On Sat, Mar 23, 2002 at 04:06:06AM +0100, Hubert Feyrer wrote:
> In article <NFBBJGHFKLGPMPFNJNAIGENNCNAA.brucem@cat.co.za> you wrote:
> > I can write this label fine, and a 'newfs /dev/rwd1f' works. However, when I
> > do a 'newfs /dev/rwd1g' I get:
> >   With 17867 cylinder groups 35 cylinder group summary area are needed.
> >   Only 31 are available, reduce the number of cylinder groups
> > 
> > Do you know why this doesn't work?
> 
> Funny, I had something similar from on a Solaris box the other day (with
> ah 280GB RAID).

Because an array of summary information for each 'cylinder' group
is kept in the superblock.  This gives an upper limit to the
number of cylinder groups a disk can have.
(looks like 31 * 512 = 15872 for the default block/sector size)

You need to increase the size of each cylinder group when you call newfs.

The defaults aren't right for modern disks.  IIRC someone recently
suggested that about 100-200 cylinder groups is reasonable.  Searching
through 17867 of them for free space (when the disk gets full) cannot
be advantageous.

There is also limit on the number of blocks per cylinder group...

	David

-- 
David Laight: david@l8s.co.uk