[RndTbl] Getting disk sizes of mountpoints

[Kevin McGregor]

Fair question. On the same system, df -h gives:
Filesystem            Size  Used Avail Use% Mounted on
udev                  465M     0  465M   0% /dev
tmpfs                  99M  7.8M   91M   8% /run
/dev/mapper/vg0-root   15G  3.3G   12G  22% /
tmpfs                 493M     0  493M   0% /dev/shm
tmpfs                 5.0M     0  5.0M   0% /run/lock
tmpfs                 493M     0  493M   0% /sys/fs/cgroup
/dev/mapper/vg1-data   98G   61M   93G   1% /mnt/data
/dev/mapper/vg0-var   5.0G  956M  4.1G  19% /var
tmpfs                  99M     0   99M   0% /run/user/1000

Where '/' and 'var' are correct, but /mnt/data shows as 98G instead of
100G. I'm looking for the disk sizes, not the file system sizes.

This is actually a VM, and I can get the exact disk sizes from VMware...
but not the mount points. And since / and /var are on the same disk, the
VMware info lacks the detail I need.

Major device 253 seems to be used for LVM devices, so assuming that misses
things like "sda2                8:2    0    2G  0 part /boot", which I'd
also like to account for. Another system, for example, has
NAME                MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda                   8:0    0   50G  0 disk
├─sda1                8:1    0    1M  0 part
├─sda2                8:2    0    2G  0 part /boot
└─sda3                8:3    0   48G  0 part
  ├─ubuntu--vg-root 253:0    0   24G  0 lvm  /
  └─ubuntu--vg-var  253:1    0   24G  0 lvm  /var
sr0                  11:0    1 1024M  0 rom

And from that I would want
/boot 2G
/ 24G
/var 24G
which adds up to 50G (sda)

lsblk -e 7 | grep '/' | awk '{ print $NF, $4 }'
basically works (for my sample of two systems), but I don't know how
reliable assuming grep '/' is going to be for what I want.


On Wed, Feb 21, 2024 at 4:44 PM Vijay Sankar <vsankar at foretell.ca> wrote:

> Doesn’t df -h give that info? Sorry if I misunderstood your question.
>
> Sent from my iPhone
>
> On Feb 21, 2024, at 16:36, Kevin McGregor <kevin.a.mcgregor at gmail.com>
> wrote:
>
> 
> With 'lsblk' I can get something like this:
> NAME         MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
> sda            8:0    0   20G  0 disk
> └─sda1         8:1    0   20G  0 part
>   ├─vg0-root 253:0    0   15G  0 lvm  /
>   └─vg0-var  253:1    0    5G  0 lvm  /var
> sdb            8:16   0  100G  0 disk
> └─sdb1         8:17   0  100G  0 part
>   └─vg1-data 253:2    0  100G  0 lvm  /mnt/data
> sr0           11:0    1 1024M  0 rom
>
> What I'm looking for is output like:
> / 15G
> /var 5G
> /mnt/data 100G
>
> So I just want the size of the block devices which are actually mounted.
> I'm wondering what is the most reliable way to produce the second output. I
> can just grep for 'lvm', but I can't guarantee the mounts are all LVM type.
> I can grep for ' 253:', but is the 253 going to be reliable? What does 253
> even mean?
>
> From https://www.kernel.org/doc/html/latest/admin-guide/devices.html :
>
> 240-254 block  LOCAL/EXPERIMENTAL USE
>                 Allocated for local/experimental use.  For devices not
>                 assigned official numbers, these ranges should be
>                 used in order to avoid conflicting with future assignments.
>
> ... which isn't encouraging. Is that list outdated? grep for '/'s?
>
> _______________________________________________
> Roundtable mailing list
> Roundtable at muug.ca
> https://muug.ca/mailman/listinfo/roundtable
>
> _______________________________________________
> Roundtable mailing list
> Roundtable at muug.ca
> https://muug.ca/mailman/listinfo/roundtable
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://muug.ca/pipermail/roundtable/attachments/20240221/e0c8c40a/attachment-0001.htm>