Date: Thu, 10 May 2012 08:13:29 -0700 From: Trent Nelson <trent@snakebite.org> To: "mj@feral.com" <mj@feral.com> Cc: "freebsd-geom@freebsd.org" <freebsd-geom@freebsd.org> Subject: Teaching gmultipath about path cost/priority Message-ID: <4A6AB54F-A0B3-40A6-A8E4-EE9992B5C52D@snakebite.org>
next in thread | raw e-mail | index | archive | help
Hi again Matt,
I'm sure I'll eventually find a subsystem relevant to me that you *didn't*
author, but for now, I have some gmultipath questions.
Basically, the entire approach is perfect for me. As all my SAN targets
are JBODs (i.e. I don't have any targets that could saturate a single HBA
and thus would benefit from active/active multipathing), active/passive
is exactly what I want.
But... in my case, all paths are not equal. My fabric has four switches
and is fully meshed; a host may have up to four HBAs, each one connected
to a separate switch. From a redundancy and failover perspective, I've
made sure there are an abundance of paths available to a single disk.
However, unless something has failed, there's only one path I want to use,
as I've pre-planned that path to be the most optimal.
It sounds like the order gmultipath uses to select paths is derived from
the order it tastes disks -- something I have very little control over.
It'd be ideal if there was a way of teaching gmultipath about a path
cost/priority, so that it can make an informed decision about which
path to choose a) when first initializing, and b) during failover.
Thoughts?
Regards,
Trent.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4A6AB54F-A0B3-40A6-A8E4-EE9992B5C52D>