OpenBSD 6.7 installation add (gpt) partition?

[tingo]

So I'm trying to install OpenBSD 6.7 (amd64) here. I think the last time I installed OpenBSD was 6.0 or something. Much has changed.
Anyway, I'm installing on a machine which has a few operating systems already, so the hard drive (gpt / guid) already has an EFI partition, and a few others. No problem, I'll just add another gpt partition for OpenBSD and let it use that.

The install program dumps me into the fdisk program, which has "help", and even a manual. Great! Except that there doesn't seems to be an "add" (as in add partition) command in fdisk. Ok, let me try with the edit command then; I can say "edit 3" for example.

But - the edit command think it can start with offset at the same place as the first existing partition - that's no good. I can use the print command to see existing partitions; but it only tells me where they start and the size, not where the last partition ends.

Is there a way to add a partition without a calculator?

[PapaParrot]

I am not really sure, I have never needed a calculator to install OpenBsd, but I must admit I have not tried a "multi boot" install, I would how ever look at:
https://man.openbsd.org/fdisk and https://www.openbsd.org/faq/faq4.html

Disk Partitioning
OpenBSD can be installed in as little as 512MB, but using a device that small is something for advanced users. Until you have some experience, 8GB or more disk space is recommended.

Unlike some other operating systems, OpenBSD encourages users to split their disk into a number of partitions, rather than just one or two large ones. Some of the reasons for doing so are: ----snipt---
Read about disklabel's defaults for automatic disk allocation

The Automatic Disk allocation option is what I use, that might be of use to you :
https://man.openbsd.org/disklabel#AU...ISK_ALLOCATION
=================================================
In addition on Multi booting , the FAQ again:

https://www.openbsd.org/faq/faq4.html
Multibooting
Multibooting is having several operating systems on one computer, with some means of selecting which OS is to boot. You may want to familiarize yourself with the OpenBSD boot process before you start. A brief introduction to fdisk(8) is in the section on using OpenBSD's fdisk.

If you are adding OpenBSD to an existing system, you will probably need to create some free space before installing OpenBSD. In addition to your existing system's native tools, gparted may be useful for deleting or resizing existing partitions. Preferably use one of the four primary MBR partitions for booting OpenBSD. Extended partitions may not work.

rEFInd is reported to usually work. GRUB is reported to usually fail. In either case, you are completely on your own.

Some one else may be able to give you more details,..

[Head_on_a_Stick]

I just use gdisk (from a Linux distribution) to create a partition of type a600 to hold OpenBSD before loading the installer. It's a bit pathetic but I'm more familiar with that tool.

[fvgit]

If I'm not mistaken you can only have four partition table slots. Which is why there is no add command. You simply just edit either of 0, 1, 2, or 3.

Here's what mine looks like:

 
Disk: wd0       geometry: 19457/255/63 [312581808 Sectors]
Offset: 0       Signature: 0xAA55
            Starting         Ending         LBA Info:
 #: id      C   H   S -      C   H   S [       start:        size ]
-------------------------------------------------------------------------------
 0: EE      0   0   2 -     25 127  14 [           1:      409639 ] EFI GPT     
 1: AF     25 127  15 -   6014  25   3 [      409640:    96206848 ] MacOS X HFS+
*2: A6   6030 137  60 -  19457  53  52 [    96880640:   215699456 ] OpenBSD     
 3: 00      0   0   0 -      0   0   0 [           0:           0 ] unused

Maybe this might help (emphasis mine):

     edit #  Edit a given table entry in the memory copy of the current boot
             block.  Sizes may be adjusted in BIOS geometry mode (MBR only) or
             using sector offsets and sizes.  A unit ‘b’, ‘k’, ‘m’, or ‘g’ may
             be appended to indicate bytes, kilobytes, megabytes, or
             gigabytes.  The special size value ‘*’ will cause the partition
             to be sized to use the remainder of the disk.

[Head_on_a_Stick]

Originally Posted by fvgit

If I'm not mistaken you can only have four partition table slots

That limitation does not apply to GUID partition tables, they can accommodate 128 partitions in the default configuration and that number can be increased.

[fvgit]

I don't think OpenBSD's fdisk(1) supports this, or does it?

[jggimi]

It supports GPT partitions 0 through 127.

[fvgit]

I feel stupid now, lol. For some odd reason when looking at the manpage I saw the '#' entry under the MBR example (which lists the four slot limitation) and somehow mixed it up with that of the GPT example 36 lines further down (which doesn't list any limitation). That's what you get for sloppily jumping around between browser windows and terminal workspaces.

We really need a facepalm smiley.

[jggimi]

No, there's nothing in the manual about it. I created a test file, attached a vnode with vnconfig(8), wrote a GPT with fdisk(8), and tested the sector numbers to discover the valid sector range.

[tingo]

Since there isn't an "OpenBSD way" to do it, I simply used gpart from FreeBSD to create the partition, like so

gpart add -t openbsd-data -s 60G da0

. That worked nicely.