RAID systems - a word to the wise

Having just watched engineers try and trouble shoot a RAID 5 set with multiple drive failures, built on Microsoft software RAID, I'd like to chuck my hat in the arena on this subject...

Don't make a software RAID 5 set!

The issue with software RAID 5 sets (especially with Windows OS) is that there is no straight forward way of monitoring the drives within the array, and just as important (as the engineers I was with discovered) no easy way of identifying the drives to establish which are the missing devices!?

Modern hardware RAID controllers are ridiculously cheap and perform a vital role in maintaining the resiliency of your data. These cards also offer a vital source of drive behaviour through active monitoring and at the very least can email you when drives start to misbehave.


  1. Be cognizant of read errors as they are a serious issue with RAID. If the disk fails, the RAID will have to read all the disks that remain in the RAID group to rebuild. A read error during the rebuild will cause data loss since we need to read all other disks during rebuild.

    SATA disks experience read failure once every 12,5 TB of read operations, that means if the data on the surviving disks totals 12.5TB, the rebuild is certain to fail.


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