swap partition

Polytropon freebsd at edvax.de
Thu Dec 29 12:08:52 UTC 2016

On Thu, 29 Dec 2016 06:53:40 -0500, Stari Karp wrote:
> I like to increase swap partition but I am scary to screw up my system.
> FreeBSD is installed on iMac (Mountain Lion).
> gpart show
> =>        34  1953525101  ada0  GPT  (932G)
>           34           6        - free -  (3.0K)
>           40      409600     1  efi  (200M)
>       409640  1216587112     2  apple-hfs  (580G)
>   1216996752     1269536     3  apple-boot  (620M)
>   1218266288        1024     4  freebsd-boot  (512K)
>   1218267312   727710720     5  freebsd-ufs  (347G)
>   1945978032     7547102     6  freebsd-swap  (3.6G)
>   1953525134           1        - free -  (512B)
> What I planning to do:
> Boot to OS X and than decrease apple-hfs partition for 64 GB.
> Than boot to FreeBSD (single user) and:
> swapoff -a
> gpart resize -i6 ada0
> swapon -a
> Do I need to use gpart resize -i6 -s 64G ada0 or gpart will find empty
> space and use it, please?

I don't think this is possible. Partitions have to be coherent
disk space. If I read your current layout correctly, shrinking
ada0p2 (apple-hfs) would leave a "hole" before ada0p3 (apple-boot),
but your swap space is ada0p6.

However, you can add a second swap space (and maybe even ignore
your existing one), so the final layout could be this:

	ada0p1  efi  (200M)
	ada0p2  apple-hfs  (580G - 64G)	<--- shrink
	ada0p3  freebsd-swap  (64G)	<--- create in "hole"
	ada0p4  apple-boot  (620M)
	ada0p5  freebsd-boot  (512K)
	ada0p6  freebsd-ufs  (347G)
	ada0p7  freebsd-swap  (3.6G)	<--- maybe ignore

However, I don't have experience regarding partitioning on
Mac OS X systems, but from a "logic point of view", this sounds
reasonable. I'm also not sure if repartitioning will cause
partition numbers to change, or if the offset and size will
be assigned accordingly (so the new partition would become

> Should I format on OS X empty space to FAT?

No, leave it untouched, "empty space", unallocated. A swap
partition doesn't need a file system, in fact, is _has to be_
void of a file system.

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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