All of lore.kernel.org
 help / color / mirror / Atom feed
From: Martin Wilck <mwilck@suse.com>
To: Xose Vazquez Perez <xose.vazquez@gmail.com>,
	device-mapper development <dm-devel@redhat.com>,
	Hannes Reinecke <hare@suse.de>
Subject: Re: least-pending multipath path selector WAS (9/14/14 !!!!): Re: Powerpath vs dm-multipath - two points of FUD?
Date: Mon, 01 Apr 2019 13:05:26 +0200	[thread overview]
Message-ID: <6df18d919a2ae5071b54e26107006169e7da10db.camel@suse.com> (raw)
In-Reply-To: <80c5be3f-f00a-36cb-c848-5207a8556b2f@gmail.com>

Hi Xose,

On Mon, 2019-04-01 at 01:16 +0200, Xose Vazquez Perez wrote:
> On 9/14/14 10:39 AM, Hannes Reinecke wrote:
> 
> > We do this with the switch to request-based multipathing.
> > Using one of the other load balancers (eg least-pending) and set
> > rr_min_io to '1' will give you exactly that behaviour.
> 
> As the original authors team, at HP, was dissolved ( 
> https://bugzilla.redhat.com/show_bug.cgi?id=438760#c14 )
> Hannes, do you consider least-pending mp selector helpful for
> upstream?
> 

I can't speak for Hannes, but I believe that the functionality provided
by this patch is mostly provided by the "queue-length" path selector
today. "service-time" has been the default since 2013, and most users
seem to be fine with that.

It's true that SLES kernels still support it, but I don't think it's
used much, if at all.

Even if the "least pending" selector was still needed, the patch would
need updating for current upstream, to accomodate the changes from
9659f811446a "dm mpath: push path selector locking down to path
selectors", and possibly other changes in the general dm/path selector
framework.

Martin

-- 
Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)


--
dm-devel mailing list
dm-devel@redhat.com
https://www.redhat.com/mailman/listinfo/dm-devel

      reply	other threads:[~2019-04-01 11:05 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-09 16:50 Powerpath vs dm-multipath - two points of FUD? Rob
2014-09-10 10:04 ` Bryn M. Reeves
2014-09-14  8:39 ` Hannes Reinecke
2019-03-31 23:16   ` least-pending multipath path selector WAS (9/14/14 !!!!): " Xose Vazquez Perez
2019-04-01 11:05     ` Martin Wilck [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=6df18d919a2ae5071b54e26107006169e7da10db.camel@suse.com \
    --to=mwilck@suse.com \
    --cc=dm-devel@redhat.com \
    --cc=hare@suse.de \
    --cc=xose.vazquez@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.