I'm no math expert but RAIDz1(or RAID5) is dead on larger drives, maybe RAIDz2(or RAID6) is now close to being dead? At what point does this happen to RAIDz3, RAIDz4?(or whatever they call it)
Sounds true, but isn't true, for ZFS.
RAIDz1 is not dead.
1. Many FreeNAS systems run scrubs regularly.(And everyone should!)
2. To each individual drive, a ZFS scrub is functionally identical to a rebuild.
3. Nobody is reporting their drives having even a single error on every scrub.
4. Nobody reports their drives regularly dying during scrubs.
5. Therefore, we can conclude the odds of any drive dying or having an error during a resilver approach zero, not 100%!
6. Even IF you got a single block read error during a resilver, you would lose one block of data and would know where, and you can lose no metadata, because ZFS stores that twice.
RAIDz1 is not dead. If this statement alarms you, you probably Don't Have A Backup. If you feel safer because you have RAIDz2, you probably Don't Have A Backup.