The application of virtualization storage technology can save us a lot of money investment

In the storage domain, the application of virtualization storage technology can save us a lot of capital investment, reduce the pressure of enterprises. Through virtualization, users will get rid of the complexity of the underlying physical environment, make full use of storage space based on heterogeneous platform, and realize the effective planning of resources on the basis of openness.

Virtualization automates the configuration of storage devices and their space, enabling users to use all of the physically dispersed storage resources within a domain to manage unpredictable events across regions, such as business discontinuities, adjustments to capacity requirements, and employee changes. Regardless of the location, size, type, and manufacturer of the storage domain where these storage resources are located, they are managed from a single logical view.

The distinction of virtualization storage technology

(1) host-based Virtualization Storage Technology

host-based Virtual storage relies on agents or management software that is installed on one or more hosts to achieve control and management of storage virtualization. Because the control software is running on the host, this will occupy the processing time of the host. Therefore, the extensibility of this method is poor, and the performance of the actual operation is not very good. Host-based methods can also affect system stability and security, because it can lead to inadvertent access to protected data. This approach requires that the appropriate control software be installed on the host, so a failure of one host can affect the integrity of the data throughout the San system. The storage virtualization of software control may also cause unnecessary interoperability overhead due to differences in hardware and software of different storage vendors, so the flexibility of this approach is also poor.

However, because no additional hardware is required, host-based virtualization methods are easiest to implement and have the lowest cost of equipment. Vendors using this approach tend to be software vendors in storage management, and there are already mature software products. These software provide a user-friendly graphical interface for easy management and virtualization of Sans, with good load-balancing mechanisms in both host and small San architectures. In this sense, host-based storage virtualization is a good cost-effective approach.

(2) storage device based virtualization storage technology

Storage-device-based storage virtualization methods rely on enclosures that provide related functionality. Without third-party virtual software, storage based virtualization often provides an incomplete storage virtualization solution. This approach does not work well for SAN storage systems that contain multiple vendor storage devices. Functional modules that depend on the storage vendor will exclude the use of jbods (ethically a Bunch of workloads, simple hard disk groups) and simple storage devices in the system because they do not provide storage virtualization functionality. Of course, using this approach means that a single storage vendor will eventually be locked out.

The storage-based virtualization approach also has some advantages: This approach is easier to implement in a storage system and easier to manage with the device of a particular storage vendor, so it is more manageable and transparent to users or managers. However, we must note that because of the lack of sufficient software to support it, this makes the solution more difficult to be customized and monitored.

(3) web-based Virtualization storage Technology

The network-based virtualization approach is to implement storage virtualization between network devices in the following ways:

① Virtualization storage technology based on interconnected devices

If the method is symmetrical, the control information and the data are on the same channel, if it is asymmetric, the control information and the data are on the different channel. In a symmetrical way, interconnection devices may become bottlenecks, but multiple device management and load balancing mechanisms can mitigate bottlenecks. At the same time, in a multiple device management environment, when a device fails, it is also easier to support the server to achieve fault replacement. However, this will result in multiple islands of the San because one device controls only the storage systems it is connected to. Asymmetric virtual storage is more scalable than symmetry because the path of data and control information is separate.

The virtualization approach based on interconnected devices can be run on dedicated servers using standard operating systems such as Windows, Sunsolaris, Linux, or vendor-supplied operating systems. This method runs in the standard operating system, has many advantages based on the host method ——— easy to use, the equipment is cheap. Many device-based virtualization providers also provide additional functional modules to improve the overall performance of the system, achieve better performance and improved functionality than standard operating systems, but require higher hardware costs.

However, the device-based approach also inherits some of the drawbacks of host-based virtualization because it still requires a proxy software or host-based adapter running on the host, and any host failure or improper host configuration can result in access to unprotected data. At the same time, interoperability among heterogeneous operating systems remains a problem.

② Virtualization storage technology based on switch

In a switch-based approach, the functional module for storing virtualization is embedded in the firmware of the switch or on a separate server attached to the switch. Because the storage virtualization feature software is not required to run on each host, a switch based storage virtualization system provides a software-style management module that does not have security issues that may be encountered in a device-or host-based environment. At the same time, more interoperability can be provided in heterogeneous environments. However, the switch is still a bottleneck and can be a sensitive point of failure. Of course, if you do not want a higher surcharge, you can introduce a standby switch for failure replacement on the data channel.

③ Virtual storage technology based on routers

The router based approach is to implement storage virtualization on the router firmware. Vendors often provide additional software running on the host to further enhance storage management capabilities. In this method, the router is placed in a data channel on each host to the storage network to intercept any command from the host to the storage system in the network. Because routers potentially serve each host, most control modules exist in the firmware of the router, which is better and more effective than the host-based and most interconnected devices based methods. This method has better security than host-based or device based methods because it is not dependent on a proxy server running on each host. When a router connecting a host to a storage network fails, it can still cause data on the host to be inaccessible. However, only hosts that are connected to the failed router are affected, and other hosts can still access the storage system through other routers. The redundancy of routers can support dynamic multipath, which provides a solution to the above fault problem. Because routers are often used as a bridge for protocol conversion, a router based approach can also provide interoperability between heterogeneous operating systems and multi-vendor storage environments.

(Responsible editor: The good of the Legacy)