Fix 6181/6182 (#6183)

* set larger buf size for LogBuffer

* jump to next day when no more entry found

* Update weed/filer/filer_notify_read.go

---------

Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>

weed/server/filer_grpc_server_sub_meta.go

@@ -2,11 +2,12 @@ package weed_server
 
 import (
 	"fmt"
-	"github.com/seaweedfs/seaweedfs/weed/stats"
 	"strings"
 	"sync/atomic"
 	"time"
 
+	"github.com/seaweedfs/seaweedfs/weed/stats"
+
 	"google.golang.org/protobuf/proto"
 
 	"github.com/seaweedfs/seaweedfs/weed/filer"
@@ -62,8 +63,19 @@ func (fs *FilerServer) SubscribeMetadata(req *filer_pb.SubscribeMetadataRequest,
 			return nil
 		}
 
+		glog.V(4).Infof("processed to %v: %v", clientName, processedTsNs)
 		if processedTsNs != 0 {
 			lastReadTime = log_buffer.NewMessagePosition(processedTsNs, -2)
+		} else {
+			nextDayTs := util.GetNextDayTsNano(lastReadTime.UnixNano())
+			position := log_buffer.NewMessagePosition(nextDayTs, -2)
+			found, err := fs.filer.HasPersistedLogFiles(position)
+			if err != nil {
+				return fmt.Errorf("checking persisted log files: %v", err)
+			}
+			if found {
+				lastReadTime = position
+			}
 		}
 
 		glog.V(4).Infof("read in memory %v aggregated subscribe %s from %+v", clientName, req.PathPrefix, lastReadTime)
@@ -72,10 +84,7 @@ func (fs *FilerServer) SubscribeMetadata(req *filer_pb.SubscribeMetadataRequest,
 			fs.filer.MetaAggregator.ListenersLock.Lock()
 			fs.filer.MetaAggregator.ListenersCond.Wait()
 			fs.filer.MetaAggregator.ListenersLock.Unlock()
-			if !fs.hasClient(req.ClientId, req.ClientEpoch) {
-				return false
-			}
-			return true
+			return fs.hasClient(req.ClientId, req.ClientEpoch)
 		}, eachLogEntryFn)
 		if readInMemoryLogErr != nil {
 			if readInMemoryLogErr == log_buffer.ResumeFromDiskError {