Kioxia releases faster SAS SDD – the 24gig PM6

Update; June 17 – SAS roadmap and performance data added.

Although the NVMe interface is set to rule the fast SSD interface roost, Kioxia has released a PM6 gen 4 SAS interface drive running at 24Gbit/s.

This is double the bandwidth of current 12Gbit/s SAS links, which is good news for system builders wedded to SAS.

SAS technology roadmap to 48Gbit/s.

Otherwise the PM6 looks pretty much like its PM5 predecessor. That 12Gbit/s SAS drive was launched in August 2017 and used Kioxia’s (then Toshiba’s) 64-layer BiCS 3D NAND technology in TLC format. The PM6 gets the benefit of newer 96-layer BiCS tech in the same TLC format, meaning KIoxia can produce drives with the same capacity as before but using fewer dies, so lowering its costs.

Like the PM5, the PM6 comes in write-intensive, mixed-use, and read-intensive versions, with different endurance levels; 10, 3 and 1 drive writes per day respectively. Capacities vary in each case;

  • PM6 WI – 400GB, 800GB, 1.6TB, 3.2TB,
  • PM6 MU – 800GB, 1.6TB, 3.2TB, 6.4TB, 12.8TB,
  • PM6 RI – 960GB, 1.92TB, 3.84TB, 7.68TB, 15.36TB, 30.72TB.

Update: The initial performance data supplied by Kioxia is sequential read bandwidth of up to 4.3GB/second. The PM5 in read-intensive form delivered up to 2.1GB/sec so that improvement is welcome.

Other PM5 performance numbers are; up to 340,000 random read IOPS, 120,00 random write IOPS, and 2.72GB/sec sequential write throughput. Kioxia subsequently said the PM6 has, compared to the PM5 read-intensive model;

  • Up to 54 per cent improved sequential write bandwidth – calculated to be 3.2GB/sec
  • Up to 144 per cent better random read performance – calculated to be 489,600 IOPS
  • Up to 185 per cent greater random write performance – calculated to be 222,00 IOPS

KIoxia tells us the PM6 is a dual-port enterprise drive and is capable of recovering from the failure of two of its dies. The security features include sanitise instant erase (SIE), TCG Enterprise self-encrypting drive (SED) and FIPS 140-2 certification.

PM6 drives are now available for evaluation and qualification. Samples of 30.72TB products are scheduled to be available after August. SSDs based on 24G SAS will soon be available in servers from market leading OEMs. Market availability for the PM6 24G SAS SSD Series is expected in Q4 2020.

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