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Re: su,sw suboptions clarification on fs creation



On Thu, 2003-01-30 at 17:05, Joshua Baker-LePain wrote:
> On 30 Jan 2003 at 4:12pm, Dragos Delcea wrote
> 
> > given a recent linux distribution (SuSE 8.1) and a raid 0 logical disk
> > (hardware raid with stripe=16k) with 3 scsi disks, what are the right
> > parameters used at fs creation?
> > I used:
> > 
> > #mkfs.xfs -l logdev=/dev/sda3,size=32768b -d \
> > su=16384,sw=49152,unwritten=0 /dev/sdb1 -f;
> > 
> > but I have doubts about sw suboption, in the man page of mkfs.xfs the
> > explanation seemd clear at first, but (I'm not an native english
> > speaker) the more I stare at it, the more confused I get. Should it be
> > sw=(su*number_of_disks)=49152, or sw=number_of_disks=3?
> 
> Given my reading of the man page, I think you are correct that sw should 
> be 3.
You are right; I wasn't paying attention.
At fs creation, it told me:
...
	sunit=4      swidth=12 blks, unwritten=0
...
which answers my question.
I'll do some (write intensive) tests to see if it behaves better than
ext2..

cheers,
dragos
> 
> Your other option is to use sunit and swidth switches, which are 
> alternatives to su and sw.  These are specified in 512-byte units, and for 
> your setup would be sunit=32768,swidth=98304.
> 
> -- 
> Joshua Baker-LePain
> Department of Biomedical Engineering
> Duke University
> 
> 
>