Subject: Re: LFS partition limitations
To: None <>
From: Thor Lancelot Simon <>
List: current-users
Date: 10/03/2000 17:49:14
On Tue, Oct 03, 2000 at 04:34:31PM -0500, Tracy J. Di Marco White wrote:
> Ok, my husband agreed to FFS+softdep.  Should I should send-pr this:
> lyra:~# newfs /dev/rraid0a
> With 160016 cylinder groups 312 cylinder group sumary area are needed.
> Only 31 are available, reduce the number of cylinder groups.
> Or is this just something I need to deal with using newfs's options
> or with disklabel?  I'm a little wary of manipulating the disklabel
> that was created when I configured the raid.

With a filesystem this large, minimizing FFS's totally unreasonable number
of cylinder groups is a priority. You probably want to:

1) Increase the filesytem block/fragment size to 16K/2K or even 32K/4K.
   Unless you intend to fill all that space with tiny, tiny files, it
   won't matter; it'll just increase performance.

2) Use newfs's '-c' option to explicitly set the number of cylinder groups
   as large as you can.  For any given block size, there will be a maximum
   number of blocks in a cylinder group; start with something silly like
   "-c 65536" and work downwards.  A larger block size will get you more

Even without changing the blocksize from 8K, you can do a lot better than
newfs's defaults, which are reasonable only for tiny, ancient disks, if

Thor Lancelot Simon	                            
	the effort to perceive simply the cruel radiance of what is