I think this bug is your case. From what I see from the output, you have enough memory (note the cached 14 GB or so), no I/O issues, but you have xen-related processes running. This make me think it is a bug.
I think this bug is your case. From what I see from the output, you have enough memory (note the cached 14 GB or so), no I/O issues, but you have xen-related processes running. This make me think it is a bug.