RAID-5 vs RAID-4 with SSDs

OWC Thunderbay Mini

Thunderbay Mini configurations start at about $379 without drives. Thunderbay Mini RAID-5 edition also available.

RAID-4 is striping with a dedicated parity drive
RAID-5 is striping with distributed parity

MPG tested the throughput of the OWC Thunderbay 4 Mini using DiskTester run-sequential-suite on a late 2013 MacBook Pro Retina (Thunderbolt 2).

disktester run-sequential-suite --xfer-steps 4 --test-size 2G--starting-xfer 64K --ending-xfer 256MB

With 4 OWC Mercury Extreme Pro 6G SSDs, RAID-4 outperforms RAID-5 by about 10% for reads (compare green and blue lines). Write performance is identical.

Findings might or might apply to hard drives, whose performance characteristics differ from SSDs.

OWC Thunderbay Mini performance: 4 OWC 6G SSDs, RAID-4 vs RAID-5 for varying transfer size

Filling the entire volume with disktester fill-volume, observe that write speed for RAID-4 and RAID-5 is identical on SSDs. But read speed is about 12% higher for RAID-4.

disktester fill-volume --xfer 128M

OWC Thunderbay Mini performance: 4 OWC 6G SSDs, RAID-4 vs RAID-5 sustained transfer speed