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Old 20th September 2021
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jggimi jggimi is offline
More noise than signal
Join Date: May 2008
Location: USA
Posts: 7,782

RAID (other than RAID 0) provides some redundancy for select types of drive failures. It isn't a backup solution.

What RAID will do:
  • RAID will keep your system running without data loss only when there is a hardware failure of a disk drive, as long as the type of drive failure is one where the OS can survive and continue operation, such as permanent read failures.
What RAID won't do:
  • RAID will not prevent data loss when either programmatic or operator errors cause overwritten or erased data. Errors are written to the array, redundantly. In fact, RAID will not protect the system from any software errors or operator errors of any kind.
  • RAID will only protect a system from certain types of disk drive hardware failures. All other single points of failure remain. High-Availability ("HA") computing and HA network infrastructures are options to consider either with or without RAID solutions.
Proprietary "Hardware RAID" offerings have one additional consideration that generic software RAID solutions do not. During a failure you will not be able to move drives from the vendor's array to some other storage platform in order to use or recover data. Therefore, you will need to ensure access to spares and ensure you can obtain vendor support over the planned operating lifespan of the array. Consider an extended service contract post-warranty, consider purchasing spare parts in advance, and consider a retainer for consulting services with the vendor's sustaining engineering services. Really.

Last edited by jggimi; 20th September 2021 at 03:25 AM. Reason: clarity
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