Merge branch 'new_gc' into discoproject

Author: pmundkur

Makefile

@@ -120,7 +120,7 @@ test: master $(ETESTOBJECTS)
 
 dialyzer: EOPT = -W +debug_info
 dialyzer: $(EPLT)
-	$(DIALYZER) --get_warnings -Wunmatched_returns -Werror_handling -Wbehaviours --plt $(EPLT) --src -r $(ESRC)
+	$(DIALYZER) --get_warnings -Wunmatched_returns -Werror_handling --plt $(EPLT) --src -r $(ESRC)
 
 typer: $(EPLT)
 	$(TYPER) --plt $(EPLT) -r $(ESRC)

lib/disco/settings.py

@@ -222,6 +222,11 @@
                 The default write authorization token to use.
                 Default is ``None``.
 
+        .. envvar:: DDFS_GC_INITIAL_WAIT
+
+                The amount of time to wait after startup before running GC (in minutes).
+                Default is ``''``, which triggers an internal default of 5 minutes.
+
         .. envvar:: DDFS_PARANOID_DELETE
 
                 Instead of deleting unneeded files, DDFS garbage collector prefixes obsolete files with ``!trash.``, so they can be safely verified/deleted by an external process. For instance, the following command can be used to finally delete the files (assuming that ``DDFS_DATA = "/srv/disco/ddfs"``)::
@@ -307,7 +312,8 @@ class DiscoSettings(Settings):
         'DDFS_TAG_MIN_REPLICAS': "1",
         'DDFS_TAG_REPLICAS':     "1",
         'DDFS_BLOB_REPLICAS':    "1",
-        'DDFS_PARANOID_DELETE':  "''"
+        'DDFS_PARANOID_DELETE':  "''",
+        'DDFS_GC_INITIAL_WAIT':  "''"
         }
 
     globals = globals()

master/src/ddfs/config.hrl

@@ -11,12 +11,12 @@
 % How many replicas by default
 % -define(DEFAULT_REPLICAS, 3).
 
-% How long to wait for replies from nodes
--define(NODE_TIMEOUT, 5 * ?SECOND).
-
 % How long ddfs node startup can take
 -define(NODE_STARTUP, 1 * ?MINUTE).
 
+% How long to wait for replies from nodes
+-define(NODE_TIMEOUT, 10 * ?SECOND).
+
 % How long to wait for a reply from and operation that accesses nodes
 % (>NODE_TIMEOUT)
 -define(NODEOP_TIMEOUT, 1 * ?MINUTE).
@@ -60,12 +60,33 @@
 % Time to wait between garbage collection runs
 -define(GC_INTERVAL, ?DAY).
 
+% Max duration for a GC run.  This should be smaller than
+% min(ORPHANED_{BLOB,TAG}_EXPIRES).
+-define(GC_MAX_DURATION, 3 * ?DAY).
+
+% Time to wait after startup for cluster to stabilize before running
+% first GC.
+-define(GC_DEFAULT_INITIAL_WAIT, 5 * ?MINUTE).
+
+% Maximum number of times we try to bring up a node that failed during
+% GC before we abort GC.
+-define(MAX_GC_NODE_FAILURES, 3).
+
+% The longest potential interval between messages in the GC protocol;
+% used to ensure GC makes forward progress.  This can be set to the
+% estimated time to traverse all the volumes on a DDFS node.
+-define(GC_PROGRESS_INTERVAL, 30 * ?MINUTE).
+
 % Tag cache expires in this many milliseconds if tag can't be fetched
 -define(TAG_EXPIRES_ONERROR, 1 * ?SECOND).
 
 % Number of tag replicas: min(length(Nodes), ?TAG_REPLICAS)
 % -define(TAG_REPLICAS, 3).
 
+% Number of extra replicas (i.e. lost replicas recovered during GC) to
+% allow before deleting extra replicas.
+-define(NUM_EXTRA_REPLICAS, 1).
+
 % Permissions for blobs and tags
 -define(FILE_MODE, 8#00400).
 
@@ -94,19 +115,25 @@
 % Delete !partial leftovers after this many milliseconds
 -define(PARTIAL_EXPIRES, ?DAY).
 
-% When orphaned blob can be deleted 
+% When orphaned blob can be deleted
 -define(ORPHANED_BLOB_EXPIRES, 5 * ?DAY).
 
-% When orphaned tag can be deleted 
+% When orphaned tag can be deleted
 -define(ORPHANED_TAG_EXPIRES, 5 * ?DAY).
 
 % How long a tag has to stay on the deleted list before
 % we can permanently forget it, after all known instances
-% of the tag object have been removed. This quarantine period 
-% ensures that a node that was temporarily unavailable 
+% of the tag object have been removed. This quarantine period
+% ensures that a node that was temporarily unavailable
 % and reactivates can't resurrect deleted tags. You
 % must ensure that all temporarily inactive nodes
 % are reactivated (or cleaned) within the ?DELETED_TAG_EXPIRES
 % time frame. To be on the safe side, make the period long
 % enough.
 -define(DELETED_TAG_EXPIRES, 30 * ?DAY).
+
+% How many times a tag operation should be retried before aborting.
+-define(MAX_TAG_OP_RETRIES, 3).
+
+% How long to wait before timing out a tag retrieval.
+-define(GET_TAG_TIMEOUT, 5 * ?MINUTE).

master/src/ddfs/ddfs.hrl

@@ -0,0 +1,12 @@
+-type host() :: nonempty_string().
+-type path() :: nonempty_string().
+-type volume_name() :: nonempty_string().
+
+% Diskinfo is {FreeSpace, UsedSpace}.
+-type diskinfo() :: {non_neg_integer(), non_neg_integer()}.
+-type volume() :: {diskinfo(), volume_name()}.
+
+-type object_type() :: 'blob' | 'tag'.
+-type object_name() :: binary().
+-type url() :: binary().
+-type taginfo() :: {erlang:timestamp(), volume_name()}.