New Tool: lsds – List All Linux Block Devices and Settings in One Place

Summary

When dealing with disks and I/O things on Linux, you’d regularly run commands like lsblk, lsscsi, nvme list, etc. All of them tend to report a different set of information, so I ended up running multiple commands and correlating their output based on the device name or number. And then I had to run commands like these, to get extra info about the current OS-level configuration settings for specific disks: grep . /sys/class/block/sd*/device/queue_depth grep . /sys/class/block/*/queue/nr_requests The above commands would show the hardware-advertised device queue depth and the OS block device level (software) queue depth. I finally had enough and created a single Python program lsds for showing all interesting bits for a disk in one place. The lsds tool does not execute any other commands under the hood, it just reads the relevant info from sysfs /sys/class/blocks/... directories directly. See my 0x.tools toolset for more Linux performance & troubleshooting tools. Here’s an output from my machine with 21 SSDs in it. You may need to scroll right to see the full output: $ lsds DEVNAME MAJ:MIN SIZE TYPE SCHED ROT MODEL QDEPTH NR_RQ WCACHE nvme0n1 259:4 931.5 GiB NVMeDisk none 0 Samsung SSD 9100 PRO 1TB - 1023 write back nvme10n1 259:21 465.8 GiB NVMeDisk none 0 Samsung SSD 980 PRO 500GB - 1023 write back nvme11n1 259:22 465.8 GiB NVMeDisk none 0 Samsung SSD 980 PRO 500GB - 1023 write back nvme12n1 259:9 931.5 GiB NVMeDisk none 0 Samsung SSD 980 PRO 1TB - 1023 write back nvme13n1 259:16 931.5 GiB NVMeDisk none 0 Samsung SSD 980 PRO 1TB - 1023 write back nvme14n1 259:8 931.5 GiB NVMeDisk none 0 Samsung SSD 980 PRO 1TB - 1023 write back nvme15n1 259:15 931.5 GiB NVMeDisk none 0 Samsung SSD 980 PRO 1TB - 1023 write back nvme16n1 259:12 1863.0 GiB NVMeDisk none 0 T-FORCE TM8FF1002T - 1023 write back nvme17n1 259:11 1863.0 GiB NVMeDisk none 0 T-FORCE TM8FF1002T - 1023 write back nvme18n1 259:13 1863.0 GiB NVMeDisk none 0 T-FORCE TM8FF1002T - 1023 write back nvme19n1 259:14 1863...