Data Backup
A RAID system used as secondary storage is not an alternative to backing up data. In parity configurations, a RAID protects from catastrophic data loss caused by physical damage or errors on a single drive within the array (or two drives in, say, RAID 6). However, a true backup system has other important features such as the ability to restore an earlier version of data, which is needed both to protect against software errors that write unwanted data to secondary storage, and also to recover from user error and malicious data deletion. A RAID can be overwhelmed by catastrophic failure that exceeds its recovery capacity and, of course, the entire array is at risk of physical damage by fire, natural disaster, and human forces, while backups can be stored off-site. A RAID is also vulnerable to controller failure because it is not always possible to migrate a RAID to a new, different controller without data loss.
Read more about this topic: RAID
Famous quotes containing the word data:
“Mental health data from the 1950’s on middle-aged women showed them to be a particularly distressed group, vulnerable to depression and feelings of uselessness. This isn’t surprising. If society tells you that your main role is to be attractive to men and you are getting crow’s feet, and to be a mother to children and yours are leaving home, no wonder you are distressed.”
—Grace Baruch (20th century)