CCIE network engineers must know:Basic concepts of storage virtualization
Basic concepts of storage virtualization
First of all, what is storage virtualization? Storage virtualization means that by adding a logical layer to the storage device, the administrator can access or adjust storage resources through the logical layer to improve storage utilization. This facilitates centralized storage devices and provides better performance and ease of use.
Storage virtualization includes host-based storage virtualization, storage device-based virtualization, and network-based storage virtualization.
Host-based virtual storage relies on agents or management software, which can be installed and deployed on one or more hosts to achieve storage virtualization control and management. The scalability of this method is poor, and the actual performance is not very good. Because this method requires the installation of control software on the host, the failure of one host may affect the integrity of the data in the entire SAN system. Host-based virtualization is easier to implement and has the lowest equipment cost.
Storage virtualization based on storage devices is through third-party virtualization software. Storage-based virtualization usually only provides an incomplete storage virtualization solution. This technology is mainly used inside the same storage device for data protection and data migration. The advantage is that it has nothing to do with the host, does not occupy host resources, and has rich data management functions. It is easy to coordinate with the equipment of a specific storage vendor, so it is easier to manage.
The network-based virtualization method is to implement storage virtualization functions between network devices:
1. Virtualization based on connected devices
Virtualization methods based on connected devices can run on dedicated servers, using standard operating systems, such as Windows, Linux, or operating systems provided by vendors. This method has many advantages of the host-based method—easy to use and cheap equipment. However, the device-based method also has some shortcomings. Machine failure or improper host configuration may lead to access to unprotected data.
2. Router-based virtualization
The router-based approach is to implement storage virtualization on the router firmware. In this method, the router is placed in the data channel from each host to the storage network to intercept any command from the host to the storage system in the network. Since it does not rely on a proxy server running on each host, this method has better security than host-based or device-based methods. When the router connecting the host to the storage network fails, the data on the host may still be inaccessible. However, only hosts connected to the failed router will be affected, and other hosts can still access the storage system through other routers. The redundancy of the router can support dynamic multi-path, which also provides a solution to the above-mentioned failure problem.
Network-based storage virtualization is achieved by adding a virtualization engine to the storage area network (SAN). Mainly used for the integration of heterogeneous storage systems and unified data management. Its advantages are: first, it has nothing to do with the host and does not occupy host resources; second, it can support heterogeneous hosts and storage devices; third, it can unify the data management functions of different storage devices; fourth, it can be built Unified management platform, good scalability. But there are also shortcomings: first, some manufacturers have weak data management functions, and it is difficult to achieve the purpose of virtualized unified data management; second, some manufacturers have low product maturity and still have compatibility problems with different storage and hosts.
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