I move my nextcloud user data to external USB drive but the DB was still on sd card.
I did not seen any read/write error on system log. So maybe my DB si not yet completly corrupted.
Here is the output of ls -l /var/lib/mysql/nextcloud/
-rw-rw---- 1 mysql mysql 67 Jan 14 2019 db.opt
-rw-rw---- 1 mysql mysql 1210 Jan 14 2019 oc_accounts.frm
-rw-rw---- 1 mysql mysql 65536 Feb 7 2019 oc_accounts.ibd
-rw-rw---- 1 mysql mysql 40517 Jan 14 2019 oc_activity.frm
-rw-rw---- 1 mysql mysql 90112 Feb 1 2019 oc_activity.ibd
-rw-rw---- 1 mysql mysql 23033 Jan 14 2019 oc_activity_mq.frm
-rw-rw---- 1 mysql mysql 73728 Jan 14 2019 oc_activity_mq.ibd
-rw-rw---- 1 mysql mysql 2557 Jan 14 2019 oc_addressbookchanges.frm
-rw-rw---- 1 mysql mysql 65536 Nov 6 08:06 oc_addressbookchanges.ibd
-rw-rw---- 1 mysql mysql 5643 Jan 14 2019 oc_addressbooks.frm
-rw-rw---- 1 mysql mysql 65536 Nov 6 08:06 oc_addressbooks.ibd
-rw-rw---- 1 mysql mysql 2354 Jan 14 2019 oc_appconfig.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 23:15 oc_appconfig.ibd
-rw-rw---- 1 mysql mysql 4670 Jan 14 2019 oc_authtoken.frm
-rw-rw---- 1 mysql mysql 188416 Nov 26 23:20 oc_authtoken.ibd
-rw-rw---- 1 mysql mysql 1001 Apr 11 2019 oc_bookmarks_folders_bookmarks.frm
-rw-rw---- 1 mysql mysql 131072 Apr 17 2019 oc_bookmarks_folders_bookmarks.ibd
-rw-rw---- 1 mysql mysql 18177 Apr 11 2019 oc_bookmarks_folders.frm
-rw-rw---- 1 mysql mysql 65536 Apr 11 2019 oc_bookmarks_folders.ibd
-rw-rw---- 1 mysql mysql 51048 Apr 11 2019 oc_bookmarks.frm
-rw-rw---- 1 mysql mysql 204800 Apr 17 2019 oc_bookmarks.ibd
-rw-rw---- 1 mysql mysql 1978 Feb 1 2019 oc_bookmarks_tags.frm
-rw-rw---- 1 mysql mysql 65536 Apr 17 2019 oc_bookmarks_tags.ibd
-rw-rw---- 1 mysql mysql 5351 Jan 14 2019 oc_bruteforce_attempts.frm
-rw-rw---- 1 mysql mysql 65536 Nov 21 03:57 oc_bruteforce_attempts.ibd
-rw-rw---- 1 mysql mysql 2588 Jan 14 2019 oc_calendarchanges.frm
-rw-rw---- 1 mysql mysql 155648 Nov 24 11:11 oc_calendarchanges.ibd
-rw-rw---- 1 mysql mysql 5941 Jan 14 2019 oc_calendar_invitations.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_calendar_invitations.ibd
-rw-rw---- 1 mysql mysql 4008 Jan 14 2019 oc_calendarobjects.frm
-rw-rw---- 1 mysql mysql 6291456 Nov 24 11:11 oc_calendarobjects.ibd
-rw-rw---- 1 mysql mysql 4107 Jan 14 2019 oc_calendarobjects_props.frm
-rw-rw---- 1 mysql mysql 450560 Nov 24 11:11 oc_calendarobjects_props.ibd
-rw-rw---- 1 mysql mysql 21100 Jan 14 2019 oc_calendar_resources.frm
-rw-rw---- 1 mysql mysql 73728 Jan 14 2019 oc_calendar_resources.ibd
-rw-rw---- 1 mysql mysql 21100 Jan 14 2019 oc_calendar_rooms.frm
-rw-rw---- 1 mysql mysql 73728 Jan 14 2019 oc_calendar_rooms.ibd
-rw-rw---- 1 mysql mysql 7086 Jan 14 2019 oc_calendars.frm
-rw-rw---- 1 mysql mysql 65536 Nov 24 11:11 oc_calendars.ibd
-rw-rw---- 1 mysql mysql 5298 Jan 14 2019 oc_calendarsubscriptions.frm
-rw-rw---- 1 mysql mysql 65536 Nov 23 05:15 oc_calendarsubscriptions.ibd
-rw-rw---- 1 mysql mysql 3797 Aug 18 18:15 oc_cards.frm
-rw-rw---- 1 mysql mysql 5242880 Nov 6 08:06 oc_cards.ibd
-rw-rw---- 1 mysql mysql 4309 Aug 18 18:15 oc_cards_properties.frm
-rw-rw---- 1 mysql mysql 212992 Nov 6 08:06 oc_cards_properties.ibd
-rw-rw---- 1 mysql mysql 2799 Aug 18 18:12 oc_collres_accesscache.frm
-rw-rw---- 1 mysql mysql 73728 Nov 21 11:15 oc_collres_accesscache.ibd
-rw-rw---- 1 mysql mysql 1205 Aug 18 18:12 oc_collres_collections.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:12 oc_collres_collections.ibd
-rw-rw---- 1 mysql mysql 1512 Aug 18 18:12 oc_collres_resources.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:12 oc_collres_resources.ibd
-rw-rw---- 1 mysql mysql 4541 Jan 14 2019 oc_comments.frm
-rw-rw---- 1 mysql mysql 81920 Jan 14 2019 oc_comments.ibd
-rw-rw---- 1 mysql mysql 2280 Jan 14 2019 oc_comments_read_markers.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_comments_read_markers.ibd
-rw-rw---- 1 mysql mysql 1994 Jan 14 2019 oc_credentials.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 23:20 oc_credentials.ibd
-rw-rw---- 1 mysql mysql 4622 Jan 14 2019 oc_dav_shares.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_dav_shares.ibd
-rw-rw---- 1 mysql mysql 2520 Jan 14 2019 oc_directlink.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_directlink.ibd
-rw-rw---- 1 mysql mysql 2745 Feb 1 2019 oc_external_applicable.frm
-rw-rw---- 1 mysql mysql 73728 Nov 26 22:46 oc_external_applicable.ibd
-rw-rw---- 1 mysql mysql 18633 Feb 1 2019 oc_external_config.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 22:47 oc_external_config.ibd
-rw-rw---- 1 mysql mysql 2109 Feb 1 2019 oc_external_mounts.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 22:46 oc_external_mounts.ibd
-rw-rw---- 1 mysql mysql 3272 Feb 1 2019 oc_external_options.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 22:47 oc_external_options.ibd
-rw-rw---- 1 mysql mysql 988 Jan 14 2019 oc_federated_reshares.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_federated_reshares.ibd
-rw-rw---- 1 mysql mysql 22638 Jan 14 2019 oc_filecache.frm
-rw-rw---- 1 mysql mysql 12582912 Nov 26 23:20 oc_filecache.ibd
-rw-rw---- 1 mysql mysql 2233 Jan 14 2019 oc_file_locks.frm
-rw-rw---- 1 mysql mysql 65536 Apr 17 2019 oc_file_locks.ibd
-rw-rw---- 1 mysql mysql 6931 Jan 14 2019 oc_files_trash.frm
-rw-rw---- 1 mysql mysql 90112 Nov 20 15:44 oc_files_trash.ibd
-rw-rw---- 1 mysql mysql 2737 Jan 14 2019 oc_flow_checks.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_flow_checks.ibd
-rw-rw---- 1 mysql mysql 3094 Jan 14 2019 oc_flow_operations.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_flow_operations.ibd
-rw-rw---- 1 mysql mysql 1944 Jan 14 2019 oc_group_admin.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_group_admin.ibd
-rw-rw---- 1 mysql mysql 1176 Jan 14 2019 oc_groups.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_groups.ibd
-rw-rw---- 1 mysql mysql 1944 Jan 14 2019 oc_group_user.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_group_user.ibd
-rw-rw---- 1 mysql mysql 18625 Jan 14 2019 oc_jobs.frm
-rw-rw---- 1 mysql mysql 73728 Nov 26 23:20 oc_jobs.ibd
-rw-rw---- 1 mysql mysql 11908 Aug 18 18:12 oc_login_flow_v2.frm
-rw-rw---- 1 mysql mysql 73728 Aug 18 18:12 oc_login_flow_v2.ibd
-rw-rw---- 1 mysql mysql 2987 Jan 14 2019 oc_migrations.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:14 oc_migrations.ibd
-rw-rw---- 1 mysql mysql 2462 Jan 14 2019 oc_mimetypes.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 21:40 oc_mimetypes.ibd
-rw-rw---- 1 mysql mysql 19776 Jan 14 2019 oc_mounts.frm
-rw-rw---- 1 mysql mysql 90112 Nov 26 22:45 oc_mounts.ibd
-rw-rw---- 1 mysql mysql 4118 Jan 14 2019 oc_news_feeds.frm
-rw-rw---- 1 mysql mysql 81920 Jan 14 2019 oc_news_feeds.ibd
-rw-rw---- 1 mysql mysql 3235 Jan 14 2019 oc_news_folders.frm
-rw-rw---- 1 mysql mysql 73728 Jan 14 2019 oc_news_folders.ibd
-rw-rw---- 1 mysql mysql 3907 Jan 14 2019 oc_news_items.frm
-rw-rw---- 1 mysql mysql 81920 Jan 14 2019 oc_news_items.ibd
-rw-rw---- 1 mysql mysql 2884 Jan 14 2019 oc_notes_meta.frm
-rw-rw---- 1 mysql mysql 73728 Jan 14 2019 oc_notes_meta.ibd
-rw-rw---- 1 mysql mysql 36671 Jan 14 2019 oc_notifications.frm
-rw-rw---- 1 mysql mysql 114688 Nov 26 21:29 oc_notifications.ibd
-rw-rw---- 1 mysql mysql 6139 Jan 14 2019 oc_notifications_pushtokens.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_notifications_pushtokens.ibd
-rw-rw---- 1 mysql mysql 5682 Jan 14 2019 oc_oauth2_access_tokens.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_oauth2_access_tokens.ibd
-rw-rw---- 1 mysql mysql 10297 Aug 18 18:13 oc_oauth2_clients.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:13 oc_oauth2_clients.ibd
-rw-rw---- 1 mysql mysql 1658 Jan 14 2019 oc_preferences.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 22:49 oc_preferences.ibd
-rw-rw---- 1 mysql mysql 1997 Jan 14 2019 oc_preview_generation.frm
-rw-rw---- 1 mysql mysql 81920 Nov 26 20:45 oc_preview_generation.ibd
-rw-rw---- 1 mysql mysql 1208 Aug 18 18:14 oc_privacy_admins.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:14 oc_privacy_admins.ibd
-rw-rw---- 1 mysql mysql 3843 Jan 14 2019 oc_properties.frm
-rw-rw---- 1 mysql mysql 65536 Mar 27 2019 oc_properties.ibd
-rw-rw---- 1 mysql mysql 3278 Jan 14 2019 oc_schedulingobjects.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_schedulingobjects.ibd
-rw-rw---- 1 mysql mysql 21979 Jan 14 2019 oc_share_external.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_share_external.ibd
-rw-rw---- 1 mysql mysql 13324 Jan 14 2019 oc_share.frm
-rw-rw---- 1 mysql mysql 106496 Nov 21 11:15 oc_share.ibd
-rw-rw---- 1 mysql mysql 1766 Jan 14 2019 oc_storages.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 22:47 oc_storages.ibd
-rw-rw---- 1 mysql mysql 1752 Jan 14 2019 oc_systemtag.frm
-rw-rw---- 1 mysql mysql 1977 Jan 14 2019 oc_systemtag_group.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_systemtag_group.ibd
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_systemtag.ibd
-rw-rw---- 1 mysql mysql 1504 Jan 14 2019 oc_systemtag_object_mapping.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_systemtag_object_mapping.ibd
-rw-rw---- 1 mysql mysql 8416 Jan 14 2019 oc_trusted_servers.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_trusted_servers.ibd
-rw-rw---- 1 mysql mysql 2257 Jan 14 2019 oc_twofactor_backupcodes.frm
-rw-rw---- 1 mysql mysql 65536 Feb 1 2019 oc_twofactor_backupcodes.ibd
-rw-rw---- 1 mysql mysql 1850 Aug 18 18:15 oc_twofactor_providers.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:15 oc_twofactor_providers.ibd
-rw-rw---- 1 mysql mysql 1794 Aug 18 18:13 oc_twofactor_totp_secrets.frm
-rw-rw---- 1 mysql mysql 65536 Nov 26 22:45 oc_twofactor_totp_secrets.ibd
-rw-rw---- 1 mysql mysql 3286 Jan 14 2019 oc_users.frm
-rw-rw---- 1 mysql mysql 65536 Feb 1 2019 oc_users.ibd
-rw-rw---- 1 mysql mysql 3999 Jan 14 2019 oc_vcategory.frm
-rw-rw---- 1 mysql mysql 73728 Jan 14 2019 oc_vcategory.ibd
-rw-rw---- 1 mysql mysql 1733 Jan 14 2019 oc_vcategory_to_object.frm
-rw-rw---- 1 mysql mysql 65536 Jan 14 2019 oc_vcategory_to_object.ibd
-rw-rw---- 1 mysql mysql 2528 Aug 18 18:15 oc_whats_new.frm
-rw-rw---- 1 mysql mysql 65536 Aug 18 18:15 oc_whats_new.ibd```
Do you have any advise or howto use recovery mode ?