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Ask HN: Does RAID 1 of 3 HDD offer any protection against bitflip on 1 of drives

by kokojumbo on 1/25/23, 12:43 AM with 2 comments

Theoretically if 3 HDD are set up in RAID 1 - meaning every disk has same content and bit flip happens to the bit on one of them 2 other disks can be used to "vote" which value of bit being read should be "chosen as correct one by majority of votes". Does RAID 1 of 3 HDD make use of that fact in any way?

Of course bit flips can happen for same bit on 2 HDD at the same time but such cases potentially could be very very rare.

by WantonQuantum on 1/25/23, 12:50 AM
No, in a RAID 1 configuration (of any number of drives) writes are written to all drives and each read comes from only 1 drive.
Depending on the implementation, reads can be spread across drives but no parity is checked.