Virtual Infrastructure Security

Transcription

1 Virtual Infrastructure Security

2 2 The virtual server is a perfect alternative to using multiple physical servers: several virtual servers are hosted on one physical server and each of them functions both completely and independently. There is no change in functionality and services offered by websites that are hosted on virtual servers; they achieve the same effect as if they were hosted on dedicated servers, can be easily reduplicated and allow for fast deployment within a server environment. Virtual infrastructure is the next generation server environment and is designed to address the inefficiencies of the in-house server model and the limitations of dedicated servers. Backing up is the procedure of copying and archiving digital files for two purposes: 1. To recover data after system failure or corruption and to achieve proper system functioning. 2. To recover and manage data from an earlier time (according to data retention options). The following schemes are actual examples of physical and virtual server functioning: 1. The first and cheapest way to avoid data corruption on a server is periodic backing up, which is performed to backup storage or cloud storage. There are two ways of backing up: periodic and incremental. With periodic backup, all files are sent to a backup storage location and with an incremental backup, only files which have been changed are stored for backup. The main advantages of this method are its ability to recover the system from any restore point and to protect it from viruses. The disadvantage is that restore points are created at quite long intervals, so data loss is inevitable. This method is usually used for low-end businesses.

3 3 The cluster scheme is more complicated but provides fail-safe server functioning and helps protect hardware. There are two or more hosts with many virtual VMs installed on them that are related by network link. One of the servers duplicates all of the processes and transactions of the other this method is called mirroring. All the backup information from servers is directed to a backup server and then filed to backup storage. If any host fails, its VMs immediately migrate to other servers within the cluster and continue working, so data loss and downtime are minimal. Creating server mirrors is quite an expensive method since each server needs another server whose only purpose is to be a copy. The alternative method is clustering connecting two or more computers together in such a way that they behave as a single computer. It is a less expensive technique that is becoming more and more popular. But the disadvantage of this method is software vulnerability if a system fails because of a virus, both hosts will become corrupted with it. The replication method allows for locating hosts remotely, not only in the next room but even in different cities or countries, and it is used mainly in small and medium businesses. Replication not only copies a database but also synchronizes a set of replicas so that changes made to one replica are reflected in all the others. Snapshots of VMs at the main host are periodically copied to another host along with the usual backup procedure. In case of system failure on the main host, the VMs start up from the snapshots on the remote host. After the system restore the replication procedure is started conversely according to the disaster recovery scenario.

4 4 The main aim of using replication other than for usual backup purposes is to test the system. A feature or system update that is needed is launched on a remote host and tested there. Then, if it proceeds as expected, it is granted permission to start on the main host. This method enables many users to work with their own local copy of a database but have the database updated as if they were working on a single, centralized database. In addition, and very importantly, this method protects hardware from viruses and accidental system failures since its main advantage is the remote location of its hosts which make it especially efficient for distributed users globally. 2. The method of full data protection includes mirror, replication and backing up processes at the same time. This provides the advantage of recovering system functioning in minimal time with no data loss.

5 5 3. The perfect (and most expensive) data protection method used in large corporations includes not only physical storage, but also cloud servers and storage. This method provides the benefits of greater accessibility and reliability, rapid deployment, solid protection for data backup, archival and disaster recovery purposes and lower overall storage costs as a result of not having to purchase, manage and maintain expensive hardware. In this scheme there can be many backup servers that are periodically synchronized, so backing up here isn t only for servers but for datacenters and servers together, as well. Mutual replication and synchronization of backup storage are periodically performed for system security.