Dangerously dedicated mode with FreeBSD 10.1

[Rostislav Krasny]

On Sat, Nov 22, 2014 at 8:02 PM, Nathan Whitehorn
<nwhitehorn at freebsd.org> wrote:
>
> On 11/22/14 06:15, Rostislav Krasny wrote:
>>
>> Unfortunately disk partitioning of bsdinstall(8) isn't precise and
>> isn't informative. Disk partitioning by sysinstall(8) was much better
>> in this sense. With bsdinstall(8) I don't see how much disk space is
>> left unpartitioned and where. Also I don't see where partitions start
>> and what are their sizes in LBA units of measurement. By default
>> bsdinstall(8) offers one huge partition for the root mount and a few
>> hundreds of megabytes for swap partition after the root one. If don't
>> like the offered partition sizes and want to create the same
>> partitions manually (with slightly different sizes) I can't do it
>> because of the precision flaw. Defining the root partitions in GB
>> units with a size close to the whole disk size doesn't left any free
>> space for the small swap partition. And if I create a swap partition
>> before the root one I get an unbootable system.
>
>
> It isn't meant to provide partitioning at the level of detail where you are
> specifying the start position in blocks. Why do you need that? If you want
> that, gpart at the command line is a much better tool. You can tell
> bsdinstall to use previously created partitions, of course, and you can also
> specify partition sizes to arbitrary precision. If you want sub-GB
> partitioning, specify the size in MB, or KB, or blocks. You are free to do
> any of these things.

I know that I can specify MB or KB but it doesn't help at all.
bsdinstall(8) doesn't show the exact size of the disk. In my case it
shows 13 GB, that is a rounded size of 26564832 sectors (26564832 *
512 bytes =~ 12.667GB). It also doesn't show how much space is left
free. I wanted to divide all this disk space into one big UFS
partition, one 256MB swap partition and left no free space. Partedit
of the bsdinstall(8) is useless in this task.

>> Another problem with bsdinstall(8) partitioning is an inability of
>> using already partitioned disk. This is what I've tried first. In this
>> case I was need to define the mount points of the existing partitions.
>> It's easy to do (since I have a backup of my previous /etc/fstab) but
>> then bsdinstall(8) didn't ask me if I want to re-format those
>> partitions. Then the whole installation failed at the beginning of
>> base.txz extracting (the first txz package). I'm almost sure it failed
>> because it tried to extract the base.txz over existing filesystem of
>> my previous FreeBSD 7.4 system.
>>
> It can use an already partitioned disk, which seems to be your problem here
> in fact. Like the partition editor in every other OS, it assumes that if you
> just specify the mount point for a partition, you don't want to erase it.
> Erasing existing partitions is an extremely unfriendly thing to do. You can
> re-initialize it by changing any non-mountpoint property of the partition or
> from the command line.

Installer should ask the user: does he want to re-format the chosen
partition. Without this option the whole installation may fail, like
in my case. If those partitions are system and have previous version
of FreeBSD or any other OS installed on them, there is a high
probability that the user really wants to re-format them. This is the
usual behavior of other OS installers.