Alibaba’s dual-mode SSD platform raises bar for storage performance

The growing use of artificial intelligence and big data has put a strain on hyperscale datacentres, particularly traditional, standardised storage infrastructure that has been unable to adapt to different I/O requirements.

Standardised storage, while offering backward compatibility and portability, use a generic block I/O interface that host software such as an operating system has no control over. That means the host would not be able to manage the physical storage according to varying performance needs.

To solve this problem, open-channel SSDs (solid-state drives) were developed to expose the internal parallelism of SSDs to a host, enabling these devices to support I/O isolation and more predictable latencies.

Chinese cloud service provider Alibaba Cloud has taken things further when it announced that it has developed AliFlash V3, a dual-mode SSD that supports both open-channel mode and native NVMe mode (mainly for compatibility purposes), as part of an new storage platform that closely integrates hardware, firmware, drivers, operating system and applications.

The integration is done via the platform’s user-space open channel I/O stack called Fusion Engine that was released in January 2018.

The platform, which Alibaba claims will reduce read latency by 75%, and improve overall storage performance by as much as five times, also supports all levels of customisation – from generic block devices that require no modification to applications, to highly customised software/hardware integrated systems.

The impetus to develop the new storage platform stemmed from Alibaba’s own experience with running applications on standardised hardware like NVMe SSDs. It found that its e-commerce, financial and logistics applications, for example, required features that were not available in standard SSDs.

Moreover, because the company’s application requirements change frequently, its storage infrastructure must be agile and adapt quickly to changing demands. However, due to long production cycles of standard SSDs, it could take quarters to obtain new product releases from SSD suppliers.

Alibaba has written a specification for its dual-mode SSD platform, and is working with different SSD and firmware suppliers in an effort to build an ecosystem around its platform.

Shu Li, senior staff engineer at Alibaba’s infrastructure services team, says the platform is expected to be widely deployed in Alibaba’s datacentres, serving both internal and external customers in future.

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