RAID REDUNDANT ARRAY OF INEXPENSIVE DISKS

Why RAID?

APPLICABILITY Large Data Transfers Numerous Small Transfers

RELIABILITY STORAGE CAPACITY PERFORMANCE - MTTF -Data Transfer Rate -I/O performance

Parity |

RAID levels

RAID 0: NON-REDUNDANT STRIPING Disk 0 Disk 3 Disk 2 Disk 1

RAID 1: MIRRORED DISKS Disk 0 Disk 3Disk 2 Disk 1

RAID 2: HAMMING CODE Disk 0 Disk 3 Disk 2 Disk 1 Disk 4 Disk 6 Disk 5 DATA DISKS PARITY OR CHECK DISKS

Hamming Code (ECC)

RAID 3: SINGLE CHECK DISK Disk 0 Disk 3 Disk 2 Disk 1 Disk 5 DATA DISKS PARITY OR CHECK DISK

RAID 4: INDEPENDENT DISKS Disk 0 Disk 3 Disk 2 Disk 1 Disk 5 DATA DISKS PARITY OR CHECK DISK

Disk 5 RAID 5: NO SINGLE CHECK DISK Disk 0 Disk 3 Disk 2 Disk 1

Summary

Conclusions RAID provides an effective solution for disk drive performance and reliability issues Can be adjusted to meet specific requirements Can be hardware or software based