> I've had this happen maybe a dozen times over the years and I wonder if
> anyone knows what I'm doing to cause it.
Seeing the hordes rushing to drown you in suggestions, I'll take
my chance. Based on what you say, I suspect I won't tell you anything
you don't already know, tho. 🙁
> I reboot and grub fails to find anything. ls shows memdisk and the main disk
> but nothing else. insmod lvm etc makes no difference at all.
>
> But once you run pvresize on the PV, grub is happy again and finds
> everything it needs to boot.
- I suspect you might get better info from Grub insiders.
Maybe it's worth opening a bug report, even if you don't have much
concrete data to provide, in the hope to get them to tell you how you
might collect useful data next time it happens.
- Maybe something corrupts some copy of the LVM info, which is the one
Grub uses, whereas `pvresize` is able to read some other copy and
silently refresh/fix the corrupted copy?
- My crystal ball is terribly hazy, but it suggests maybe some problem
in the disk makes it occasionally "fail to start up", or rather
startup in such a way that when Grub tries to get the LVM info it gets
some kind of error, even though it would succeed if it were done
a fraction of a second later.
That would be fundamentally unrelated to LVM, so I'd expect it to show
up in other ways as well, but maybe in your context there's nothing else
to affect. Running `pvresize` would simply have the effect of
slightly changing the disk's erroneous behavior.
[ E.g. maybe the problem is when the disk is shutdown in a particular
way, it takes more time to boot (e.g. because it has to work harder
to recover its "logical-to-physical block mapping", assuming it's
an SSD). ]
The last two ideas are *very* hypothetical.
=== Stefan
