diff --git a/xCAT-client/pods/man1/chvm.1.pod b/xCAT-client/pods/man1/chvm.1.pod
index d7d5ee6f6..85028fe26 100644
--- a/xCAT-client/pods/man1/chvm.1.pod
+++ b/xCAT-client/pods/man1/chvm.1.pod
@@ -240,7 +240,7 @@ Deregister the Hard disk but leave the backing files.  Multiple can be done with
 
 =item B<--mem> I<memory>
 
-Set the memory, defaults to MB.
+Set the memory size for kvm/vmware virtual machines, default unit is MB. Specify in MB or append K for KB, M for MB, or G for GB.
 
 =item B<-p> I<disk>
 
diff --git a/xCAT-client/pods/man1/mkvm.1.pod b/xCAT-client/pods/man1/mkvm.1.pod
index 238e4426e..27598067e 100644
--- a/xCAT-client/pods/man1/mkvm.1.pod
+++ b/xCAT-client/pods/man1/mkvm.1.pod
@@ -106,7 +106,7 @@ The partition name of the source.
 
 =item B<--mem>
 
-Memory size for the kvm/vmware virtual machine being created. Specify units in MB (default) or append K for KB, M for MB, or G for GB.
+Set the memory size for kvm/vmware virtual machines, default unit is MB. Specify in MB or append K for KB, M for MB, or G for GB.
 
 =item B<-p>
 
@@ -114,7 +114,7 @@ The file that contains the profiles for the source partitions.
 
 =item B<-s|--size>
 
-Storage size for the kvm/vmware virtual machine being created. Specify units in GB (default) or append K for KB, M for MB, G for GB.
+Set the storage size for kvm/vmware virtual machines, default unit is GB. Specify in GB or append K for KB, M for MB, G for GB.
 
 =item B<-v|--version>