can't use full disk space when partitioning

[ohmpr]

hi,
I'm trying to install OpenBSD 6.9 on a 4 TB ssd but the partitioner won't let me resize disklabel partitions to use the whole fdisk partition. It shows over 3t of free space but limits my /var to 35G or so. For some reason it lets me resize my /home partition to a larger size but none of the others i have tried.

What is going on?

thanks

[jggimi]

Without any details, I have two guesses:

1. The disklabel(8) editor will prevent you from overlaying 2 or more partitions. Their starting location and length must not overlap. So, for example, if you want a partition to start at LBA x with a length y, LBA x through LBA x+y-1 must already be unallocated before you are permitted to create the partition.
2. If you have deployed an MBR, the MBR partition table is limited to 2TB (with 512-byte sector drives). Assignments beyond 2TB require using the disklabel(8) editor's "b" command to set the boundary beyond the MBR limit. This restriction does not apply to GPTs or disk drives that do not have either an MBR or a GPT.

[ohmpr]

sorry, i just now remembered i have installed already and can at least post how it partitioned then.

disklabel -p g sd0
# /dev/rsd0c:
type: SCSI
disk: SCSI disk
label: INTEL SSDPE2KX04
duid: 1f8aaffdb6281e0e
flags:
bytes/sector: 512
sectors/track: 255
tracks/cylinder: 511
sectors/cylinder: 130305
cylinders: 59967
total sectors: 7814037168 # total bytes: 3726.0G
boundstart: 1024
boundend: 7814037105
drivedata: 0

16 partitions:
# size offset fstype [fsize bsize cpg]
a: 1.0G 1024 4.2BSD 2048 16384 12960 # /
b: 16.1G 2098176 swap # none
c: 3726.0G 0 unused
d: 4.0G 35966944 4.2BSD 2048 16384 12960 # /tmp
e: 35.8G 44355552 4.2BSD 2048 16384 12960 # /var
f: 6.0G 119433120 4.2BSD 2048 16384 12960 # /usr
g: 1.0G 132016032 4.2BSD 2048 16384 12960 # /usr/X11R6
h: 20.0G 134113184 4.2BSD 2048 16384 12960 # /usr/local
i: 0.0G 64 MSDOS
j: 2.0G 176056224 4.2BSD 2048 16384 12960 # /usr/src
k: 6.0G 180250528 4.2BSD 2048 16384 12960 # /usr/obj
l: 300.0G 192833472 4.2BSD 4096 32768 26062 # /home

i used gpt, too.

i suspect it may be your #1 reason, as i was trying to edit only certain partitions, and i guess was hoping for some automagical handling of that, or some fancy assistance from the installer, or something. I will try again and create all partitions from scratch and see if it works as expected. I was hesitant to do that b/c i wasn't sure if the partition order was mandatory, what was going on with the c and i partitions(how i woulkd create those myself from scratch properly) , etc.

thanks

[ohmpr]

@jggimi thanks a lot! that was it (#1)!

i just deleted all the partitions i wanted to change, then went in order creating them fresh, and it worked great.

I knew i was doing something dumb.

[jggimi]

Because you asked about partitions "c" and "i":

• The "c" partition is reserved for the entire physical disk. It starts at LBA 0 and runs to the very last sector of the drive. You cannot change this with the disklabel(8) editor.
• When a disklabel does not yet exist on a drive, OpenBSD will scan the MBR or GPT partition table for "foreign" partition types it recognizes. It creates a virtual, in-memory disklabel and assigns them to partitions starting with partition "i". After that disklabel is written to disk, OpenBSD won't scan your MBR/GPT partition table again. In this particular case, partition "i" maps to your GPT boot partition, which is a mountable FAT filesystem.

[jggimi]

Oh, you can force a rescan of MBR/GPT partition tables for foreign file systems. The disklabel(8) -d option or the disklabel(8) editor "D" command will *reset* the disklabel to the default. It will clear the disklabel completely, then rescan the MBR or GPT table. The disklabel will only contain the "c" partition and foreign MBR/GPT partitions starting with "i". All other disklabel partitions will be deleted.

[ohmpr]

cool, thanks

[leave0]

same problem to me ,would you mind to give more details about how to fix that?

[ohmpr]

i don't know how much help i can be, as i don't remember the exact details, but feel free to describe more precisely what you're having trouble with and maybe someone can help.

Here's how i remember it:

i let the automatic partitioner partition the disk, i wrote down how it partitioned everything. Then i wrote down how i wanted the partitions to be (labels, sizes, mount points). You may not have to do all that writing, i'm just new to OpenBSD and wanted to make sure i didn't screw everything up. Then i deleted every partition except c and swap (IIRC). Then i created the partitions the way i wanted them to be (size, label, mount points, whatever). Then i was able to use all the space.

[leave0]

thank you