Re: Basic RAID5/6 reshape question

Brad Campbell wrote:

G'day all,

I'm just doing some system upgrades and shuffling some arrays around as 
part of the process.
All my other current questions have been answered by experimentation, 
but one.

I'm going to start with a RAID 6 comprised of 7 x 1TB drives, and 
reshaping to 10 x 1TB.
I'm doing an experiment right now with re-shaping a RAID-5 of 2 drives 
into 3 drives which is taking about 20 hours, from that I'm assuming 
that a nice big re-shape will take a considerable amount of time. I have 
a reliable UPS, I'm more concerned about a drive or cable flaking out.

What happens if I'm in the middle of a reshape of a RAID 5 or 6 and lose 
a drive?

Will the array be able to continue to reshape in a degraded state?

Hoping of course that this does not occur, but just trying to plan ahead 
in case.

Regards,
Brad

Reshaping appears to be much much slower.

I can resync in just a 2-3 hours, but a reshape of a single drive 
takes 10-15 hours with nothing else happening, if any other work is 
being done by the disks the number gets much worse.

To make it look just like a normally built array of the same number of 
disks it is very likely that reshaping is moving lots and lots of data 
around to make the changes.

I have so far done 2 reshapes, and I would like to know also how 
dangerous an event would be if it happens during a reshape.