Should ZFS members be detected by lsblk?

[TheLillo]

Is there a way to use lsblk in a Linux system on ZFS that shows information like mountpoint, members etc?

[darkralts]

i want to know

[rincebrain]

That's kind of like asking for the mountpoint of an LVM volume group - the answer may be, depending on what you're doing with it, "none", "one" ,or "many".

That said, I've never looked at what lsblk reports for LVM and similar, so if it can do it for that, conceivably one could convince it to do that for ZFS.

[LunarLambda]

lsblk can report LVs and their mountpoints, nested underneath their backing devices (PVs).

Here's an example I pulled from a server:

NAME                 MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINTS
sda                    8:0    0  320G  0 disk
├─sda1                 8:1    0    2M  0 part
├─sda2                 8:2    0    1G  0 part  /boot
└─sda3                 8:3    0  319G  0 part
  └─sda3_crypt       254:0    0  319G  0 crypt
    ├─vg1-swap     254:1    0  7.4G  0 lvm   [SWAP]
    ├─vg1-root     254:2    0  7.4G  0 lvm   /
    ├─vg1-machines 254:3    0  220G  0 lvm   /var/lib/machines

If a VG has multiple PVs, I believe lsblk will show the LVs underneath each PV in the default view, which can lead to some duplicated output, in a similar way as it does for mdraid devices.

[amotin]

In the examples of mdraid and lvm it seems to be a block layer on top of block layer, and then for the last block layer reported its mount point for traditional file systems. I don't know how it gets the mount points, but I guess not by reading the disks, but somehow reading superblock information form kernel to associate it with the disks. Whether it can be done from ZFS, I don't know, but considering that many pools have many datasets and many vdevs, I am not sure the output would end up useful.

[LunarLambda]

I think at minimum for the kernel to associate some sort of blockdev with a mountpoint (and thus have it appear in lsblk) it would need to not show up as nodev in /proc/filesystems

EDIT: seems to be mtab / /proc/mounts based somehow?

https://github.com/util-linux/util-linux/blob/master/misc-utils/lsblk-mnt.c