update dsync implementation to fix a regression (#5513)

Currently minio master requires 4 servers, we
have decided to run on a minimum of 2 servers
instead - fixes a regression from previous
releases where 3 server setups were supported.

cmd/endpoint_test.go

@@ -108,7 +108,7 @@ func TestNewEndpointList(t *testing.T) {
 		{[]string{"d1", "d2", "d3", "d1"}, fmt.Errorf("duplicate endpoints found")},
 		{[]string{"d1", "d2", "d3", "./d1"}, fmt.Errorf("duplicate endpoints found")},
 		{[]string{"http://localhost/d1", "http://localhost/d2", "http://localhost/d1", "http://localhost/d4"}, fmt.Errorf("duplicate endpoints found")},
-		{[]string{"d1", "d2", "d3", "d4", "d5"}, fmt.Errorf("A total of 5 endpoints were found. For erasure mode it should be an even number between 4 and 16")},
+		{[]string{"d1", "d2", "d3", "d4", "d5"}, fmt.Errorf("A total of 5 endpoints were found. For erasure mode it should be an even number between 4 and 32")},
 		{[]string{"ftp://server/d1", "http://server/d2", "http://server/d3", "http://server/d4"}, fmt.Errorf("'ftp://server/d1': invalid URL endpoint format")},
 		{[]string{"d1", "http://localhost/d2", "d3", "d4"}, fmt.Errorf("mixed style endpoints are not supported")},
 		{[]string{"http://example.org/d1", "https://example.com/d1", "http://example.net/d1", "https://example.edut/d1"}, fmt.Errorf("mixed scheme is not supported")},

cmd/xl-v1.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ * Minio Cloud Storage, (C) 2016, 2017, 2018 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,7 +35,7 @@ const (
 	uploadsJSONFile = "uploads.json"
 
 	// Maximum erasure blocks.
-	maxErasureBlocks = 16
+	maxErasureBlocks = 32
 
 	// Minimum erasure blocks.
 	minErasureBlocks = 4
@@ -51,6 +51,7 @@ type xlObjects struct {
 
 	// name space mutex for object layer
 	nsMutex *nsLockMap
+
 	// Variable represents bucket policies in memory.
 	bucketPolicies *bucketPolicies
 }