LocalBlobAccess: Double the recommended number of attempts

Right now we set the maximum get attempts to just eight. This might be a
bit too tight, requiring users to create KeyLocationMaps that are
unnecessarily big. Given that nobody has really complained about these
values being too large, let's bump them.

README.md

@@ -51,8 +51,8 @@ $ cat config/bb_storage.jsonnet
             sizeBytes: 16 * 1024 * 1024,
           },
         },
-        keyLocationMapMaximumGetAttempts: 8,
-        keyLocationMapMaximumPutAttempts: 32,
+        keyLocationMapMaximumGetAttempts: 16,
+        keyLocationMapMaximumPutAttempts: 64,
         oldBlocks: 8,
         currentBlocks: 24,
         newBlocks: 3,
@@ -86,8 +86,8 @@ $ cat config/bb_storage.jsonnet
                 sizeBytes: 1024 * 1024,
               },
             },
-            keyLocationMapMaximumGetAttempts: 8,
-            keyLocationMapMaximumPutAttempts: 32,
+            keyLocationMapMaximumGetAttempts: 16,
+            keyLocationMapMaximumPutAttempts: 64,
             oldBlocks: 8,
             currentBlocks: 24,
             newBlocks: 1,

doc/zh_CN/README.md

@@ -31,8 +31,8 @@ $ cat config/bb_storage.jsonnet
             sizeBytes: 16 * 1024 * 1024,
           },
         },
-        keyLocationMapMaximumGetAttempts: 8,
-        keyLocationMapMaximumPutAttempts: 32,
+        keyLocationMapMaximumGetAttempts: 16,
+        keyLocationMapMaximumPutAttempts: 64,
         oldBlocks: 8,
         currentBlocks: 24,
         newBlocks: 3,
@@ -60,8 +60,8 @@ $ cat config/bb_storage.jsonnet
               sizeBytes: 1024 * 1024,
             },
           },
-          keyLocationMapMaximumGetAttempts: 8,
-          keyLocationMapMaximumPutAttempts: 32,
+          keyLocationMapMaximumGetAttempts: 16,
+          keyLocationMapMaximumPutAttempts: 64,
           oldBlocks: 8,
           currentBlocks: 24,
           newBlocks: 1,

pkg/proto/configuration/blobstore/blobstore.proto

@@ -425,7 +425,7 @@ message LocalBlobAccessConfiguration {
   // there is only a 0.1^16 chance that inserting an entry prematurely
   // displaces another object from storage.
   //
-  // Recommended value: 8
+  // Recommended value: 16
   uint32 key_location_map_maximum_get_attempts = 2;
 
   // The number of mutations that a Put() on the key-location map may
@@ -435,7 +435,7 @@ message LocalBlobAccessConfiguration {
   // displaced. Because of that, it is recommended to set this field to
   // a small multiple of the maximum Get() attempts.
   //
-  // Recommended value: 32
+  // Recommended value: 64
   int64 key_location_map_maximum_put_attempts = 3;
 
   // The number of blocks, where attempting to access any data stored