Software-Defined Storage

What is software-defined storage?

Software-defined storage is a data storage scheme that all storage-related control functions are implemented in software, removing the software’s dependence on proprietary hardware. It uses standardized hardware (such as x86 architecture) as the carrier to realize enterprise-level storage function and service based on software. Yes, It is not the firmware in a storage device, but a software layer which can ensure that the storage access of the system can be managed more flexibly at a precise level. It is used to control storage request to the physical storage, how and where to store data. Software defined storage is abstracted from hardware storage, which also means that it can become a shared pool that does not care the capacity of the underlying hardware, so as to improve efficiency and reduce costs.  

Compared with the traditional storage hardware box, the storage software has become the core of SDS. The rise of SDS stems from the rapid development of hardware, the maturity, stability, performance of CPU, network, SSD and other hardware continues to improve, at the same time, cloud computing has an urgent demand for the scalability, reliability, high performance and low cost of storage, which makes SDS possible. SDS is usually distributed storage in the form of file storage, object storage and block storage three types. The main open-source SDSs include Lustre、Gluster、Sheepdog、Ceph、BeeGFS、Minio. The main application scenarios includ hybrid cloud, OpenStack private cloud or shared cloud, Kubernetes, etc.

QStora - SDS new entrant

QStora is one of the most innovative new entrant. QStora is a software-defined storage controller, which can convert the commodity servers and their internal Hard Disk Drives (HDDs) and Solid State Drives (SSDs) to a high-performance virtual storage array and provide virtual targets and logical volumes through standard Internet Small Computer System Interface (iSCSI) protocol. QStora is particularly suitable for scenarios such as edge computing, hybrid cloud storage, secondary storage (backup/video surveillance), and hardware utilization enhancement. If deployed in a reliable hardware environment, QStora can even host critical workloads of the enterprises.

The traditional hardware storage array provides low latency and high availability for each logical volume, but has problems of poor horizontal scalability, high cost, and may form many "isolated data islands". That leads to high cost and low utilization of storage resource. Some traditional distributed storage looks quite attracting, but usually has the problems such as complex deployment, bad performance and poor stability.

QStora delivers storage array in a quite different approach.

QStora is a zip package, which can be easily installed on the Linux operating system of any brand and any configuration of physical servers, bare metal servers, virtual machines and even container instances. QStora is completely decoupled with hardware drivers, so users can freely use the latest hardware on the market. Less vendor lock-in!

QStora is green. QStora runs as a group of user-mode processes, does not rely on any specific version of Linux kernel or distribution, does not rely on, or modify the operating system environment, does not monopolize the entire hard drive, and does not interfere with the execution of any other processes. Thus, QStora can run in the same Linux operating system instance concurrently with other applications. We call this feature "green". On the one hand, it can help users improve the utilization of existing hardware resource, on the other hand, it also lowers the barriers for potential users to try QStora - even a virtual machine is not needed!

QStora supports heterogeneous hardware. QStora allows each Linux operating system instance in the cluster to have different hardware configurations, such as different numbers of CPUs, different sizes of memory, different capacities of local hard drives, etc. QStora always does its best to provide the best performance. It can help users further improve the utilization of existing hardware resource.

QStora is high-performance. QStora adopts distributed dual-controller architecture to provide the low latency and high availability just like traditional hardware storage array, as well as high scalability and high throughput just like traditional distributed storage. It can scale from the 3 servers to thousands of servers immediately and shrink from thousands of servers to 3 servers one by one without service unavailability.

QStora is high-quality. QStora is designed to guarantee the data durability of each logical volume as long as the number of simultaneous disk faults in the cluster is not greater than the allowed fault number of logical volume's redundancy mode (for 3-replica mode, the allowed fault number is 2; for Erasure Code N+M mode, the allowed fault number is M). QStora is also designed to guarantee the service availability when any single server, link or disk fault occurs in the cluster. QStora has been sufficiently tested in complex and large-scale environments before release.

In summary, not only can QStora offer low latency and high availability just like traditional hardware storage array, but also high scalability and high throughput just like traditional distributed storage. The feature of green will help users largely reduce the cost of deployment and the feature of heterogeneous hardware support greatly improves the utilization of existing hardware resource.

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