| 1 | major number | |
| 2 | minor number | |
| 3 | device name | |
| 4 | reads completed successfully | |
| 5 | reads merged | |
| 6 | sectors read | |
| 7 | time spent reading (ms) | |
| 8 | writes completed | |
| 9 | writes merged | |
| 10 | sectors written | |
| 11 | time spent writing (ms) | |
| 12 | I/Os currently in progress | The only (statitical) value that is not cumulative since startup. |
| 13 | time spent doing I/Os (ms) | |
| 14 | weighted time spent doing I/Os (ms) | |
| 15 | discards completed successfully | Added in Linux 4.18+ for discard tracking. |
| 16 | discards merged | Added in Linux 4.18+ for discard tracking. |
| 17 | sectors discarded | Added in Linux 4.18+ for discard tracking. |
| 18 | time spent discarding | Added in Linux 4.18+ for discard tracking. |
| 19 | flush requests completed successfully | Added in Linux 5.5+ for flush requests |
| 20 | time spent flushing | Added in Linux 5.5+ for flush requests |