Asdo wrote:

....
Without knowing this I will probably opt for your way: rsync data out, 
starting from the smallest and most important stuff...
...

I had another thought:

If I take the computer offline, boot with a livecd (one of the worst 
messes here is that the root filesystem is also in that array), run the 
raid6 array in READONLY MODE and maybe without spares, then I start a 
check (scrub) ...

If drives are kicked I can probably reasseble --force the array and it's 
like nothing happened, right?
Since it was mounted readonly I think it would be clean...

Only problem would be if 1 or more drives definitively die during the 
procedure, but I hope this is unlikely...
If less than 3 drives die I can still reassemble --force, and take the 
data out (at least SOME data, then if it degrades, reassemble again and 
try to get out data from another location...)

Do you agree?

I am starting to think that during the procedure for taking the data out 
and/or attempt first scrubbing the main problem are write accesses to 
the array, because if rebuild starts on a spare and then fails again and 
then there were writes in the middle... I think I end up doomed. 
Probably even reassemble --force would refuse to work on me. What do you 
think?

Thank you