after adding one more physical volume and enlarging logical volume, grub fails

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http://unix.stackexchange.com – Several years ago I installed Debian on my 500 GiB hard disk. During installation I chose to have encrypted filesystem. So installer created one small unencrypted boot partition (I guess that grub configuration is kept there) and one large LUKS encrypted partition. This large encrypted partition is a physical volume, which is the only member of a volume group, on which two logical volumes are created - one for swap and one for everything else. And everything was working fine in this configuration for several years without me thinking too much about it. Few days ago I bought new 2 TiB hard dri (HowTos)