zfs scrub enable by default

[John Long]

On 05/08/2020 13:15, Bob Friesenhahn wrote:
> On Tue, 4 Aug 2020, Karl Denninger wrote:
> 
>> Let me give you two allegedly "degenerate" cases that are actually not 
>> degenerate at all.
>>
>> 1. A laptop or workstation.  It is backed up.  It uses ZFS because 
>> it's faster, and I can establish a filesystem for some project very 
>> easily and quickly, it's segregated, I can work on it and destroy it 
>> trivially when done.  I can set quotas on that, etc.  If I want to 
>> move its mountpoint, I can trivially do so. And so on.  Note that here 
>> there is no redundancy at all; no raidZx, no mirroring, etc.  I'm 
>> merely using it for convenience.
> 
> Did you remember to set copies=2 or copies=3 for zfs filesystems where 
> you hope not to experience data loss?  It needs to be set as soon as 
> possible since it only applies to new files.  This is a way to get more 
> media redundancy, although the whole drive may fail.

Does copies=n actually create n-1 additional physical copies or is it 
copy-on-write, or something else yet?

/jl