Re: Horrendous RAIDframe reconstruction performance

[Greg Oster <oster%netbsd.org@localhost>]

On 6/28/20 7:31 PM, John Klos wrote:
> > Any thoughts about what's going on here? Is this because the drives 
> > are 512e drives? Three weeks is a LONG time to reconstruct.
>
> So this turns out to be a failing drive. SMART doesn't show it's 
> failing, but the one that's failing defaults to having the write cache 
> off, and turning it on doesn't change the speed.

Yep, that will do it.

> I guess it's still usable, in a limited way - I can only write at 5 or 6 
> MB/sec, but I can read at 200 MB/sec. Maybe I'll use it in an m68k Mac.
>
> Also, the autoconfigure works, but the forcing of root FS status didn't 
> because I was testing it on a system that already had a RAIDframe with 
> forced root. However, it still doesn't work on aarch64, but I'll recheck 
> this after trying Jared's boot.cfg support.
>
> Thanks, Greg, Michael and Edgar. I learned something :) I am still 
> curious about whether I was seeing both good read and write speeds 
> because writes weren't going to both drives. I suppose I assumed that 
> all writes would go to both drives even while reconstructing, but I 
> suppose that only happens when the writes are inside of the area which 
> has already been reconstructed, yes?

Correct.  Writes will go to both on stripes where reconstruction has 
completed, but will only go to the 'good' device if reconstruction 
hasn't reached that stripe yet.

Later...

Greg Oster