Their rate will probably be higher since they are utilizing used drives. From the spec:
2,400 drives. Mostly 12TB used enterprise drives (3/4 SATA, 1/4 SAS). The JBOD DS4246s work for either.
2,400 drives. Mostly 12TB used enterprise drives (3/4 SATA, 1/4 SAS). The JBOD DS4246s work for either.
Buying used drives eliminates the high rate of early failure (but does get you a bit closer to the 2nd part of the U-curve).
Typically most drives would become more obsolete before hitting the high failure rate of the right side of the U-curve from longevity (7+ years)