linux-scsi.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Chandra Seetharaman <sekharan@linux.vnet.ibm.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: device-mapper development <dm-devel@redhat.com>,
	linux-scsi@vger.kernel.org, michaelc@cs.wisc.edu,
	Benoit_Arthur@emc.com, Eddie.Williams@steeleye.com
Subject: Re: [dm-devel] [PATCH 0/4] scsi_dh: Make scsi_dh_activate asynchronous
Date: Thu, 22 Oct 2009 09:06:28 -0700	[thread overview]
Message-ID: <1256227588.6475.6.camel@chandra-ubuntu> (raw)
In-Reply-To: <20091022010608.GA10445@infradead.org>

Hi Christoph,

Thanks for looking into this.

Babu (LSI) and I did some testing and found couple of problems. Major
one was that moving all luns blindly causes luns to be moved to their
non-preferred path against the user's setting, which is a no-no.

Here is the email Babu sent on this:
http://marc.info/?l=linux-scsi&m=125495712310371&w=2

chandra

On Wed, 2009-10-21 at 21:06 -0400, Christoph Hellwig wrote:
> On Wed, Oct 21, 2009 at 09:22:40AM -0700, Chandra Seetharaman wrote:
> > Hello All,
> > 
> > Currently, device handlers process path activation in series. This leads
> > to a lot of time delay when more than 100 luns are involved. For example,
> > with lsi rdac 100+ luns take about 12-15 minutes. This was found by Moger
> > Babu of LSI.
> 
> So what happened to the suggestion to just switch over per target
> instead of per lun?   It's the obviously much better way to do, and
> unless there are bugs in the hardware preventing it from working it
> should be the way to go.
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html


      reply	other threads:[~2009-10-22 16:06 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-21 16:22 [PATCH 0/4] scsi_dh: Make scsi_dh_activate asynchronous Chandra Seetharaman
2009-10-21 16:22 ` [PATCH 1/4] scsi_dh: Change the scsidh_activate interface to be asynchronous Chandra Seetharaman
2009-10-22 23:26   ` Moger, Babu
2009-10-22 23:29   ` Moger, Babu
2009-10-21 16:22 ` [PATCH 2/4] scsi_dh: Make rdac hardware handler's activate() async Chandra Seetharaman
2009-10-22 23:30   ` Moger, Babu
2009-10-21 16:22 ` [PATCH 3/4] scsi_dh: Make hp " Chandra Seetharaman
2009-10-21 16:23 ` [PATCH 4/4] scsi_dh: Make alua " Chandra Seetharaman
2009-10-22  1:06 ` [dm-devel] [PATCH 0/4] scsi_dh: Make scsi_dh_activate asynchronous Christoph Hellwig
2009-10-22 16:06   ` Chandra Seetharaman [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=1256227588.6475.6.camel@chandra-ubuntu \
    --to=sekharan@linux.vnet.ibm.com \
    --cc=Benoit_Arthur@emc.com \
    --cc=Eddie.Williams@steeleye.com \
    --cc=dm-devel@redhat.com \
    --cc=hch@infradead.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=michaelc@cs.wisc.edu \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).