The server backs itself up: every collection byte for byte, the media linked

A backup is a directory <stamp>-<kind> under Backups:Root (/var/lib/privapub/backups, 2770, files 0640), written as
.partial and renamed once whole: a manifest (host, build, newest migration, each collection's count, size, sha256 and
indexes, what was left out and why, the media list), each collection as gzipped canonical Extended JSON read raw, and
hard links to the files of untrashed media rows (copies where a link can't be made). On a replica set every collection
is read in one snapshot session. Never in a backup: the statistics salt, jobs, recovery codes, sessions, the
maintenance lock and the configuration's copy with its SMTP password.

One backup or restore at a time (MaintenanceLock, a heartbeat document), and the janitor purges nothing meanwhile.
BackupScheduler backs up nightly at 03:30 UTC (or at once after missing a night); rotation keeps 7 daily, 4 weekly,
3 pre-deploy and 3 pre-restore backups. CLI: admin backup [--kind] [--db-only], admin backups, admin backup verify;
these run before migrations, so the deploy's own pre-deploy backup, which replaces mongodump, is of the database as the
live build left it. EntityMaps.Warm runs once under a lock, since test hosts now boot side by side.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

PrivaPub/Domain/Media/MediaProxy.cs

@@ -361,7 +361,8 @@ namespace PrivaPub.Domain.Media
 		// one pass:
 		// - uploads never posted for a day (and not waiting for a scheduled post, nor a profile picture) go to the trash;
 		// - trashed files still served (a crash between the mark and the move) are moved out;
-		// - trashed files past their grace are deleted, with their rows;
+		// - trashed files past their grace are deleted, with their rows, unless a backup or a restore is running (one may be
+		//   reading the trash);
 		// - the proxy cache is trimmed to its size, oldest first
 		public async Task Sweep(CancellationToken token)
 		{
@@ -371,10 +372,11 @@ namespace PrivaPub.Domain.Media
 
 			var trashed = await DB.Default.Find<MediaAttachment>().Match(m => m.TrashedAt != null).Limit(2000).ExecuteAsync(token);
 			var purgeBefore = DateTime.UtcNow - TrashGrace;
+			var maintenance = await Infrastructure.Backup.MaintenanceLock.Current(token) != default;
 			var purged = 0;
 			foreach (var row in trashed)
 			{
-				if (row.TrashedAt < purgeBefore)
+				if (row.TrashedAt < purgeBefore && !maintenance)
 				{
 					await _media.Purge(row, token);
 					purged++;