LXD does not start after a storage pool was accidentally deleted

LXD
2

I could resolve this issue by myself.

According to the lxd database documentation, it seems that I could delete unnecessary settings at startup by putting a patch.global.sql under /var/snap/lxd/common/lxd/database with query to delete old setting records.

So I confirmed the unnecessary records by

$ sqlite3 /var/snap/lxd/common/lxd/database/global/db.bin
sqlite> select * from storage_pools;
...
sqlite> select * from storage_pools_config;
...

and created a query to delete those records.