[kevinkeller]

> I don't want to lose data just because a cosmic ray flipped a bit somewhere.

If you have disks set up in RAID 1 or RAID 6, would you still lose data though?

[extesy]

Absolutely. Imagine you are saving a text file to NAS with a super-secret password to your Bitcoin wallet, for example "password". While it was in memory before it reached disk, one bit was flipped and the file contents became "pastword" which OS happily saved on your RAID. And now you've lost your Bitcoins forever.

[benlivengood]

In raid1 all you need is a bit flip in RAM between writing to disks to cause a permanent error (one disk gets the flipped bit, the other does not).

Raid6 will repair single bit errors, assuming a bit wasn't flipped before/during the erasure code calculation when writing the data.

[ttyprintk]

Consider all the RAM along a network transmission. Maybe you’re using authenticated encryption, maybe your transfer has an internal or out of band checksum. Maybe not.