flash memory VS. spinning disks, is best. Often flash memory is used for data that is accessed more frequently and spinning disks for archived and less frequently requested data. Storage Redundancy-Preventing Data Losses The criticality of data requires that storage systems write data to multiple disks. If one disk fails, the data is not lost because it is stored in a redundant disk. In addition to redundant discs within the same storage system, data center operators and cloud computing providers may duplicate the entire storage system in another location. Connections between the main storage and the duplicate system enable real-time updates in the backup system. In this way, if a natural disaster such as a flood or hurricane destroys an entire data center, all data is up to date and preserved. Frequently, only the changes in files are backed up every night. As LANs and WANs became more powerful, SANs began using disk mirroring to back up files in real time. Disk mirroring is the process of simultaneously writing data to backup and primary servers SO that all www.TechnicalPDF.com recent changes are saved and up-to-date, in the event of a failure during working hours. A town in Massachusetts has a duplicated as well as main storage area network. A hacker attacked their main storage system by encrypting all of its data. (With encryption, mathematical algorithms rearrange data into a different format. A key is required to decrypt the data back to its original format.) The hacker refused to decrypt the data unless the town paid a ransom. However, the town refused to pay the ransom because they were able to replace the encrypted data with data from the backup storage system. Nearby towns without a backup storage network did pay a ransom to have their data decrypted. Storage Area Networks-Centralized File Access Storage area networks (SANs) enable the entire organization to share files SO that people do not need their own, personal database. Having an adequate number of channels into the servers connected to storage sy