[knot-dns-users] restore, key copy failed (already exists)

Hi, In our setup, we have one active signer and one backup signer. Both use softhsm, but only the active signer does automatic key management. There is an hourly cron job that syncs keys from active to backup signer. It runs knotc zone-backup on the active signer, only backing up the kaspdb. It then syncs the files over to the secondary and runs knotc zone-restore. This has been running for a few years now without problems. These last two weeks we’ve been performing algorithm rollovers for some of our zones, and after we run `knotc zone-ksk-submitted nic.is` we start seeing these errors when the zone-restore is run on the backup: error: [nic.is.] zone event 'backup/restore' failed (already exists) warning: [nic.is.] zone restore failed (already exists) warning: [nic.is.] restore, key copy failed (already exists) I searched the knot dns source code, but couldn't find where these errors are output. Like I said, we’ve been running like this for a few years, doing regular ZSK rollovers, and a few KSK rollovers, without problems. There’s something about the algorithm rollover that causes this problem with our setup. I assume I can just delete the keys on the secondary and sync again, but I want to understand what causes these errors so we can avoid them or at best document them in our process. .einar