Kioxia Shatters Storage Density with 245TB SSD: A Deep Dive
Kioxia, a leading name in flash memory solutions, has dramatically increased storage capacity with its new 245.76TB Enterprise & Data Center SSD.This leap forward doubles teh previous generation’s 122.88TB limit, marking a critically important milestone in high-density storage.But how did they achieve this, and what does it mean for your data center? Let’s break it down.
The Drive for Density: More Chips, New Format
Kioxia didn’t just tweak existing technology; they fundamentally altered the approach. The new drive utilizes 32 quad-level cell (QLC) NAND chips – a significant jump from the 16 found in previous models. This increase in chip count, coupled with a physically wider and thicker drive design, is the core of the capacity boost.
They’ve also introduced a novel “2T” format for their E3.L drives.Essentially, this combines two 122.88TB cards into a single, higher-capacity unit. This format is key to understanding the trade-offs and benefits of Kioxia’s approach.
How Does Kioxia stack Up Against the Competition?
Kioxia isn’t alone in the high-capacity SSD space. Phison and Solidigm also offer 122.88TB drives, but performance varies due to different architectural choices. Here’s a fast comparison:
Solidigm D5-P5336: Max write throughput of 7.4GBps, max write speed of 3.2GBps.
Phison Pascari D205V: Max write speed of 3.2GBps, read speeds up to 14.7GBps with PCIe 5.0.
Kioxia LC9: Around 3GBps for writes and 12GBps for reads.
Interestingly,Kioxia’s LC9 uses the same controller as Phison’s,yet delivers slightly slower write speeds. The reason? Kioxia suggests potential optimizations in areas like onboard RAM to achieve the higher capacity.
Performance nuances: IOPS and Caching
While kioxia’s write speeds are a bit lower, it excels in random writes. The LC9 boasts 50,000 input/output operations per second (IOPS), surpassing the 35,000 IOPS of the Phison drive and the 25,000 IOPS of Solidigm.
However, random read performance tells a different story:
- Phison: 3 million IOPS
- Kioxia: 1.3 million IOPS
- Solidigm: 930,000 IOPS
These results are complex. Firmware intelligence, which predicts frequently accessed “hot” data and caches it, plays a significant role.The Phison drive benefits from dedicated RAM for caching,a feature absent in the Kioxia model. Solidigm’s drive, already limited by PCIe 4.0, also has less cache than Phison.
The QLC Factor: Why Writes are Slower
It’s crucial to understand why writes are generally slower on QLC SSDs. QLC technology stores four bits of data in each cell. This requires the firmware to:
copy existing data to RAM. Erase the cell electrically.
write the updated data,either to the original cell or a new one with the same logical address.
This process is inherently more complex than with technologies storing fewer bits per cell.
form Factor and Scalability: The 2U Array Impact
The 245.76TB capacity comes with a physical footprint consideration. Kioxia’s E3.L format is 14.22cm deep, compared to the 11.28cm of the E3.S format. This impacts density within a 2U storage array:
2U array with 122.88TB SSDs: Approximately 2.9PB of raw capacity (24 drives).
