vinum and newfs

[Malcolm Kay]

On Fri, 18 Jul 2003 10:26, Mike Maltese wrote:
> What impact do disk block and fragment sizes have on a vinum volume?  I've
> been benchmarking an array of three drives in striped and raid5
> configurations with various stripe sizes.  I've noticed that I get better
> results in just about every instance by passing -b 16384 -f 2048 to newfs.
> This doesn't make sense to me as those are the defaults for newfs if they
> are not specified, but looking at the disklabel after a newfs, it shows
> 8192/1024. Should these options really make a performance difference, and
> if so, how?
>
> Thanks, Mike

I have had similar experience, getting 8192/1024 when using newfs on a vinum 
volume. Obviously 16384/2048 is not the default in this case, in spite of the 
newfs man pages. 

In a classical file system I believe these numbers are taken from the 
disklabel and it is realy the disklabel that supplies these defaults for the 
partitions. For vinum the individual volumes do not have a corresponding 
disklabel partition. -- All guess work so don't take it too seriously.

Malcolm