Some noob's installation questiions

[mefisto]

Greetings all,

I was able to install OpenBSD v. 7 on a MacBook. The X-based applications, LibreOffice, Firefox, etc. are rather sluggish, which I attribute to the older 5400 RPM hard-drive and 1 GB RAM. However, I am rather impressed, so I intend to replace the hard-drive with SSD, acquire more memory, and reinstall the system.

Being rather new to OpenBSD, I have a few questions, and answers to which that I was unable to find:

1. During the installation, a message appeared stating that the bsd.mp kernel is being installed. However, the FAQ suggest that the bsdkernel is required. Thus, I concluded that I should selet both the bsd and bsd.mp. Is this correct?

2. During the installation, one must partition the hard-drive; first on the Master Boot Record (MBR) level and then on the filesystem level. Since I selected to use whole disk, the MBR partitioning is using (only) the #3 partition, and since I knew no better, I let the installer suggest the filesystem partitioning of that partition, which appears to be based on the hard-drive size.

Can OpenBSD work over the MBR boundaries? That is, could one move the /home to a different MBR partition?

How does one select the sizes of the /, /var, and /usr for, e.g., a 256 GB hard drive, on a laptop that will mostly be used for office related tasks, e.g., using LibreOffice, e-mail, browser etc., so that one does not run of spaces on these partitions?

All I was able to find was, that such is based on experience, which, of course is a useless answer for a noob.

3. If one decides to re-install instead of upgrade transitioning from one version to another, how does on preserve the data in /home, since it appears that the installer will attempt to re-partition the drive?

Kindest regards,

M

[jggimi]

Welcome back.

Originally Posted by mefisto

1. During the installation, a message appeared stating that the bsd.mp kernel is being installed. However, the FAQ suggest that the bsdkernel is required. Thus, I concluded that I should selet both the bsd and bsd.mp. Is this correct?

It's a good idea to have both. In the event a problem occurs with the GENERIC.MP kernel, you can always boot the GENERIC kernel to see if it circumvents the problem. During an mp install, the file "bsd" will be renamed "bsd.sp" and the file "bsd.mp" will be renamed "bsd" -- so you can always boot the GENERIC single-processor kernel by selecting "bsd.sp" at the boot> prompt.

2. ... I let the installer suggest the filesystem partitioning of that partition, which appears to be based on the hard-drive size.

These automatic partition allocations are discussed in detail in the disklabel(8) man page.

Can OpenBSD work over the MBR boundaries? That is, could one move the /home to a different MBR partition?

Yes and no. Yes, the boundaries can be altered with the disklabel(8) interactive "b" command. This is useful to be able to assign a partition to a "foreign" filesystem. And no, it should not be used in an attempt to have multiple OpenBSD MBR partitions on a single drive, as this is not supported.

How does one select the sizes of the /, /var, and /usr for, e.g., a 256 GB hard drive, on a laptop that will mostly be used for office related tasks, e.g., using LibreOffice, e-mail, browser etc., so that one does not run of spaces on these partitions?

The disklabel(8) man page I mentioned above describes the use of the interactive partition editor.

All I was able to find was, that such is based on experience, which, of course is a useless answer for a noob.

But it happens to be true. YOUR personal blend of applications and storage needs are unique to you. The automatic allocations are a great starting point for any noob.

3. If one decides to re-install instead of upgrade transitioning from one version to another, how does on preserve the data in /home, since it appears that the installer will attempt to re-partition the drive?

BACK IT UP, then restore. Don't hope you won't make a mistake. You would have to a) record the exact starting LBA and length of the partition, and b) leave it unallocated during the new installation, c) post-installation, manually add the partition to the disklabel and then to your fstab(5) table. There are many ways this can go wrong for an experienced OpenBSD admin as well as any self-professed noob.

[mefisto]

Hi jggmi,

thank you for the reply.

That is a very good point about having both the bsd and the bsd.mp; will keep it that way in the final installation.

I will stick with the automatic install for now.

I do backup my data, I like them. But it is rather disappointing that reinstall wipes the entire disk. But, i guess this is an MBR partitioning limitation.

Kindest regards,

M

[jggimi]

Originally Posted by mefisto

... reinstall wipes the entire disk.

As noted above, you can manually work to prevent this for a particular partition. But mistakes can easily be made, and anyone who is (or describes themselves as) a "noob" will have an increased risk of failure.

But, i guess this is an MBR partitioning limitation.

No, it's an issue of experience using the disklabel(8) program, combined with an install script designed to guide the user through an initial or re-install, where OpenBSD data is not retained.

The recommended and supported way of maintaining existing data is to upgrade.

It's extremely easy to upgrade. On several architectures, # sysupgrade is all that's needed, but every admin should also review the new release's Upgrade Guide first.