diff --git a/bin/builder_db_app.ml b/bin/builder_db_app.ml
index 10ff322..99d9923 100644
--- a/bin/builder_db_app.ml
+++ b/bin/builder_db_app.ml
@@ -16,6 +16,13 @@ let defer_foreign_keys =
   Caqti_type.unit ->. Caqti_type.unit @@
   "PRAGMA defer_foreign_keys = ON"
 
+let build_artifacts_to_orphan =
+  Builder_db.Rep.id `build ->* Builder_db.Rep.cstruct @@
+  {| SELECT a.sha256 FROM build_artifact a
+     WHERE a.build = ? AND
+           (SELECT COUNT(*) FROM build_artifact a2
+            WHERE a2.sha256 = a.sha256 AND a2.build <> a.build) = 0 |}
+
 let connect uri =
   let* (module Db : Caqti_blocking.CONNECTION) = Caqti_blocking.connect ~tweaks_version:(1,8) uri in
   let* () = Db.exec defer_foreign_keys () in
@@ -36,6 +43,16 @@ let do_migrate dbpath =
 let migrate () dbpath =
   or_die 1 (do_migrate dbpath)
 
+let artifacts_dir datadir = Fpath.(datadir / "_artifacts")
+let artifact_path sha256 =
+  let (`Hex sha256) = Hex.of_cstruct sha256 in
+  (* NOTE: [sha256] is 64 characters when it's a hex sha256 checksum *)
+  (* NOTE: We add the prefix to reduce the number of files in a directory - a
+     workaround for inferior filesystems. We can easily revert this by changing
+     this function and adding a migration. *)
+  let prefix = String.sub sha256 0 2 in
+  Fpath.(v "_artifacts" / prefix / sha256)
+
 let user_mod action dbpath scrypt_n scrypt_r scrypt_p username unrestricted =
   let scrypt_params = Builder_web_auth.scrypt_params ?scrypt_n ?scrypt_r ?scrypt_p () in
   let r =
@@ -154,6 +171,18 @@ let job_remove () datadir jobname =
               (match Bos.OS.Dir.delete ~recurse:true dir with
                | Ok _ -> ()
                | Error `Msg e -> Logs.warn (fun m -> m "failed to remove build directory %a: %s" Fpath.pp dir e));
+              let* () =
+                Db.iter_s build_artifacts_to_orphan
+                  (fun sha256 ->
+                     let p = Fpath.(v datadir // artifact_path sha256) in
+                     match Bos.OS.Path.delete p with
+                     | Ok () -> Ok ()
+                     | Error `Msg e ->
+                       Logs.warn (fun m -> m "failed to remove orphan artifact %a: %s"
+                                     Fpath.pp p e);
+                       Ok ())
+                  build_id
+              in
               let* () = Db.exec Builder_db.Build_artifact.remove_by_build build_id in
               Db.exec Builder_db.Build.remove build_id)
             (Ok ())
@@ -214,12 +243,12 @@ let num_build_artifacts =
   Caqti_type.unit ->! Caqti_type.int @@
   "SELECT count(*) FROM build_artifact"
 
-let build_artifacts : (unit, string * Uuidm.t * (Fpath.t * Fpath.t * Cstruct.t * int64), [ `One | `Zero | `Many ]) Caqti_request.t =
+let build_artifacts : (unit, string * Uuidm.t * (Fpath.t * Cstruct.t * int64), [ `One | `Zero | `Many ]) Caqti_request.t =
   Caqti_type.unit ->*
   Caqti_type.(tup3 string Builder_db.Rep.uuid
-                (tup4 Builder_db.Rep.fpath Builder_db.Rep.fpath Builder_db.Rep.cstruct int64))
+                (tup3 Builder_db.Rep.fpath Builder_db.Rep.cstruct int64))
   @@
-  {| SELECT job.name, b.uuid, a.filepath, a.localpath, a.sha256, a.size
+  {| SELECT job.name, b.uuid, a.filepath, a.sha256, a.size
      FROM build_artifact a, build b, job
      WHERE a.build = b.id AND b.job = job.id |}
 
@@ -257,36 +286,33 @@ let verify_data_dir () datadir =
       let idx = ref 0 in
       fun () -> incr idx; if !idx mod 100 = 0 then Logs.info (fun m -> m "%d" !idx);
     in
-    let verify_job_and_uuid ?fpath job uuid path =
+    let verify_job_and_uuid job uuid path =
       match Fpath.segs path with
-      | job' :: uuid' :: tl ->
+      | job' :: uuid' :: _tl ->
         if String.equal job job' then () else Logs.warn (fun m -> m "job names do not match: %s vs %s" job job');
         if String.equal (Uuidm.to_string uuid) uuid' then () else Logs.warn (fun m -> m "uuid does not match: %s vs %s" (Uuidm.to_string uuid) uuid');
-        (match fpath, tl with
-         | None, _ -> ()
-         | Some f, "output" :: tl ->
-           if Fpath.equal (Fpath.v (String.concat "/" tl)) f then
-            ()
-           else
-            Logs.err (fun m -> m "path (%a) and fpath (%a) do not match" Fpath.pp path Fpath.pp f)
-         | Some _, _ ->
-           Logs.err (fun m -> m "path is not of form <job>/<uuid>/output/<filename>: %a" Fpath.pp path))
       | _ -> Logs.err (fun m -> m "path is not of form <job>/<uuid>/...: %a" Fpath.pp path)
     in
     let* () =
-      Db.iter_s build_artifacts (fun (job, uuid, (fpath, lpath, sha, size)) ->
+      Db.iter_s build_artifacts (fun (_job, _uuid, (_fpath, sha256, size)) ->
           progress ();
-          verify_job_and_uuid ~fpath job uuid lpath;
-          let abs_path = Fpath.(v datadir // lpath) in
-          (match Bos.OS.File.read abs_path with
-           | Error (`Msg msg) -> Logs.err (fun m -> m "file %a not present: %s" Fpath.pp abs_path msg)
-           | Ok data ->
-             files_tracked := FpathSet.add lpath !files_tracked;
-             let s = Int64.of_int (String.length data) in
-             if s <> size then Logs.err (fun m -> m "File %a has different size (in DB %Lu on disk %Lu)" Fpath.pp abs_path size s);
-             let sh = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data) in
-             if not (Cstruct.equal sha sh) then Logs.err (fun m -> m "File %a has different hash (in DB %a on disk %a" Fpath.pp abs_path Cstruct.hexdump_pp sha Cstruct.hexdump_pp sh)) ;
-          Ok ()
+          if not (FpathSet.mem (artifact_path sha256) !files_tracked) then
+            let abs_path = Fpath.(v datadir // artifact_path sha256) in
+            (match Bos.OS.File.read abs_path with
+             | Error (`Msg msg) -> Logs.err (fun m -> m "file %a not present: %s" Fpath.pp abs_path msg)
+             | Ok data ->
+               files_tracked := FpathSet.add (artifact_path sha256) !files_tracked;
+               let s = Int64.of_int (String.length data) in
+               if s <> size then Logs.err (fun m -> m "File %a has different size (in DB %Lu on disk %Lu)" Fpath.pp abs_path size s);
+               let sha256' = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data) in
+               if not (Cstruct.equal sha256 sha256') then
+                 Logs.err (fun m -> m "File %a has different hash (in DB %a on disk %a)"
+                              Fpath.pp abs_path
+                              Hex.pp (Hex.of_cstruct sha256)
+                              Hex.pp (Hex.of_cstruct sha256'))) ;
+            Ok ()
+          else
+            Ok ()
         ) ()
     in
     Db.iter_s script_and_console (fun (job, uuid, console, script) ->
@@ -460,7 +486,7 @@ module Verify_cache_dir = struct
         AND ba_opam_switch.filepath = 'opam-switch'
       LEFT JOIN build_artifact AS ba_debug_bin ON
         ba_debug_bin.build = b.id
-        AND ba_debug_bin.localpath LIKE '%.debug'
+        AND ba_debug_bin.filepath LIKE '%.debug'
     |}
 
   let check_viz_nonempty ~cachedir ~viz_typ ~hash =
@@ -681,9 +707,9 @@ let extract_full () datadir dest uuid =
     let out = console_of_string console in
     let* artifacts = Db.collect_list Builder_db.Build_artifact.get_all_by_build build_id in
     let* data =
-      List.fold_left (fun acc (_, { Builder_db.filepath; localpath; _ }) ->
+      List.fold_left (fun acc (_, { Builder_db.filepath; sha256; _ }) ->
           let* acc = acc in
-          let* data = Bos.OS.File.read Fpath.(v datadir // localpath) in
+          let* data = Bos.OS.File.read Fpath.(v datadir // artifact_path sha256) in
           Ok ((filepath, data) :: acc))
         (Ok [])
         artifacts
diff --git a/bin/migrations/builder_migrations.ml b/bin/migrations/builder_migrations.ml
index 862ffd3..ae84f6f 100644
--- a/bin/migrations/builder_migrations.ml
+++ b/bin/migrations/builder_migrations.ml
@@ -180,6 +180,7 @@ let () =
         actions (module M20211105);
         actions (module M20220509);
         actions (module M20230911);
+        actions (module M20230914);
       ])
   |> Cmd.eval
   |> exit
diff --git a/bin/migrations/m20230914.ml b/bin/migrations/m20230914.ml
new file mode 100644
index 0000000..e1b79db
--- /dev/null
+++ b/bin/migrations/m20230914.ml
@@ -0,0 +1,162 @@
+let new_version = 18L and old_version = 17L
+and identifier = "2023-09-14"
+and migrate_doc = "Artifacts are stored content-addressed in the filesystem"
+and rollback_doc = "Artifacts are stored under their build's job name and uuid"
+
+open Grej.Syntax
+
+let new_build_artifact =
+  Caqti_type.unit ->. Caqti_type.unit @@
+  {| CREATE TABLE new_build_artifact (
+         id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+         filepath TEXT NOT NULL,
+         sha256 BLOB NOT NULL,
+         size INTEGER NOT NULL,
+         build INTEGER NOT NULL,
+
+         FOREIGN KEY(build) REFERENCES build(id),
+         UNIQUE(build, filepath)
+       )
+  |}
+
+let old_build_artifact =
+  Caqti_type.unit ->.  Caqti_type.unit @@
+  {| CREATE TABLE new_build_artifact (
+         id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+         filepath TEXT NOT NULL, -- the path as in the build
+         localpath TEXT NOT NULL, -- local path to the file on disk
+         sha256 BLOB NOT NULL,
+         size INTEGER NOT NULL,
+         build INTEGER NOT NULL,
+
+         FOREIGN KEY(build) REFERENCES build(id),
+         UNIQUE(build, filepath)
+       )
+  |}
+
+let idx_build_artifact_sha256 =
+  Caqti_type.unit ->. Caqti_type.unit @@
+  "CREATE INDEX idx_build_artifact_sha256 ON build_artifact(sha256)"
+
+let idx_build_artifact_build =
+  Caqti_type.unit ->. Caqti_type.unit @@
+  "CREATE INDEX idx_build_artifact_build ON build_artifact(build)"
+
+let copy_new_build_artifact =
+  Caqti_type.(unit ->. unit) @@
+  {| INSERT INTO new_build_artifact(id, filepath, sha256, size, build)
+     SELECT id, filepath, sha256, size, build
+     FROM build_artifact
+  |}
+
+let copy_old_build_artifact =
+  Caqti_type.(unit ->. unit) @@
+  {| INSERT INTO new_build_artifact(id, filepath, localpath, sha256, size, build)
+     SELECT a.id, a.filepath,
+       j.name || '/' || b.uuid || '/output/' || a.filepath,
+       a.sha256, a.size, a.build
+     FROM build_artifact a, job j, build b
+     WHERE b.id = a.build AND j.id = b.job
+  |}
+
+let new_build_artifact_paths =
+  Caqti_type.unit ->* Caqti_type.(tup2 string string) @@
+  {| SELECT localpath, '_artifacts/' || substr(lower(hex(sha256)), 1, 2) || '/' || lower(hex(sha256))
+     FROM build_artifact
+  |}
+
+let old_build_artifact_paths =
+  Caqti_type.unit ->* Caqti_type.(tup2 string string) @@
+  {| SELECT '_artifacts/' || substr(lower(hex(a.sha256)), 1, 2) || '/' || lower(hex(a.sha256)),
+       j.name || '/' || b.uuid || '/output/' || a.filepath
+     FROM build_artifact a, job j, build b
+     WHERE b.id = a.build AND j.id = b.job
+  |}
+
+let drop_build_artifact =
+  Caqti_type.(unit ->. unit) @@
+  "DROP TABLE build_artifact"
+
+let rename_build_artifact =
+  Caqti_type.(unit ->. unit) @@
+  "ALTER TABLE new_build_artifact RENAME TO build_artifact"
+
+let move_paths ?force datadir (old_path, new_path) =
+  let old_path = Fpath.(datadir // v old_path) and new_path = Fpath.(datadir // v new_path) in
+  let* _created = Bos.OS.Dir.create (Fpath.parent new_path) in
+  Bos.OS.Path.move ?force old_path new_path
+
+let copy_paths datadir (old_path, new_path) =
+  let old_path = Fpath.(datadir // v old_path) and new_path = Fpath.(datadir // v new_path) in
+  let new_path_tmp = Fpath.(new_path + "tmp") in
+  let* _created = Bos.OS.Dir.create (Fpath.parent new_path) in
+  let cmd = Bos.Cmd.(v "cp" % p old_path % p new_path_tmp) in
+  let* () =
+    match Bos.OS.Cmd.run_status cmd with
+    | Ok `Exited 0 ->
+      Ok ()
+    | Ok status ->
+      let _ = Bos.OS.Path.delete new_path_tmp in
+      Error (`Msg (Fmt.str "cp failed: %a" Bos.OS.Cmd.pp_status status))
+    | Error _ as e ->
+      let _ = Bos.OS.Path.delete new_path_tmp in
+      e
+  in
+  Bos.OS.Path.move ~force:true new_path_tmp new_path
+
+let migrate datadir (module Db : Caqti_blocking.CONNECTION) =
+  let* () = Grej.check_version ~user_version:old_version (module Db) in
+  let* () = Db.exec new_build_artifact () in
+  let* () = Db.exec copy_new_build_artifact () in
+  let* () = Db.iter_s new_build_artifact_paths (move_paths ~force:true datadir) () in
+  let* () = Db.exec drop_build_artifact () in
+  let* () = Db.exec rename_build_artifact () in
+  let* () = Db.exec idx_build_artifact_sha256 () in
+  let* () = Db.exec idx_build_artifact_build () in
+  Db.exec (Grej.set_version new_version) ()
+
+let rollback datadir (module Db : Caqti_blocking.CONNECTION) =
+  let* () = Grej.check_version ~user_version:new_version (module Db) in
+  let* () = Db.exec old_build_artifact () in
+  let* () = Db.exec copy_old_build_artifact () in
+  let* () = Db.iter_s old_build_artifact_paths (copy_paths datadir) () in
+  let* () =
+    Db.iter_s old_build_artifact_paths
+      (fun (old_path, _new_path) ->
+         Bos.OS.Path.delete Fpath.(datadir // v old_path))
+      ()
+  in
+  let* () = Db.exec drop_build_artifact () in
+  let* () = Db.exec rename_build_artifact () in
+  let* () = Db.exec idx_build_artifact_sha256 () in
+  Db.exec (Grej.set_version old_version) ()
+
+(* migration failed but managed to move *some* files *)
+let fixup_migrate datadir (module Db : Caqti_blocking.CONNECTION) =
+  let* () = Grej.check_version ~user_version:old_version (module Db) in
+  let* () =
+    Db.iter_s new_build_artifact_paths
+      (fun (old_path, new_path) ->
+         let* old_exists = Bos.OS.Path.exists Fpath.(datadir // v old_path) in
+         let* new_exists = Bos.OS.Path.exists Fpath.(datadir // v new_path) in
+         if new_exists && not old_exists then
+           copy_paths datadir (new_path, old_path)
+         else Ok ())
+      ()
+  in
+  Db.iter_s new_build_artifact_paths
+    (fun (_old_path, new_path) ->
+       Bos.OS.Path.delete Fpath.(datadir // v new_path))
+    ()
+
+(* rollback failed but some or all artifacts were copied *)
+let fixup_rollback datadir (module Db : Caqti_blocking.CONNECTION) =
+  let* () = Grej.check_version ~user_version:new_version (module Db) in
+  Db.iter_s old_build_artifact_paths
+    (fun (old_path, new_path) ->
+       let* old_exists = Bos.OS.Path.exists Fpath.(datadir // v old_path) in
+       if old_exists then
+         Bos.OS.Path.delete Fpath.(datadir // v new_path)
+       else
+         move_paths datadir (new_path, old_path))
+    ()
diff --git a/db/builder_db.ml b/db/builder_db.ml
index cdcd190..226f2b9 100644
--- a/db/builder_db.ml
+++ b/db/builder_db.ml
@@ -11,7 +11,6 @@ type 'a id = 'a Rep.id
 
 type file = Rep.file = {
   filepath : Fpath.t;
-  localpath : Fpath.t;
   sha256 : Cstruct.t;
   size : int;
 }
@@ -140,7 +139,6 @@ module Build_artifact = struct
     {| CREATE TABLE build_artifact (
            id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
            filepath TEXT NOT NULL, -- the path as in the build
-           localpath TEXT NOT NULL, -- local path to the file on disk
            sha256 BLOB NOT NULL,
            size INTEGER NOT NULL,
            build INTEGER NOT NULL,
@@ -156,13 +154,13 @@ module Build_artifact = struct
 
   let get =
     id `build_artifact ->! file @@
-    {| SELECT filepath, localpath, sha256, size
+    {| SELECT filepath, sha256, size
        FROM build_artifact WHERE id = ? |}
 
   let get_by_build_uuid =
     Caqti_type.tup2 uuid fpath ->? Caqti_type.tup2 (id `build_artifact) file @@
     {| SELECT build_artifact.id, build_artifact.filepath,
-         build_artifact.localpath, build_artifact.sha256, build_artifact.size
+         build_artifact.sha256, build_artifact.size
        FROM build_artifact
        INNER JOIN build ON build.id = build_artifact.build
        WHERE build.uuid = ? AND build_artifact.filepath = ?
@@ -170,12 +168,16 @@ module Build_artifact = struct
 
   let get_all_by_build =
     id `build ->* Caqti_type.(tup2 (id `build_artifact) file) @@
-    "SELECT id, filepath, localpath, sha256, size FROM build_artifact WHERE build = ?"
+    "SELECT id, filepath, sha256, size FROM build_artifact WHERE build = ?"
+
+  let exists =
+    cstruct ->! Caqti_type.bool @@
+    "SELECT EXISTS(SELECT 1 FROM build_artifact WHERE sha256 = ?)"
 
   let add =
     Caqti_type.(tup2 file (id `build)) ->. Caqti_type.unit @@
-    "INSERT INTO build_artifact (filepath, localpath, sha256, size, build) \
-     VALUES (?, ?, ?, ?, ?)"
+    "INSERT INTO build_artifact (filepath, sha256, size, build) \
+     VALUES (?, ?, ?, ?)"
 
   let remove_by_build =
     id `build ->. Caqti_type.unit @@
@@ -316,7 +318,7 @@ module Build = struct
          b.uuid, b.start_d, b.start_ps, b.finish_d, b.finish_ps,
          b.result_code, b.result_msg, b.console, b.script,
          b.platform, b.main_binary, b.input_id, b.user, b.job,
-         a.filepath, a.localpath, a.sha256, a.size
+         a.filepath, a.sha256, a.size
        FROM build b, build_artifact a
        WHERE b.main_binary = a.id AND b.job = $1 AND b.platform = $2
          AND b.main_binary IS NOT NULL
@@ -442,7 +444,7 @@ module Build = struct
     {| SELECT b.uuid, b.start_d, b.start_ps, b.finish_d, b.finish_ps,
             b.result_code, b.result_msg, b.console, b.script,
             b.platform, b.main_binary, b.input_id, b.user, b.job,
-            a.filepath, a.localpath, a.sha256, a.size
+            a.filepath, a.sha256, a.size
        FROM build_artifact a
        INNER JOIN build b ON b.id = a.build
        WHERE a.sha256 = ?
@@ -593,6 +595,8 @@ let migrate = [
   "CREATE INDEX idx_build_main_binary ON build(main_binary)";
   Caqti_type.unit ->. Caqti_type.unit @@
   "CREATE INDEX idx_build_artifact_sha256 ON build_artifact(sha256)";
+  Caqti_type.unit ->. Caqti_type.unit @@
+  "CREATE INDEX idx_build_artifact_build ON build_artifact(build)";
   set_current_version;
   set_application_id;
 ]
@@ -606,6 +610,8 @@ let rollback = [
   Build.rollback;
   Job.rollback;
   Caqti_type.unit ->. Caqti_type.unit @@
+  "DROP INDEX IF EXISTS idx_build_artifact_build";
+  Caqti_type.unit ->. Caqti_type.unit @@
   "DROP INDEX IF EXISTS idx_build_artifact_sha256";
   Caqti_type.unit ->. Caqti_type.unit @@
   "DROP INDEX IF EXISTS idx_build_failed";
diff --git a/db/builder_db.mli b/db/builder_db.mli
index 2988c12..9d1f052 100644
--- a/db/builder_db.mli
+++ b/db/builder_db.mli
@@ -3,7 +3,6 @@ module Rep : sig
   type 'a id
   type file = {
     filepath : Fpath.t;
-    localpath : Fpath.t;
     sha256 : Cstruct.t;
     size : int;
   }
@@ -23,7 +22,6 @@ type 'a id = 'a Rep.id
 
 type file = Rep.file = {
   filepath : Fpath.t;
-  localpath : Fpath.t;
   sha256 : Cstruct.t;
   size : int;
 }
@@ -87,6 +85,7 @@ module Build_artifact : sig
       Caqti_request.t
   val get_all_by_build :
     ([`build] id, [`build_artifact] id * file, [ `Many | `One | `Zero ]) Caqti_request.t
+  val exists : (Cstruct.t, bool, [ `One ]) Caqti_request.t
   val add :
     (file * [`build] id, unit, [ `Zero ]) Caqti_request.t
   val remove_by_build :
diff --git a/db/representation.ml b/db/representation.ml
index 4d94b93..1cc1722 100644
--- a/db/representation.ml
+++ b/db/representation.ml
@@ -30,7 +30,6 @@ let id_to_int64 (id : 'a id) : int64 = id
 
 type file = {
   filepath : Fpath.t;
-  localpath : Fpath.t;
   sha256 : Cstruct.t;
   size : int;
 }
@@ -63,24 +62,24 @@ let cstruct =
   Caqti_type.custom ~encode ~decode Caqti_type.octets
 
 let file =
-  let encode { filepath; localpath; sha256; size } =
-    Ok (filepath, localpath, sha256, size) in
-  let decode (filepath, localpath, sha256, size) =
-    Ok { filepath; localpath; sha256; size } in
-  Caqti_type.custom ~encode ~decode Caqti_type.(tup4 fpath fpath cstruct int)
+  let encode { filepath; sha256; size } =
+    Ok (filepath, sha256, size) in
+  let decode (filepath, sha256, size) =
+    Ok { filepath; sha256; size } in
+  Caqti_type.custom ~encode ~decode Caqti_type.(tup3 fpath cstruct int)
 
 let file_opt =
-  let rep = Caqti_type.(tup4 (option fpath) (option fpath) (option cstruct) (option int)) in
+  let rep = Caqti_type.(tup3 (option fpath) (option cstruct) (option int)) in
   let encode = function
-    | Some { filepath; localpath; sha256; size } ->
-      Ok (Some filepath, Some localpath, Some sha256, Some size)
+    | Some { filepath; sha256; size } ->
+      Ok (Some filepath, Some sha256, Some size)
     | None ->
-      Ok (None, None, None, None)
+      Ok (None, None, None)
   in
   let decode = function
-    | (Some filepath, Some localpath, Some sha256, Some size) ->
-      Ok (Some { filepath; localpath; sha256; size })
-    | (None, None, None, None) ->
+    | (Some filepath, Some sha256, Some size) ->
+      Ok (Some { filepath; sha256; size })
+    | (None, None, None) ->
       Ok None
     | _ ->
       (* This should not happen if the database is well-formed *)
diff --git a/lib/builder_web.ml b/lib/builder_web.ml
index 4a40dcf..feb596e 100644
--- a/lib/builder_web.ml
+++ b/lib/builder_web.ml
@@ -211,9 +211,9 @@ module Viz_aux = struct
     match typ with
     | `Treemap ->
       let debug_binary = 
-        let bin = Fpath.base main_binary.localpath in
+        let bin = Fpath.base main_binary.filepath in
         List.find_opt
-          (fun p -> Fpath.(equal (bin + "debug") (base p.localpath)))
+          (fun p -> Fpath.(equal (bin + "debug") (base p.filepath)))
           artifacts
       in
       begin
@@ -226,7 +226,7 @@ module Viz_aux = struct
     | `Dependencies -> 
       let opam_switch =
         List.find_opt
-          (fun p -> Fpath.(equal (v "opam-switch") (base p.localpath)))
+          (fun p -> Fpath.(equal (v "opam-switch") (base p.filepath)))
           artifacts
       in
       Model.not_found opam_switch
@@ -435,8 +435,8 @@ let routes ~datadir ~cachedir ~configdir ~expired_jobs =
     | _ ->
       Model.build_artifact_data datadir file
       |> if_error "Error getting build artifact"
-          ~log:(fun e -> Log.warn (fun m -> m "Error getting build artifact data for file %a in %a: %a"
-                           Fpath.pp file.Builder_db.filepath Fpath.pp file.Builder_db.localpath
+          ~log:(fun e -> Log.warn (fun m -> m "Error getting build artifact data for file %a: %a"
+                           Fpath.pp file.Builder_db.filepath
                            pp_error e)) >>= fun data ->
       let headers = [
         "Content-Type", mime_lookup file.Builder_db.filepath;
diff --git a/lib/dream_tar.ml b/lib/dream_tar.ml
index b5a5899..2cad5f6 100644
--- a/lib/dream_tar.ml
+++ b/lib/dream_tar.ml
@@ -67,7 +67,7 @@ let targz_response datadir finish (files : Builder_db.file list) (stream : Dream
   in
   Lwt_list.iter_s (fun file ->
       let hdr = header_of_file finish file in
-      write_block hdr Fpath.(datadir // file.localpath) state)
+      write_block hdr Fpath.(datadir // Model.artifact_path file) state)
     files >>= fun () ->
   Writer.really_write state Tar.Header.zero_block >>= fun () ->
   Writer.really_write state Tar.Header.zero_block >>= fun () ->
diff --git a/lib/model.ml b/lib/model.ml
index 91e25b4..59ad22e 100644
--- a/lib/model.ml
+++ b/lib/model.ml
@@ -19,6 +19,14 @@ let not_found = function
   | Some v -> Lwt_result.return v
 
 let staging datadir = Fpath.(datadir / "_staging")
+let artifact_path artifact =
+  let (`Hex sha256) = Hex.of_cstruct artifact.Builder_db.sha256 in
+  (* NOTE: [sha256] is 64 characters when it's a hex sha256 checksum *)
+  (* NOTE: We add the prefix to reduce the number of files in a directory - a
+     workaround for inferior filesystems. We can easily revert this by changing
+     this function and adding a migration. *)
+  let prefix = String.sub sha256 0 2 in
+  Fpath.(v "_artifacts" / prefix / sha256)
 
 let read_file datadir filepath =
   let filepath = Fpath.(datadir // filepath) in
@@ -44,14 +52,14 @@ let build_artifact_by_id id (module Db : CONN) =
   Db.find Builder_db.Build_artifact.get id
 
 let build_artifact_data datadir file =
-  read_file datadir file.Builder_db.localpath
+  read_file datadir (artifact_path file)
 
 let build_artifacts build (module Db : CONN) =
   Db.collect_list Builder_db.Build_artifact.get_all_by_build build >|=
   List.map snd
 
 let solo5_manifest datadir file =
-  let buf = Owee_buf.map_binary Fpath.(to_string (datadir // file.Builder_db.localpath)) in
+  let buf = Owee_buf.map_binary Fpath.(to_string (datadir // artifact_path file)) in
   Solo5_elftool.query_manifest buf |> Result.to_option
 
 let platforms_of_job id (module Db : CONN) =
@@ -196,11 +204,11 @@ let cleanup_staging datadir (module Db : Caqti_lwt.CONNECTION) =
        (cleanup_staged staged))
     stageds
 
-let save file data =
+let save path data =
   let open Lwt.Infix in
   Lwt.catch
     (fun () ->
-       Lwt_io.open_file ~mode:Lwt_io.Output (Fpath.to_string file) >>= fun oc ->
+       Lwt_io.open_file ~mode:Lwt_io.Output (Fpath.to_string path) >>= fun oc ->
        Lwt_io.write oc data >>= fun () ->
        Lwt_io.close oc
        |> Lwt_result.ok)
@@ -209,33 +217,29 @@ let save file data =
           Lwt_result.fail (`Msg (Unix.error_message e))
       | e -> Lwt.fail e)
 
-let save_file dir staging (filepath, data) =
-  let size = String.length data in
-  let sha256 = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data) in
-  let localpath = Fpath.append dir filepath in
-  let destpath = Fpath.append staging filepath in
-  Lwt_result.lift (Bos.OS.Dir.create (Fpath.parent destpath)) >>= fun _ ->
-  save destpath data >|= fun () ->
-  { Builder_db.filepath; localpath; sha256; size }
-
-let save_files dir staging files =
+let save_artifacts staging artifacts =
   List.fold_left
-    (fun r file ->
-       r >>= fun acc ->
-       save_file dir staging file >>= fun file ->
-       Lwt_result.return (file :: acc))
-    (Lwt_result.return [])
-    files
+    (fun r (file, data) ->
+       r >>= fun () ->
+       let (`Hex sha256) = Hex.of_cstruct file.Builder_db.sha256 in
+       let destpath = Fpath.(staging / sha256) in
+       save destpath data)
+    (Lwt_result.return ())
+    artifacts
 
-let save_all staging_dir (job : Builder.script_job) uuid artifacts =
-  let build_dir = Fpath.(v job.Builder.name / Uuidm.to_string uuid) in
-  let output_dir = Fpath.(build_dir / "output")
-  and staging_output_dir = Fpath.(staging_dir / "output") in
-  Lwt.return (Bos.OS.Dir.create staging_output_dir) >>= fun _ ->
-  save_files output_dir staging_output_dir artifacts >>= fun artifacts ->
-  Lwt_result.return artifacts
-
-let commit_files datadir staging_dir job_name uuid =
+let commit_files datadir staging_dir job_name uuid artifacts =
+  (* First we move the artifacts *)
+  List.fold_left
+    (fun r artifact ->
+       r >>= fun () ->
+       let (`Hex sha256) = Hex.of_cstruct artifact.Builder_db.sha256 in
+       let src = Fpath.(staging_dir / sha256) in
+       let dest = Fpath.(datadir // artifact_path artifact) in
+       Lwt.return (Bos.OS.Dir.create (Fpath.parent dest)) >>= fun _created ->
+       Lwt.return (Bos.OS.Path.move ~force:true src dest))
+    (Lwt_result.return ())
+    artifacts >>= fun () ->
+  (* Now the staging dir only contains script & console *)
   let job_dir = Fpath.(datadir / job_name) in
   let dest = Fpath.(job_dir / Uuidm.to_string uuid) in
   Lwt.return (Bos.OS.Dir.create job_dir) >>= fun _ ->
@@ -324,6 +328,25 @@ let prepare_staging staging_dir =
   then Lwt_result.fail (`Msg "build directory already exists")
   else Lwt_result.return ()
 
+(* saving:
+   - for each artifact compute its sha256 checksum -- calling Lwt.pause in
+     between
+   - lookup artifact sha256 in the database and filter them out of the list: not_in_db
+   - mkdir -p _staging/uuid/
+   - save console & script to _staging/uuid/
+   - save each artifact in not_in_db as _staging/uuid/sha256
+   committing:
+   - for each artifact mv _staging/uuid/sha256 _artifacts/sha256
+     (or _artifacts/prefix(sha256)/sha256 where prefix(sha256) is the first two hex digits in sha256)
+   - now _staging/uuid only contains console & script so we mv _staging/uuid _staging/job/uuid
+   potential issues:
+   - race condition in uploading same artifact:
+     * if the artifact already exists in the database and thus filesystem then nothing is done
+     * if the artifact is added to the database and/or filesystem we atomically overwrite it
+   - input_id depends on a sort order?
+   *)
+
+
 let add_build
     ~datadir
     ~cachedir
@@ -344,16 +367,35 @@ let add_build
         e)
       x
   in
-  let artifacts_to_preserve =
-    let not_interesting p =
-      String.equal (Fpath.basename p) "README.md" || String.equal (Fpath.get_ext p) ".build-hashes"
-    in
-    List.filter (fun (p, _) -> not (not_interesting p)) raw_artifacts
+  let not_interesting p =
+    String.equal (Fpath.basename p) "README.md" || String.equal (Fpath.get_ext p) ".build-hashes"
   in
+  begin
+    List.fold_left
+      (fun r (filepath, data) ->
+         r >>= fun acc ->
+         if not_interesting filepath then
+           Lwt_result.return acc
+         else
+           let sha256 = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data)
+           and size = String.length data in
+           Lwt_result.ok (Lwt.pause ()) >|= fun () ->
+           ({ filepath; sha256; size }, data) :: acc)
+      (Lwt_result.return [])
+      raw_artifacts
+  end >>= fun artifacts ->
   or_cleanup (prepare_staging staging_dir) >>= fun () ->
   or_cleanup (save_console_and_script staging_dir job_name uuid console job.Builder.script)
   >>= fun (console, script) ->
-  or_cleanup (save_all staging_dir job uuid artifacts_to_preserve) >>= fun artifacts ->
+  List.fold_left
+    (fun r ((f, _) as artifact) ->
+       r >>= fun acc ->
+       Db.find Builder_db.Build_artifact.exists f.sha256 >|= fun exists ->
+       if exists then acc else artifact :: acc)
+    (Lwt_result.return [])
+    artifacts >>= fun artifacts_to_save ->
+  or_cleanup (save_artifacts staging_dir artifacts_to_save) >>= fun () ->
+  let artifacts = List.map fst artifacts in
   let r =
     Db.start () >>= fun () ->
     Db.exec Job.try_add job_name >>= fun () ->
@@ -422,7 +464,7 @@ let add_build
       (Lwt_result.return ())
       remaining_artifacts_to_add >>= fun () ->
     Db.commit () >>= fun () ->
-    commit_files datadir staging_dir job_name uuid >|= fun () ->
+    commit_files datadir staging_dir job_name uuid artifacts >|= fun () ->
     main_binary
   in
   Lwt_result.bind_lwt_error (or_cleanup r)
@@ -451,7 +493,8 @@ let add_build
              "--uuid=" ^ uuid ; "--platform=" ^ platform ;
              "--cache-dir=" ^ Fpath.to_string cachedir ;
              "--data-dir=" ^ Fpath.to_string datadir ;
-             fp_str main_binary.localpath ])
+             "--main-binary-filepath=" ^ Fpath.to_string main_binary.filepath ;
+             fp_str Fpath.(datadir // artifact_path main_binary) ])
     in
     Log.debug (fun m -> m "executing hooks with %s" args);
     let dir = Fpath.(configdir / "upload-hooks") in
diff --git a/lib/model.mli b/lib/model.mli
index 2b36a7c..c062f92 100644
--- a/lib/model.mli
+++ b/lib/model.mli
@@ -5,6 +5,7 @@ val pp_error : Format.formatter -> error -> unit
 val not_found : 'a option -> ('a, [> `Not_found ]) result Lwt.t
 
 val staging : Fpath.t -> Fpath.t
+val artifact_path : Builder_db.file -> Fpath.t
 
 val cleanup_staging : Fpath.t -> Caqti_lwt.connection ->
   (unit, [> `Msg of string ]) result Lwt.t
diff --git a/lib/views.ml b/lib/views.ml
index 9e9e3e3..8a597f8 100644
--- a/lib/views.ml
+++ b/lib/views.ml
@@ -188,7 +188,7 @@ let artifact
     ~basename
     ~job_name
     ~build
-    ~file:{ Builder_db.filepath; localpath = _; sha256; size }
+    ~file:{ Builder_db.filepath; sha256; size }
   =
   let artifact_link =
     Link.Job_build_artifact.make
diff --git a/packaging/FreeBSD-repo.sh b/packaging/FreeBSD-repo.sh
index 9d76033..05e3a69 100755
--- a/packaging/FreeBSD-repo.sh
+++ b/packaging/FreeBSD-repo.sh
@@ -32,6 +32,8 @@ Options:
         Hex encoded SHA256 digest of the main binary.
     --job=STRING
         Job name that was built.
+    --main-binary-filepath=STRING
+        The file path of the main binary.
 EOM
     exit 1
 }
@@ -39,6 +41,7 @@ EOM
 BUILD_TIME=
 SHA=
 JOB=
+FILEPATH=
 
 while [ $# -gt 1 ]; do
     OPT="$1"
@@ -53,6 +56,9 @@ while [ $# -gt 1 ]; do
         --job=*)
             JOB="${OPT##*=}"
             ;;
+        --main-binary-filepath=*)
+            FILEPATH="${OPT##*=}"
+            ;;
         --*)
             warn "Ignoring unknown option: '${OPT}'"
             ;;
@@ -67,13 +73,14 @@ done
 [ -z "${BUILD_TIME}" ] && die "The --build-time option must be specified"
 [ -z "${SHA}" ] && die "The --sha256 option must be specified"
 [ -z "${JOB}" ] && die "The --job option must be specified"
+[ -z "${FILEPATH}" ] && die "The --main-binary-filepath option must be specified"
 
 FILENAME="${1}"
 
 : "${REPO:="/usr/local/www/pkg"}"
 : "${REPO_KEY:="/usr/local/etc/builder-web/repo.key"}"
 
-if [ "$(basename "${FILENAME}" .pkg)" = "$(basename "${FILENAME}")" ]; then
+if [ "$(basename "${FILEPATH}" .pkg)" = "$(basename "${FILEPATH}")" ]; then
     echo "Not a FreeBSD package"
     exit 0
 fi
diff --git a/packaging/dpkg-repo.sh b/packaging/dpkg-repo.sh
index 4cfd61d..6b47cf0 100755
--- a/packaging/dpkg-repo.sh
+++ b/packaging/dpkg-repo.sh
@@ -36,6 +36,8 @@ Options:
         Job name that was built.
     --platform=STRING
         Platform name on which the build was performed.
+    --main-binary-filepath=STRING
+        The file path of the main binary.
 EOM
     exit 1
 }
@@ -44,6 +46,7 @@ BUILD_TIME=
 SHA=
 JOB=
 PLATFORM=
+FILEPATH=
 
 while [ $# -gt 1 ]; do
     OPT="$1"
@@ -61,6 +64,9 @@ while [ $# -gt 1 ]; do
         --platform=*)
             PLATFORM="${OPT##*=}"
             ;;
+        --main-binary-filepath=*)
+            FILEPATH="${OPT##*=}"
+            ;;
         --*)
             warn "Ignoring unknown option: '${OPT}'"
             ;;
@@ -76,10 +82,11 @@ done
 [ -z "${SHA}" ] && die "The --sha256 option must be specified"
 [ -z "${JOB}" ] && die "The --job option must be specified"
 [ -z "${PLATFORM}" ] && die "The --platform option must be specified"
+[ -z "${FILEPATH}" ] && die "The --main-binary-filepath option must be specified"
 
 FILENAME="${1}"
 
-if [ $(basename "${FILENAME}" .deb) = $(basename "${FILENAME}") ]; then
+if [ $(basename "${FILEPATH}" .deb) = $(basename "${FILEPATH}") ]; then
   echo "Not a Debian package"
   exit 0
 fi
diff --git a/packaging/visualizations.sh b/packaging/visualizations.sh
index a2f5c8d..5e575df 100755
--- a/packaging/visualizations.sh
+++ b/packaging/visualizations.sh
@@ -75,7 +75,8 @@ info "processing UUID '${UUID}'"
 DB="${DATA_DIR}/builder.sqlite3"
 
 get_main_binary () {
-    sqlite3 "${DB}" "SELECT ba.localpath FROM build AS b
+    sqlite3 "${DB}" "SELECT '_artifacts/' || substr(lower(hex(ba.sha256)), 1, 2) || '/' || lower(hex(ba.sha256))
+        FROM build AS b
         JOIN build_artifact AS ba ON ba.build = b.id AND b.main_binary = ba.id
         WHERE uuid = '${UUID}';"
 }
@@ -84,17 +85,19 @@ BIN="${DATA_DIR}/$(get_main_binary)" || die "Failed to get main binary from data
 [ -z "${BIN}" ] && die "No main-binary found in db '${DB}' for build '${UUID}'"
 
 get_debug_binary () {
-    sqlite3 "${DB}" "SELECT ba.localpath FROM build AS b
+    sqlite3 "${DB}" "SELECT '_artifacts/' || substr(lower(hex(ba.sha256)), 1, 2) || '/' || lower(hex(ba.sha256))
+        FROM build AS b
         JOIN build_artifact AS ba ON ba.build = b.id
         WHERE
           uuid = '${UUID}'
-          AND ba.localpath LIKE '%.debug';"
+          AND ba.filepath LIKE '%.debug';"
 }
 
 DEBUG_BIN_RELATIVE="$(get_debug_binary)" || die "Failed to get debug binary from database"
 
 get_opam_switch () {
-    sqlite3 "${DB}" "SELECT ba.localpath FROM build AS b
+    sqlite3 "${DB}" "SELECT '_artifacts/' || substr(lower(hex(ba.sha256)), 1, 2) || '/' || lower(hex(ba.sha256))
+        FROM build AS b
         JOIN build_artifact AS ba ON ba.build = b.id
         WHERE
           uuid = '${UUID}'
diff --git a/test/test_builder_db.ml b/test/test_builder_db.ml
index ce2d257..db56022 100644
--- a/test/test_builder_db.ml
+++ b/test/test_builder_db.ml
@@ -43,18 +43,15 @@ module Testable = struct
   let file =
     let equal (x : Builder_db.Rep.file) (y : Builder_db.Rep.file) =
       Fpath.equal x.filepath y.filepath &&
-      Fpath.equal x.localpath y.localpath &&
       Cstruct.equal x.sha256 y.sha256 &&
       x.size = y.size
     in
-    let pp ppf { Builder_db.Rep.filepath; localpath; sha256; size } =
+    let pp ppf { Builder_db.Rep.filepath; sha256; size } =
       Format.fprintf ppf "{@[<v 1>@;<1 0>Builder_db.Rep.filepath = %a;@;<1 0>\
-                          localpath = %a;@;<1 0>\
                           sha256 = %a;@;<1 0>\
                           size = %d;@;<1 0>\
                           @]@,}"
-        Fpath.pp filepath Fpath.pp localpath
-        Cstruct.hexdump_pp sha256 size
+        Fpath.pp filepath Cstruct.hexdump_pp sha256 size
     in
     Alcotest.testable pp equal
 
@@ -133,11 +130,10 @@ let finish = Option.get (Ptime.of_float_s 1.)
 let result = Builder.Exited 0
 let main_binary =
   let filepath = Result.get_ok (Fpath.of_string "bin/hello.sh") in
-  let localpath = Result.get_ok (Fpath.of_string "/dev/null") in
   let data = "#!/bin/sh\necho Hello, World\n" in
   let sha256 = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data) in
   let size = String.length data in
-  { Builder_db.Rep.filepath; localpath; sha256; size }
+  { Builder_db.Rep.filepath; sha256; size }
 let main_binary2 =
   let data = "#!/bin/sh\necho Hello, World 2\n" in
   let sha256 = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data) in
@@ -149,21 +145,17 @@ let fail_if_none a =
   Option.to_result ~none:(`Msg "Failed to retrieve") a
 
 let add_test_build user_id (module Db : CONN) =
-  let r =
-    let open Builder_db in
-    Db.start () >>= fun () ->
-    Db.exec Job.try_add job_name >>= fun () ->
-    Db.find_opt Job.get_id_by_name job_name >>= fail_if_none >>= fun job_id ->
-    Db.exec Build.add { Build.uuid; start; finish; result; console; script; platform;
-                        main_binary = None; input_id = None; user_id; job_id } >>= fun () ->
-    Db.find last_insert_rowid () >>= fun id ->
-    Db.exec Build_artifact.add (main_binary, id) >>= fun () ->
-    Db.find last_insert_rowid () >>= fun main_binary_id ->
-    Db.exec Build.set_main_binary (id, main_binary_id) >>= fun () ->
-    Db.commit ()
-  in
-  Result.fold ~ok:Result.ok ~error:(fun _ -> Db.rollback ())
-    r
+  let open Builder_db in
+  Db.start () >>= fun () ->
+  Db.exec Job.try_add job_name >>= fun () ->
+  Db.find_opt Job.get_id_by_name job_name >>= fail_if_none >>= fun job_id ->
+  Db.exec Build.add { Build.uuid; start; finish; result; console; script; platform;
+                      main_binary = None; input_id = None; user_id; job_id } >>= fun () ->
+  Db.find last_insert_rowid () >>= fun id ->
+  Db.exec Build_artifact.add (main_binary, id) >>= fun () ->
+  Db.find last_insert_rowid () >>= fun main_binary_id ->
+  Db.exec Build.set_main_binary (id, main_binary_id) >>= fun () ->
+  Db.commit ()
 
 let with_build_db f () =
   or_fail
@@ -269,6 +261,14 @@ let test_artifact_get_by_build_uuid (module Db : CONN) =
   get_opt "no build" >>| fun (_id, file) ->
   Alcotest.(check Testable.file) "same file" file main_binary
 
+let test_artifact_exists_true (module Db : CONN) =
+  Db.find Builder_db.Build_artifact.exists main_binary.sha256 >>| fun exists ->
+  Alcotest.(check bool) "main binary exists" true exists
+
+let test_artifact_exists_false (module Db : CONN) =
+  Db.find Builder_db.Build_artifact.exists main_binary2.sha256 >>| fun exists ->
+  Alcotest.(check bool) "main binary2 doesn't exists" false exists
+
 (* XXX: This test should fail because main_binary on the corresponding build
  * references its main_binary. This is not the case now due to foreign key. *)
 let test_artifact_remove_by_build (module Db : CONN) =
@@ -306,6 +306,8 @@ let () =
     "build-artifact", [
       test_case "Get all by build" `Quick (with_build_db test_artifact_get_all_by_build);
       test_case "Get by build uuid" `Quick (with_build_db test_artifact_get_by_build_uuid);
+      test_case "Artifact exists" `Quick (with_build_db test_artifact_exists_true);
+      test_case "Other artifact doesn't exists" `Quick (with_build_db test_artifact_exists_false);
       test_case "Remove by build" `Quick (with_build_db test_artifact_remove_by_build);
     ];
   ]