Fix delays and iterim fix for the partial fix in #3502 (#3511)

This patch uses a technique where in a retryable storage
before object layer initialization has a higher delay
and waits for longer period upto 4 times with time unit
of seconds.

And uses another set of configuration after the disks
have been formatted, i.e use a lower retry backoff rate
and retrying only once per 5 millisecond.

Network IO error count is reduced to a lower value i.e 256
before we reject the disk completely. This is done so that
combination of retry logic and total error count roughly
come to around 2.5secs which is when we basically take the
disk offline completely.

NOTE: This patch doesn't fix the issue of what if the disk
is completely dead and comes back again after the initialization.
Such a mutating state requires a change in our startup sequence
which will be done subsequently. This is an interim fix to alleviate
users from these issues.

cmd/auth-rpc-client.go

@@ -22,6 +22,10 @@ import (
 	"time"
 )
 
+// Attempt to retry only this many number of times before
+// giving up on the remote RPC entirely.
+const globalAuthRPCRetryThreshold = 1
+
 // GenericReply represents any generic RPC reply.
 type GenericReply struct{}
 
@@ -165,7 +169,7 @@ func (authClient *AuthRPCClient) Call(serviceMethod string, args interface {
 			authClient.Close()
 
 			// No need to return error until the retry count threshold has reached.
-			if i < globalMaxAuthRPCRetryThreshold {
+			if i < globalAuthRPCRetryThreshold {
 				continue
 			}
 		}

cmd/fs-v1_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"path/filepath"
 	"testing"
+	"time"
 )
 
 // TestNewFS - tests initialization of all input disks
@@ -86,7 +87,12 @@ func TestNewFS(t *testing.T) {
 	if err != errInvalidArgument {
 		t.Errorf("Expecting error invalid argument, got %s", err)
 	}
-	_, err = newFSObjects(&retryStorage{xlStorageDisks[0]})
+	_, err = newFSObjects(&retryStorage{
+		remoteStorage:    xlStorageDisks[0],
+		maxRetryAttempts: 1,
+		retryUnit:        time.Millisecond,
+		retryCap:         time.Millisecond * 10,
+	})
 	if err != nil {
 		errMsg := "Unable to recognize backend format, Disk is not in FS format."
 		if err.Error() == errMsg {

cmd/globals.go

@@ -89,14 +89,6 @@ var (
 	// List of admin peers.
 	globalAdminPeers = adminPeers{}
 
-	// Attempt to retry only this many number of times before
-	// giving up on the remote disk entirely.
-	globalMaxStorageRetryThreshold = 3
-
-	// Attempt to retry only this many number of times before
-	// giving up on the remote RPC entirely.
-	globalMaxAuthRPCRetryThreshold = 1
-
 	// Add new variable global values here.
 )
 

cmd/prepare-storage.go

@@ -311,16 +311,40 @@ func waitForFormatDisks(firstDisk bool, endpoints []*url.URL, storageDisks []Sto
 	if storageDisks == nil {
 		return nil, errInvalidArgument
 	}
+
+	// Retryable disks before formatting, we need to have a larger
+	// retry window so that we wait enough amount of time before
+	// the disks come online.
+	retryDisks := make([]StorageAPI, len(storageDisks))
+	for i, storage := range storageDisks {
+		retryDisks[i] = &retryStorage{
+			remoteStorage:    storage,
+			maxRetryAttempts: globalStorageInitRetryThreshold,
+			retryUnit:        time.Second,
+			retryCap:         time.Second * 30, // 30 seconds.
+		}
+	}
+
 	// Start retry loop retrying until disks are formatted properly, until we have reached
 	// a conditional quorum of formatted disks.
-	err = retryFormattingDisks(firstDisk, endpoints, storageDisks)
+	err = retryFormattingDisks(firstDisk, endpoints, retryDisks)
 	if err != nil {
 		return nil, err
 	}
+
 	// Initialize the disk into a formatted disks wrapper.
 	formattedDisks = make([]StorageAPI, len(storageDisks))
 	for i, storage := range storageDisks {
-		formattedDisks[i] = &retryStorage{storage}
+		// After formatting is done we need a smaller time
+		// window and lower retry value before formatting.
+		formattedDisks[i] = &retryStorage{
+			remoteStorage:    storage,
+			maxRetryAttempts: globalStorageRetryThreshold,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 5, // 5 milliseconds.
+		}
 	}
+
+	// Success.
 	return formattedDisks, nil
 }

cmd/retry-storage.go

@@ -22,12 +22,25 @@ import (
 	"github.com/minio/minio/pkg/disk"
 )
 
+const (
+	// Attempt to retry only this many number of times before
+	// giving up on the remote disk entirely during initialization.
+	globalStorageInitRetryThreshold = 4
+
+	// Attempt to retry only this many number of times before
+	// giving up on the remote disk entirely after initialization.
+	globalStorageRetryThreshold = 1
+)
+
 // Retry storage is an instance of StorageAPI which
 // additionally verifies upon network shutdown if the
 // underlying storage is available and is really
 // formatted.
 type retryStorage struct {
-	remoteStorage StorageAPI
+	remoteStorage    StorageAPI
+	maxRetryAttempts int
+	retryUnit        time.Duration
+	retryCap         time.Duration
 }
 
 // String representation of remoteStorage.
@@ -209,13 +222,13 @@ func (f retryStorage) reInit() (err error) {
 
 	doneCh := make(chan struct{})
 	defer close(doneCh)
-	for i := range newRetryTimer(time.Second, time.Second*30, MaxJitter, doneCh) {
+	for i := range newRetryTimer(f.retryUnit, f.retryCap, MaxJitter, doneCh) {
 		// Initialize and make a new login attempt.
 		err = f.remoteStorage.Init()
 		if err != nil {
 			// No need to return error until the retry count
 			// threshold has reached.
-			if i < globalMaxStorageRetryThreshold {
+			if i < f.maxRetryAttempts {
 				continue
 			}
 			return err
@@ -226,7 +239,7 @@ func (f retryStorage) reInit() (err error) {
 		if err != nil {
 			// No need to return error until the retry count
 			// threshold has reached.
-			if i < globalMaxStorageRetryThreshold {
+			if i < f.maxRetryAttempts {
 				continue
 			}
 			return err

cmd/retry-storage_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"reflect"
 	"testing"
+	"time"
 )
 
 // Tests retry storage.
@@ -39,9 +40,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	// Validate all the conditions for retrying calls.
@@ -52,9 +58,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -77,9 +88,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -97,9 +113,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -114,9 +135,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -131,9 +157,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -151,9 +182,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -168,9 +204,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -185,9 +226,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -202,9 +248,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -223,9 +274,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -248,9 +304,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -268,9 +329,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -285,9 +351,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {
@@ -306,9 +377,14 @@ func TestRetryStorage(t *testing.T) {
 		if !ok {
 			t.Fatal("storage disk is not *retryStorage type")
 		}
-		storageDisks[i] = &retryStorage{newNaughtyDisk(retryDisk, map[int]error{
+		storageDisks[i] = &retryStorage{
-			1: errDiskNotFound,
+			remoteStorage: newNaughtyDisk(retryDisk, map[int]error{
-		}, nil)}
+				1: errDiskNotFound,
+			}, nil),
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}
 	}
 
 	for _, disk := range storageDisks {

cmd/retry.go

@@ -90,7 +90,7 @@ func newRetryTimer(unit time.Duration, cap time.Duration, jitter float64, doneCh
 
 	go func() {
 		defer close(attemptCh)
-		nextBackoff := 1
+		nextBackoff := 0
 		for {
 			select {
 			// Attempts starts.

cmd/storage-rpc-client.go

@@ -241,8 +241,14 @@ func (n *networkStorage) String() string {
 	return n.netAddr + ":" + n.netPath
 }
 
-// maximum allowed network IOError.
+// Network IO error count is kept at 256 with some simple
-const maxAllowedNetworkIOError = 1024
+// math. Before we reject the disk completely. The combination
+// of retry logic and total error count roughly comes around
+// 2.5secs ( 2 * 5 * time.Millisecond * 256) which is when we
+// basically take the disk offline completely. This is considered
+// sufficient time tradeoff to avoid large delays in-terms of
+// incoming i/o.
+const maxAllowedNetworkIOError = 256 // maximum allowed network IOError.
 
 // Initializes the remote RPC connection by attempting a login attempt.
 func (n *networkStorage) Init() (err error) {

cmd/test-utils_test.go

@@ -65,9 +65,6 @@ func init() {
 
 	// Enable caching.
 	setMaxMemory()
-
-	// Tests don't need to retry.
-	globalMaxStorageRetryThreshold = 1
 }
 
 func prepareFS() (ObjectLayer, string, error) {
@@ -1656,7 +1653,12 @@ func prepareNErroredDisks(storageDisks []StorageAPI, offline int, err error, t *
 	}
 
 	for i := 0; i < offline; i++ {
-		storageDisks[i] = &naughtyDisk{disk: &retryStorage{storageDisks[i]}, defaultErr: err}
+		storageDisks[i] = &naughtyDisk{disk: &retryStorage{
+			remoteStorage:    storageDisks[i],
+			maxRetryAttempts: 1,
+			retryUnit:        time.Millisecond,
+			retryCap:         time.Millisecond * 10,
+		}, defaultErr: err}
 	}
 	return storageDisks
 }