diff --git a/lego/sys/log/options.go b/lego/sys/log/options.go
index c265cf9bd..ca1fbfcc5 100644
--- a/lego/sys/log/options.go
+++ b/lego/sys/log/options.go
@@ -128,6 +128,7 @@ func newOptionsByOption(opts ...Option) (options *Options, err error) {
 		CupTimeTime:  24,
 		MaxAgeTime:   7,
 		MaxBackups:   250,
+		MaxSize:      100 * 1024 * 1024,
 		Compress:     false,
 		Encoder:      TextEncoder,
 		CallerSkip:   3,