Comment 11 for bug 1658524

Happens also on byobu version 5.112 (tmux 2.8), the one that comes with the up-to-date Raspberry Pi OS / Raspbian (tested on both a RPi2 and a RPi4).

iostat and such seem to work properly, i.e. on the RPi4 with SSD (USB) boot and 2 extra HDD (USB) drives:

iostat -d -m -h
Linux 5.4.58-v7l+ (raspberrypi) 21/08/20 _armv7l_ (4 CPU)

      tps MB_read/s MB_wrtn/s MB_read MB_wrtn Device
     1,21 21,2k 56,3k 1,7G 4,4G sda
    24,15 1,0k 10,4M 77,3M 828,2G sdb
   165,44 10,0M 0,0k 795,3G 128,0k sdc
     0,01 0,0k 0,0k 2,2M 544,0k zram0
     0,01 0,0k 0,0k 2,2M 432,0k zram1
     0,01 0,0k 0,0k 2,2M 304,0k zram2
     0,01 0,0k 0,0k 2,2M 332,0k zram3

for disk in /sys/block/* ; do echo "$disk/stat:" ; cat "$disk/stat" ; done
/sys/block/loop0/stat:
       0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
(...)
/sys/block/loop7/stat:
       0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
/sys/block/ram0/stat:
       0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
(...)
/sys/block/ram9/stat:
       0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
/sys/block/sda/stat:
   51449 41174 3460329 130396 47218 45135 9198594 421216 0 227110 369490 0 0 0 0
/sys/block/sdb/stat:
    7166 6427 158395 189787 1966305 5378542 1736823012 194266939 0 7936480 184611430 0 0 0 0
/sys/block/sdc/stat:
13522314 148515 1667943478 48177309 17 15 256 26 0 26246130 1056690 0 0 0 0
/sys/block/zram0/stat:
     557 0 4456 0 136 0 1088 10 0 540 10 0 0 0 0
(...)
/sys/block/zram3/stat:
     561 0 4488 0 83 0 664 10 0 390 10 0 0 0 0