Date: Fri, 18 Jul 2003 12:23:36 +0930 From: Malcolm Kay <malcolm.kay@internode.on.net> To: "Mike Maltese" <mike@pcmedx.com>, <freebsd-questions@freebsd.org> Subject: Re: vinum and newfs Message-ID: <200307181223.36296.malcolm.kay@internode.on.net> In-Reply-To: <003f01c34cc7$5e67a700$f4f0a8c0@pcmedx.com> References: <003f01c34cc7$5e67a700$f4f0a8c0@pcmedx.com>
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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 bett= er > results in just about every instance by passing -b 16384 -f 2048 to new= fs. > This doesn't make sense to me as those are the defaults for newfs if th= ey > are not specified, but looking at the disklabel after a newfs, it shows > 8192/1024. Should these options really make a performance difference, a= nd > if so, how? > > Thanks, Mike I have had similar experience, getting 8192/1024 when using newfs on a vi= num=20 volume. Obviously 16384/2048 is not the default in this case, in spite of= the=20 newfs man pages.=20 In a classical file system I believe these numbers are taken from the=20 disklabel and it is realy the disklabel that supplies these defaults for = the=20 partitions. For vinum the individual volumes do not have a corresponding=20 disklabel partition. -- All guess work so don't take it too seriously. Malcolm
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