This high load may be due to the "nightly" rsync you see below:
Looks more like a runaway python to me.
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1927 www-data 39 19 1090m 740m 3596 S 0 12.1 425:43.54 python
2691 nobody 20 0 109m 58m 33m S 0 1.0 0:02.24 git
10840 root 20 0 107m 48m 1556 D 1 0.8 1:19.83 rsync
(BTW, not to be teaching my betters, but I suggest "top c" to show
command lines and not just names.)
But anyway ... Michael, what is the rsync job doing? It is easy to make
it consume less resources in exchange for more time, --bwlimit=100
(Kbytes/sec) or whatever number turns out to be good. It should
probably also be running with nice -19.