On Fri, 2022-11-18 at 22:03 -0500, Steve Litt wrote:
> Peter Duffy said on Fri, 18 Nov 2022 15:25:40 +0000
>
> > I recently bought a couple of Samsung 1T EVO 970 SSDs to do some
> > work:
> > basically I need to simulate the loading of a fairly big mysql
> > database
> > (>80G). I'm currently hitting a very weird problem. 
> >
> > The mysql is percona 5.7. I attach the disk via USB3, partition it,
> > create an ext4 fs on one of the partitions, mount it, create a
> > directory on it, configure mysql to use it as the datadir, and then
> > initialise it for mysql use. All good so far. I then start the
> > mysql
> > dataload, and it's progressing happily. 
> >
> > Then the mysql server bombs out, and messages like the following
> > appear
> > in the dmesg output:
>
> [snip hard to read error message]
>
> >
> > I'm trying to decide whether I'm just dealing with a borked SSD (it
> > came from Amazon: yeah, I know
>
> I'm no bezos lover, but you tested the drive and it tested OK. Sounds
> to me like a plain old MySQL error. I'm not sure how the cryptic
> error
> message points an accusing finger at your desk.
>
> If for some reason you suspect gremlins outside of MySQL and its
> config
> files, tonight as you go to sleep why not run a memtest86 on your
> ram.
> This should be done every couple months anyway, and it will
> (hopefully)
> rule out faulty ram locations.
>

I've just posted an update. I tried attaching the disk directly via
SATA - after this, the mysql data load apparently completed without a
problem. This box was intended as a mysql slave: after the load, I was
able to configure the slave setup and start the slave threads - and
replication started and kept going. (Mysql replication tends to stop
and wait for human intervention at the first sign of trouble - so if it
works OK over a reasonable period of time, it's usually a sign that the
database is in good shape.)

It's looking as though the problem might be related to UAS - at some
point, I'm going to try attaching the disk via USB3 again, and disable
UAS (once I figure out how to do it) and see what happens.