Fast Filesystem defaults

[Steven Bellovin]

> >On rp07s, it's quite easy to run out of i-nodes; there are *many* blocks per
> >cylinder group, and 2K i-nodes just doesn't make it.  We have to override
> >the cylinder group size on our rp07s just to get enough i-nodes.
> 
> I don't quite understand....  From man 8 newfs:
> 
> 	.B \-i number of bytes per inode
> 	This specifies the density of inodes in the file system.
> 	The default is to create an inode for each 2048 bytes of data space.
> 	If fewer inodes are desired, a larger number should be used;
> 	to create more inodes a smaller number should be given.
> 
> If you have one inode per 2K of data space, then it doesn't matter
> how many blocks/cyl-group; more blocks just means more inodes.  So
> how does having rp07s make any difference?

Sorry, I wasn't explicit enough.  There is a hard limit (MAXIPG) on the number
of inodes per cylinder group; on rp07s, the default cylinder group is so
large that newfs (I believe) *silently* cuts back on the i-node density,
in order to stay within this limit.