diff --git a/sdk/data/stream/extent_flash_cache.go b/sdk/data/stream/extent_flash_cache.go
index d1353b3ce..a7c3e780a 100644
--- a/sdk/data/stream/extent_flash_cache.go
+++ b/sdk/data/stream/extent_flash_cache.go
@@ -29,6 +29,7 @@ import (
 	"github.com/cubefs/cubefs/sdk/master"
 	"github.com/cubefs/cubefs/sdk/meta"
 	"github.com/cubefs/cubefs/util"
+	"github.com/cubefs/cubefs/util/auditlog"
 	"github.com/cubefs/cubefs/util/bloom"
 	"github.com/cubefs/cubefs/util/btree"
 	"github.com/cubefs/cubefs/util/errors"
@@ -587,12 +588,14 @@ func (rc *RemoteCache) ClassifyHostsByAvgDelay(fgID uint64, hosts []string) (sor
 		}
 		if avgTime <= time.Duration(0) {
 			sortedHosts[UnknownZoneRank] = append(sortedHosts[UnknownZoneRank], host)
+			auditlog.LogOpMsg("ClassifyHostsByAvgDelay", fmt.Sprintf("add host %v to unknown region", host), nil)
 		} else if avgTime <= sameZoneTimeout {
 			sortedHosts[SameZoneRank] = append(sortedHosts[SameZoneRank], host)
 		} else if avgTime <= sameRegionTimeout {
 			sortedHosts[SameRegionRank] = append(sortedHosts[SameRegionRank], host)
 		} else {
 			sortedHosts[CrossRegionRank] = append(sortedHosts[CrossRegionRank], host)
+			auditlog.LogOpMsg("ClassifyHostsByAvgDelay", fmt.Sprintf("add host %v to cross region by time %v", host, avgTime.String()), nil)
 		}
 	}
 	log.LogInfof("ClassifyHostsByAvgDelay: fgID(%v) sortedHost:%v", fgID, sortedHosts)
diff --git a/util/auditlog/auditlog.go b/util/auditlog/auditlog.go
index e98baf19f..588949793 100644
--- a/util/auditlog/auditlog.go
+++ b/util/auditlog/auditlog.go
@@ -349,6 +349,17 @@ func (a *Audit) formatMasterAudit(op, msg string, err error) (str string) {
 	return
 }
 
+func (a *Audit) formatOpAudit(op, msg string, err error) (str string) {
+	var errStr string
+	if err != nil {
+		errStr = err.Error()
+	} else {
+		errStr = "nil"
+	}
+	str = fmt.Sprintf("%v, %v, %v, ERR: %v", a.formatCommonHeader(), op, msg, errStr)
+	return
+}
+
 func (a *Audit) formatMasterLog(op, msg string, err error) {
 	if entry := a.formatMasterAudit(op, msg, err); entry != "" {
 		if a.prefix != nil {
@@ -358,6 +369,15 @@ func (a *Audit) formatMasterLog(op, msg string, err error) {
 	}
 }
 
+func (a *Audit) formatOpLog(op, msg string, err error) {
+	if entry := a.formatOpAudit(op, msg, err); entry != "" {
+		if a.prefix != nil {
+			entry = fmt.Sprintf("%s%s", a.prefix.String(), entry)
+		}
+		a.AddLog(entry)
+	}
+}
+
 func (a *Audit) LogResetDpDecommission(status string, src string, disk string, dpId uint64, dst string) {
 	status = fmt.Sprintf("Prev: %v", status)
 	src = fmt.Sprintf("SrcAddr: %v", src)
@@ -767,6 +787,15 @@ func isPathSafe(filePath string) bool {
 	return match
 }
 
+func LogOpMsg(op, msg string, err error) {
+	gAdtMutex.RLock()
+	defer gAdtMutex.RUnlock()
+	if gAdt == nil {
+		return
+	}
+	gAdt.formatOpLog(op, msg, err)
+}
+
 func LogMasterOp(op, msg string, err error) {
 	gAdtMutex.RLock()
 	defer gAdtMutex.RUnlock()