root@pve1:~# hdparm -Tt /dev/sdc

/dev/sdc:
 Timing cached reads:   ^[[A41074 MB in  1.98 seconds = 20694.18 MB/sec
^C
root@pve1:~# hdparm -Tt /dev/sdc

/dev/sdc:
 Timing cached reads:   42898 MB in  1.98 seconds = 21618.60 MB/sec
 Timing buffered disk reads: 482 MB in  3.01 seconds = 160.12 MB/sec
root@pve1:~# hdparm -Tt /dev/sdd

/dev/sdd:
 Timing cached reads:   41214 MB in  1.98 seconds = 20767.21 MB/sec
 Timing buffered disk reads: 394 MB in  3.94 seconds = 100.02 MB/sec
root@pve1:~# hdparm -Tt /dev/sde

/dev/sde:
 Timing cached reads:     2 MB in  2.18 seconds = 941.02 kB/sec
 Timing buffered disk reads: 218 MB in  3.05 seconds =  71.57 MB/sec
root@pve1:~# hdparm -Tt /dev/sdf

/dev/sdf:
 Timing cached reads:   40918 MB in  1.98 seconds = 20614.77 MB/sec
 Timing buffered disk reads: 578 MB in  3.02 seconds = 191.65 MB/sec