Changeset 26292 for trunk/Nebulous

Timestamp:

Nov 30, 2009, 1:54:49 PM (17 years ago)

Author:

watersc1

Message:

Nebulous: Implemented a number of bug fixes and modifications to

ensure no loss of data.

• Each volume can now be associated into a cabinet, defining their physical arrangement.
• File creation: new files without a specified volume are created on a random volume from a subset of the N least full.
• Replication: file replication uses the same volume selection method, with the constraints that a copy not be automatically placed on the same volume as another, and that the first copy not be housed within the same volume.
• Cull: instead of removing the first available instance, first attempt to remove an instance on the same volume as another, then attempt to remove an instance in the same cabinet as another, and then remove the first only if those fail.
• Corrected bug that prevented the deletion of an object if it had more than one unavailable instance.
• Fixed nebdiskd to synchronize between volume->mountedvol tables and to properly remove volumes that were no longer accessible.

File:

• trunk/Nebulous/lib/Nebulous/Client.pm (modified) (3 diffs)

trunk/Nebulous/lib/Nebulous/Client.pm

@@ -315 +315 @@
     my $locations;
     if (defined $vol_name) {
-        $locations = $self->find_instances($key, $vol_name);
+        $locations = $self->find_instances_for_cull($key, $vol_name);
     } else {
-        $locations = $self->find_instances($key);
+        $locations = $self->find_instances_for_cull($key);
     }
 
@@ -326 +326 @@
         return;
     }
-
-    my $uri = $self->delete_instance($key, @$locations[0]);
+    
+    # Calculate which is the best instance to remove. First, see if we have two copies
+    # on one volume, if so, delete the first of those copies. 
+    my $delete_index = -1;
+
+    for (my $i = 0 ; $i <= $#{ $locations }; $i++) {
+        for (my $j = $i + 1; $j <= $#{ $locations }; $j++) {
+            if (@$locations[$i]->{vol_id} eq @$locations[$j]->{vol_id}) {
+                $delete_index = $i;
+            }
+        }
+    }
+    # If we don't have two copies on one volume, see if we have two copies on a single 
+    # cabinet. If so, delete the first of those copies.
+    if ($delete_index == -1) {
+        for (my $i = 0 ; $i <= $#{ $locations }; $i++) {
+            for (my $j = $i + 1; $j <= $#{ $locations }; $j++) {
+                if (@$locations[$i]->{cab_id} eq @$locations[$j]->{cab_id}) {
+                    $delete_index = $i;
+                }
+            }
+        }
+    }
+    # Fail-safe. We didn't have any duplicates (the instances are "well-mixed"), so 
+    # delete the first.
+    if ($delete_index == -1) {
+        $delete_index = 0;
+    }    
+    my $uri = $self->delete_instance($key, @$locations[$delete_index]->{uri});
 
     eval {
-        _nuke_file(_get_file_path(@$locations[0]));
+        _nuke_file(_get_file_path(@$locations[$delete_index]->{uri}));
     };
     if ($@) {
@@ -758 +785 @@
 }
 
+sub find_instances_for_cull
+{
+    my $self = shift;
+
+    my ( $key, @params ) = validate_pos( @_,
+        {
+            type        => SCALAR,
+        },
+        {
+            #volume
+            type        => SCALAR|UNDEF,
+            optional    => 1,
+        },
+    );
+
+    $log->debug( "entered - @_" );
+
+    my $response = $self->{ 'server' }->find_instances_for_cull( $key, @params );
+    if ( $response->fault ) {
+        $self->set_err($response->faultstring);
+        # check to see if this failure is because $key doesn't exist
+        if ($response->faultstring =~ /is valid object key/) {
+            $log->debug( "leaving" );
+            return;
+        }
+        # key is valid but no instances are on the specified volume
+        if ($response->faultstring =~ /no instances on storage volume/) {
+            $log->debug( "leaving" );
+            return;
+        }
+
+        $log->logdie("unhandled fault - ", $self->err);
+    }
+
+    my $uris = $response->result;
+
+    $log->debug( "server found: @$uris" );
+
+    $log->debug( "leaving" );
+
+    return $uris;
+}
+
 
 sub find