Problem solved! My usual problem of missing the detail...
I'd described starting with a 2-drive mirror and converting it to a
3-drive raid-5. I was actually starting with a 2-active-1-spare mirror ...
Cheers,
Wol
On 28/11/2021 09:25, Wols Lists wrote:
Finally upgrading my system to raid-5 - two Seagate Ironwolves and a
Barracuda ... :-(
As per my own advice, I added the third drive as a spare, then grew the
array to raid-5 in two separate commands.
Trying to track what's going on, "cat /proc/mdstat" just shows two
drives as sync'ing. "mdadm --detail" shows two active drives and a spare.
The drives are quite clearly working away - as I would expect.
So. What I *think* is happening is that my mirror is upgrading to a
2-disk raid-5, and when that's finished it will add the spare and
upgrade to a full 3-disk raid-5. Does that sound right?
What I *hoped* would happen (and thought *should* happen) was that it
would spot the third drive, add it, and just resync straight away to
full raid-5.
So at 7 or 8hrs per pass (3TB per drive) I'm now looking at my upgrade
taking about 15 hours. Whoops.
So basically, does my scenario sound right? Would have explicitly
changing raid-devices to 3 at the same time as converting to raid-5
improved matters?
Okay, I'm going to build a new raid-testing computer in the near future
so testing this sort of thing will be easy, but that is predicated on me
finding enough time without upsetting the wife ...
Cheers,
Wol
