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From: "Gayn Winters" <gayn.winters@bristolsystems.com>
To: "'Ted Mittelstaedt'" <tedm@toybox.placo.com>,
	"'Steve Bertrand'" <iaccounts@ibctech.ca>, <freebsd-questions@freebsd.org>
Date: Sat, 5 Nov 2005 14:40:29 -0800
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Subject: RE: gmirror on 1 or 2 IDE cables
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> -----Original Message-----
> From: Ted Mittelstaedt [mailto:tedm@toybox.placo.com] 
> Sent: Friday, November 04, 2005 1:26 PM
> To: Steve Bertrand; gayn.winters@bristolsystems.com; 
> freebsd-questions@freebsd.org
> Subject: RE: gmirror on 1 or 2 IDE cables
> 
> 
> >-----Original Message-----
> >From: owner-freebsd-questions@freebsd.org 
> >[mailto:owner-freebsd-questions@freebsd.org]On Behalf Of 
> Steve Bertrand
> >Sent: Thursday, November 03, 2005 7:28 AM
> >To: gayn.winters@bristolsystems.com; freebsd-questions@freebsd.org
> >Subject: RE: gmirror on 1 or 2 IDE cables
> >
> >
> >
> >> Using gmirror to mirror two identical drives, how much of a 
> >> performance hit is it to have
> >> 
> >> 1.  Both drives on one IDE cable?
> >> Compared to:
> >> 2.  One drive primary on one cable and one secondary on the 
> >> other cable?
> >> Compared to:
> >> 3.  Both drives primary but on separate IDE cables?
> >
> >My understanding that only a single drive on each IDE channel can be
> >accessed at any one time.
> >
> 
> Which may or may not matter depending on what he's doing.  Are we
> talking mainly reads or writes here?
> 
> Ted
> 
I was mostly thinking about writes; however, now that you raise the
issue, can gmirror interleave reads from the two mirrored disks?

-gayn