAID 0 1 TB Mirrored arrays - Not true RAID + - RAID 1 - No error checking or redundancy 1 TB - Mirroring or shadowing keeps duplicate + of each disk. - Data is placed across all drives for increased 1 TB - Each pair of disks contain the exact speed copy 1 TB + same stores of data - Each drive receives an + Data 1 TB - Provides Data entire byte or block 1 TB + copy - Byte striping gives high transfer rate - Faster access to data X + 1 TB - Block striping gives higher performance in - Redundancy of data 1 TB + copy transactional environment when disk operate - When there is a read failure 3 TB independently 1 TB - bad block is marked and then read from the and 3 TB 6 TB mirrored drive duplicate copy RAID Disk Arrays RAID Parity Levels RAID 453 - Use parity bits for correction and RAID 6 detection of errors 1 TB RAID Storage + - Parity records number of 1's 1 TB - Parity bit of 0 - even number of 1's + Concepts Parity Bytes 1 TB - Parity bit of 1 - odd number of 1's + DataData andBlocksBits or Bytes 1 TB - RAID 2, RAID 3 + Parity Bits - Bit/Byte-level striping 1 TB Data 5 TB Digital Forensics Center - Byte level parity Department of Computer Science and Statics THINK BIG WE DO - RAID 4, RAID 5, RAID 6 Parity - Block-level striping Drive U R I - Block level parity http://www.forensics.cs.uri.edu.