Towards Exascale Racks

Following the recent announcement with the Open Flash Platform initiative, a few weeks ago, we wish to insist on one of the objective of the initiative with the exascale rack.

So we tried to assess what we can do today on the market in terms of rack capacity with SSDs and HDDs. So today, is it possible to deploy 1EB in one single rack? And we invite you to send us remarks as this article could be a start of an interaction. Obviously all numbers are raw or native without any data reduction. We also don’t consider here SSDs without NVMe support like Nimbus Data ExaDrive which uses SAS. Also we don’t pay attention on the energy, processing or connectivity dimensions but just the storage capacity.

The first configuration could group 32 61.44TB E1.L SSD in 1U server that gives almost 80PB in a full rack. This is the case if we pick Solidigm D5-P5336 61.44TB in E1.L format and Supermicro 1U server illustrated below. And we can imagine when 122-128TB SSD are considered, it gives 160PB. And we let you judge when 250 or 512TB will be available.

For the second model we take the Huawei Pacific 9928 with 36 SSDs of 61.44TB and soon 122TB in 2U so it provides today 44PB and soon 88PB in a full rack. With 256TB, it will grow to 160PB in a rack and 320PB with 512TB SSD in the future if the SSD density is maintained.

The third approach is the one we introduced recently when we unveiled to the world Novodisq discovered at FMS. One blade offers 576TB in 2U so a full 2U can be populated with 20 blades for 11.75PB and it gives 235PB in a full 40U rack. With 256TB SSD, 1 blade would deliver 1024TB for 409PB in a full rack and more than 800PB with 512TB.

Clearly the 245-256TB SSDs announced recently by several vendors – Sandisk, Kioxia, SK hynix, Samsung or Micron – will definitely be the central part of this dense rack.

But it also means that some new designs are probably needed, both for rack, chassis and SSD form factors.

Based on numbers we show above, exabyte scale rack is a direction probably around a 3-5 years horizon if trends are maintained. Again today the market can deliver 1/4 of it.

And what can we do with HDD? Several vendors promote such approach as a capacity tier but it offers less capacity than SSDs. If you consider 5U chassis with 120 drives or 4U with 102 drives, it finally gives around 30PB in a 40U rack.

Click to enlarge