Читать книгу VMware Software-Defined Storage - Martin Hosken - Страница 4

I had just completed the final chapter of the Virtual SAN book I was working on when Martin reached out and asked if I wanted to write a foreword for his book. You can imagine I was surprised to find out that there was another person writing a book on software-defined storage, and pleasantly surprised to find out that VSAN is one of the major topics in this book. Not just surprised, but also very pleased. The world is changing rapidly, and administrators and architects need guidance along this journey, the journey toward a software-defined data center.

When talking to customers and partners on the subject of the software-defined data center, a couple of concerns typically arise. Two parts of the data center have always been historically challenging and/or problematic – namely, networking and storage. Networking problems and concerns (and those related to security, for that matter) have been largely addressed with VMware NSX, which allows virtualization and networking administrators to work closely together on providing a flexible yet very secure foundation for the workloads they manage. This is done by adding an abstraction layer on top of the physical environment and moving specific services closer to the workloads (for instance, firewalling and routing), where they belong.

Over 30 years ago, RAID was invented, which allowed you to create logical devices formed out of multiple hard disk drives. This allowed for more capacity, higher availability, and of course, depending on the type of RAID used, better performance. It is fair to say, however, that the RAID construct was created as a result of the many constraints at the time. Over time, all of these constraints have been lifted, and the hardware evolution started the (software-defined) storage revolution. SSDs, PCIe-based flash, NVMe, 10GbE, 25GbE (and higher), RDMA, 12 Gbps SAS, and many other technologies allowed storage vendors to innovate again and to make life simpler. No longer do we need to wide-stripe across many disks to meet performance expectations, as that single SSD device can now easily serve 50,000 IOPS. And although some of the abstraction layers, such as traditional RAID or disk groups, may have been removed, most storage systems today are not what I would consider admin/user friendly.

There are different protocols (iSCSI, FCoE, NFS, FC), different storage systems (spindles, hybrid, all flash), and many different data services and capabilities these systems provide. As a result, we cannot simply place an abstraction layer on top as we have done for networking with NSX. We still need to abstract the resources in some shape or form and most definitely present them in a different, simpler manner. Preferably, we leverage a common framework across the different types of solutions, whether that is a hyper-converged software solution like Virtual SAN or a more traditional iSCSI-based storage system with a combination of flash and spindles.

Storage policy–based management is this framework. If there is anything you need to take away from this book, then it is where your journey to software-defined storage should start, and that is the SPBM framework that comes as part of vSphere. SPBM is that abstraction layer that allows you to consume storage resources across many different types of storage (with different protocols) in a simple and uniform way by allowing you to create policies that are passed down to the respective storage system through the VMware APIs for Storage Awareness.

In order to be able to create an infrastructure that caters to the needs of your customers (application owners/users), it is essential that you, the administrator or architect, have a good understanding of all the capabilities of the different storage platforms, the requirements of the application, and how architectural decisions can impact availability, recoverability, and performance of your workloads.

But before you even get there, this book will provide you with a good foundational understanding of storage concepts including thin LUNs, protocols, RAID, and much more. This will be quickly followed by the software-defined storage options available in a VMware-based infrastructure, with a big focus on Virtual Volumes and Virtual SAN.

Many have written on the subject of software-defined storage, but not many are as qualified as Martin. Martin is one of the few folks who have managed to accrue two VCDX certifications, and as a global cloud architect has a wealth of experience in this field. He is going to take you on a journey through the world of software-defined storage in a VMware-based infrastructure and teach you the art of architecture along the way.

I hope you will enjoy reading this book as much as I have.

Duncan Epping

Chief Technologist, Storage and Availability, VMware