Backups, Snapshots and Arrays, oh my!
There seems to be some confusion about what qualifies as backups and what doesn't. I'd like to take a minute to clear this up. Backup : According the Merriam-Webster.com, a backup would be defined as "a copy of computer data"... emphasis on the word " copy " First, let me cover what snapshots are in almost every system that uses them. A snapshot goes through certain steps: 1 ) Snapshot is requested 2 ) System (be it virtualization system, OS or array henceforth referred to collectively as "system") quiesces the data to commit any buffered data 3 ) Data is locked by the system (now referred to as source) 4 ) Change log is created (referred to a "new data") 5 ) As data changes are requested, pointers are created that reference the source with the new data updated. As more data is updated, the change log can grow up to the size of the original source data 6a ) New snapshot (multiple snapshot config): change log is frozen like the o