Dynamic parity logging disk arrays for engineering database systems

RAID (redundant arrays of inexpensive disks) has gained much attention in the recent development of fast I/O systems. Of the five levels, the traditional mirrored disk array still provides the highest I/O rate for small `write' transfers. This is because the mirrored disk array does not have the `small write problem' which is found in other levels of RAID. The authors propose a novel RAID architecture for fast engineering database systems, called a dynamic parity logging (DPL) disk array. A DPL disk array does not have the `small write problem' and can provide much higher throughput than other RAID architectures. The DPL disk array also has a journalling capability, which means that some older design versions are kept for future reference. A queueing model for the DPL disk array is built. Analytical results, supported by simulation, show that the DPL disk array can provide higher `write' throughput when compared to RAID levels 1, 4, and 5