possible size conversion issue

[daniejstriata]

Hi,

using LFS 1.0.0. When I compare this output to that from df and df -h the output from lfs seems wrong. total size is not 13G and the used from df is 8.5G but 9.1G on LFS.

┌──┬─────┬──────────────┬────┬────┬────┬─────────┬─────┬────┬──────────────────┐
│id│ dev │  filesystem  │disk│type│used│  use%   │avail│size│mount point       │
├──┼─────┼──────────────┼────┼────┼────┼─────────┼─────┼────┼──────────────────┤
│38│259:8│/dev/nvme0n1p1│SSD │xfs │9.1G│71% ███▌ │ 3.8G│13G │/                 │
│43│259:4│/dev/nvme5n1  │SSD │xfs │127M│ 1%      │  12G│12G │/var/local1       │
│44│259:6│/dev/nvme7n1  │SSD │xfs │106M│ 1%      │  11G│11G │/var/store1       │
│46│259:0│/dev/nvme1n1  │SSD │xfs │7.4G│77% ███▉ │ 2.3G│9.7G│/usr/local/Store  │
│45│259:1│/dev/nvme2n1  │SSD │xfs │518M│16% ▊    │ 2.7G│3.2G│/var/log          │
│47│259:5│/dev/nvme6n1  │SSD │xfs │306M│14% ▊    │ 1.8G│2.1G│/tmp              │
│42│259:2│/dev/nvme4n1  │SSD │xfs │ 36M│ 3% ▏    │ 1.0G│1.1G│/home             │
└──┴─────┴──────────────┴────┴────┴────┴─────────┴─────┴────┴──────────────────┘

→ df | grep /$
/dev/nvme0n1p1  12570604 8865848   3704756  71% /

→ df -h | grep /$
/dev/nvme0n1p1   12G  8.5G  3.6G  71% /

Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        7.8G     0  7.8G   0% /dev
tmpfs           7.8G   12K  7.8G   1% /dev/shm
tmpfs           7.8G  900K  7.8G   1% /run
tmpfs           7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/nvme0n1p1   12G  8.5G  3.6G  71% /
/dev/nvme1n1    9.0G  6.9G  2.2G  77% /usr/local/Store
/dev/nvme7n1     10G  101M  9.9G   1% /var/store1
/dev/nvme5n1     11G  122M   11G   2% /var/local1
/dev/nvme4n1   1014M   35M  980M   4% /home
/dev/nvme6n1    2.0G  292M  1.8G  15% /tmp
/dev/nvme2n1    3.0G  489M  2.6G  16% /var/log
tmpfs           1.6G     0  1.6G   0% /run/user/0
tmpfs           1.6G     0  1.6G   0% /run/user/1002

[Canop]

To compare with lfs, don't use df -h (which uses the old 1024 based unit) but df -H which uses the ISO 1000 based unit.

[daniejstriata]

AWS EC2 shows their sizes as GiB. Then to use the json output I have to do conversions in any case. Will it be possible to add a switch to print out the sizes differently as an option please?

[Canop]

Will it be possible to add a switch to print out the sizes differently as an option please?

You mean when you output as JSON ?

[Canop]

In JSON I could even output the two values, there's no real cost.

[daniejstriata]

Can the switch be available for regular use and json output?

I had a look at df again. I've always used df -h. Interesting that df -h and df -H both prints G or M without distinction. I'm using EC2 which uses GiB and ideally the sizes from EC2 should match the sizes from the host without needing to convert in between.

I had a search on their mailing list and found this:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=47023#16
Found this statements from LA Walsh

Side rant:
 Using decimal prefixes with a binary unit (1B=2**3 bits)
 defeats the purpose of using a common multiplier for metric.
 Since computers use base-2, similar prefixes should be used.
 Just because the disk-industry bought and paid for the
 ruling to use base-10 doesn't mean that memory comes in
 units of 1-million, 1-billion or 1-trillion bytes or
 that disk space is organized in decimal units.

I mailed the group and asked if they could print GB and GiB accordingly.

[Canop]

I won't personally go and have a fight with the old guys still arguing that base-2 makes sense for units...

If you want to avoid ambiguity when reading the JSON, just multiply blocks by bsize, the result will be in bytes. df can output in bytes too.

[daniejstriata]

@Canop Will it be still be possible to update file-size to do both conventions and incorporate those choices in lfs? The info from LFS is great but as soon as the info leaves the box other processes don't use ISO. As example the technicians here would ideally share the print from LFS as it is so neat and tidy in hangouts when busy troubleshooting but then infrastructure sees different sizes in AWS causing a small bit of confusion.

[Canop]

There could be a launch argument, yes, and then the label of the column would be different.

[Canop]

Maybe --unit SI (default) and --unit binary.

[daniejstriata]

That can work.

[Canop]

Not yet released but testable from master.

Not sure whether I'll keep the ugly "i" everywhere.

[daniejstriata]

The GNU coreutils guys seems to have decided to only print the G for ISO and Binary back when a terminal screen's real-estate was limited. I'd print the "i".

[Canop]

I noticed you were concerned with alignment too.
So... a subtle change...

[daniejstriata]

Is this a before and after screenshot? The headers use different words between the 2 commands you ran. free vs available and used vs use. Used and Free seems correct.

[Canop]

That was the "subtle change" (not completely decided): when units is "binary", picking different words so that the alignment is better (you have one more character usually with the 'i').

EDIT: This would only add confusion, reverting to const labels.