[dm-crypt] Device $dev is not a valid LUKS device.

[Erik Logtenberg <erik@logtenberg.eu>]

Hi all,

I've been using dm-crypt for quite some years now, and every now and
then I am very unpleasantly surprised by the message that my entire
volume can no longer be read:

Device /dev/disk/by-path/ip-foo.bar:mainstorage-lun-1 is not a valid
LUKS device.

In this case the iscsi server was rebooted while the volume was still
mounted. The volume is used for making backups and no backups were
currently made, so no actual writes got lost. Nevertheless after reboot
it no longer recognizes my luks volume.

I've had this kind of malice before and at that time was unable to fix
it. So in the end I gave up, created a new luks volume and started from
scratch.

However I hope that is not how every future power failure is going to
end up. Is there anything I can do to fix this volume or anything I can
do to prevent such a simple event from causing such catastrophic results?

Kind regards,

Erik.