Why at least 4 cylinder groups?

[Norbert Koch]

Hello.

In an embedded system I am having a rather
small (static) ram disk of about 1.5MB,
formatted as UFS(1).

Under FreeBSD 4 dumpfs shows me there is
1 cylinder group.

Under FreeBSD 9 and 10 I see 4 cylinder groups.

4 is hard coded as the minimum value in ufs/ffs/fs.h. Why?

Is there any technical reason not to have less
than 4 cylinder groups?

For my application the wasted 188KB make a difference.

Thank you,
Norbert Koch