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NVMe®2简介.0、未来的flash

美光科技| 2021年7月

NVM Express® 标准，或NVMe®, ssd的领先接口技术是什么, used by the vast majority of computing systems from data centers to laptops to cell phones. 6月2日, 2021, NVM Express publicly released a suite of specifications for nonvolatile 内存 across a broad range of applications. 除了完全重组现有的规范，NVMe 2.0增加了许多重要的新特性. NVMe committee members and users are excited by this next step forward. 让我们来看看为什么.

传统硬盘驱动器的一个限制是, if the next block of data you need is on the other side of the actual physical disk, you have to wait for the disc to spin around until it reaches the read head. 基于闪存的固态硬盘就没有这个问题, 当然:每个街区都是相同的“距离”. But the old interface standards were written with that limitation in mind. 第一个NVMe规范, 发布于2011年, was written to set 固态硬盘s free and allow applications to make the most of the extra performance.

有什么新鲜事?

该规范的最后一个公开版本是NVMe 1.4(2019年6月10日)，其中包括三个规格:

  • NVMe基础规范
  • NVMe Management Interface (MI)规范, 哪些涵盖了与监视相关的操作, 通过“带外”机制配置和管理NVMe设备, meaning that these operations are kept separate from read/write operations
  • NVMe over Fabrics (NVMe- of)规范, 增加了对网络协议的支持, 使构建高性能存储网络成为可能, 或“面料”

对于NVME 2.0, the specification has been refactored to enable “faster and simpler development.” Rather than one very large document, specific areas have been separated from the base document. These should give users a 清晰的 idea of where to go for information on a specific topic, 尽管可能需要使用多个文档. 因此，现在有八种规格:

  • NVMe基本规格.0
  • NVM命令集规格.0
  • 分区命名空间命令集规格.0
  • PCIe传输规范1.0
  • 管理接口1.2
  • RDMA传输规范.0
  • TCP传输规范1.0
  • 键值命令集规格.0

下面的图表显示了它们是如何组合在一起的.

NVM Express公司. 图 图:NVM Express公司.

In addition to the refactoring, a variety of new and important features have been introduced:

分区命名空间(ZNS)

This is an important development that helps applications achieve higher performance while improving the longevity of NAND-based storage. Instead of many drives arbitrarily organized into one or more logical drives, ZNS allows one drive to appear as multiple drives assigned to different threads. The specification defines zoned namespaces and the associated Zoned Namespace Command Set. A zoned namespace divides the logical address space of a namespace into zones. Each zone is a logical block range that is written sequentially, but if rewritten, it is reset. The interface allows zoned namespaces to expose natural boundaries for internal device structures and to offload management of internal mapping tables to the host.

NVM集和耐力组管理

微米 was active in the development of this feature since it allows various types of 内存 (e.g.、SLC、TLC等.)用于特定的应用. It defines an interface for interoperable management of endurance groups and NVM sets. 这允许对域进行配置和管理. Endurance groups are analogous to auto-tiering of hot and cold storage but geared toward data that needs to be accessed often, 但不一定很快.

简单复制命令

This feature defines a simple copy command used by the host to copy data from one or more source logical block ranges to a single consecutive destination logical block range. Data can be copied within the device without having to transfer data across the PCI Express (PCIe) interface, 这样可以减少接口流量，从而提高性能.

域和分区

This feature expands NVMe architecture by defining capabilities to enable large scale environments with different domains and the possibility of partitioning of domains. It will be useful when multiple flash types are available on a single device (e.g.、SLC、TLC、QLC等.) and allows parts of the system to be offline for maintenance while the rest keeps going.

命令和功能锁定

This is a significant security enhancement that allows hosts and management entities to prohibit the execution of some commands and Set Feature command features. 例如, 可能允许对特定驱动器执行普通的读/写命令, 但是所有的管理命令都可能被锁定.

名称空间类型

This feature extends the NVMe architecture to support different types of namespaces. 例如, namespaces may contain logical blocks that have special access rules or namespaces that contain things other than logical blocks, 就像键值对的情况一样.

旋转的媒体

此功能为传统硬盘驱动器增加了NVMe支持. It is a good example of how NVMe is trying to broaden its scope and simplify the ecosystem by allowing a variety of persistent media to be connected using a single storage connection.

前进

It’s important to follow these specifications since there are already multiple changes being requested to the 2.0规范. 还有一些事情要做:每个I/O键, 分区随机写区(ZRWA), 计算存储. These are all important and complex features that are in active development, 我将在以后的文章中对此进行探讨.

One of the big questions for driver and 固态硬盘 vendors is: What is the minimum set of changes necessary to move from 1.4 to 2.0? This is an important discussion but one that gets really technical really fast. We have a perspective on this that we’d be happy to share, so please reach out to me (whubis@micron.Com)，如果你想进一步探索.

美光一直是NVMe 2的重要支持者.0规范 and a contributor to the development of many of these new features that open up a lot of really interesting possibilities for system architects and application developers. 继续前进, we’ll continue to take an active role in introducing new and valuable features to this specification to benefit users of our persistent storage.

有关美光NVMe固态硬盘的更多信息，请 访问microron的数据中心固态硬盘页面.com