From: Zdenek Kabelac <zkabelac@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>,
Shawn Guo <shawn.gsc@gmail.com>,
David Teigland <teigland@redhat.com>
Subject: Re: [linux-lvm] A couple of questions on locking library
Date: Fri, 31 May 2019 10:38:18 +0200 [thread overview]
Message-ID: <3ebc32f0-963e-9d18-baf7-03a762ec12f5@redhat.com> (raw)
In-Reply-To: <CAJBJ56LoBQF_cqfXwKdHVqhJfRHioBN9BJCy_fiqDRW36pCPuA@mail.gmail.com>
Dne 31. 05. 19 v 9:13 Shawn Guo napsal(a):
> Hi David, Zdenek,
>
> Comparing to stable-2.02 branch, I noticed that there are significant
> changes around locking infrastructure on master branch. I have a
> couple of questions regarding to these changes.
>
> 1. I see External Locking support was removed as part of clvmd
> removal. What's the reason for dropping External Locking support? I'm
> asking because we are investigating the possibility to use hardware
> assisted locking for cluster, in form of External Locking extension.
>
> 2. It seems there have never been real support for LV (Logic Volume)
> locking. On stable-2.02 branch, the LV locking interface is used as
> activation path instead of real locking on LV. And on master branch,
> activation path gets separated off from locking infrastructure. As
> the result, the LV interface is dropped completely from locking
> infrastructure. My question is why there have never been LV locking
> support. Is the LV locking support an invalid requirement at all? Or
> it's just because no one cares about it enough to add the support?
>
> Thanks for your time, and appreciate any comment you would give here.
With stable-2.02 branch - there was always per-LV locking.
The 'state' of the LV was matching state of lock.
http://people.redhat.com/agk/talks/CLVM-UKUUG2007/
See the 'DLM – Distributed Lock Manager'
The lock however was always took only for top-level LV - never for those
component LVs.
--
There is however believe, that users no longer use volumes with shared
activation (active at one time on multiple hosts) - so lvm2 is now being moved
transformed to theoretically less complex locking scheme...
Regards
Zdenek
next prev parent reply other threads:[~2019-05-31 8:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-31 7:13 [linux-lvm] A couple of questions on locking library Shawn Guo
2019-05-31 8:38 ` Zdenek Kabelac [this message]
2019-05-31 14:47 ` Shawn Guo
2019-06-03 14:08 ` David Teigland
2019-05-31 14:38 ` David Teigland
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=3ebc32f0-963e-9d18-baf7-03a762ec12f5@redhat.com \
--to=zkabelac@redhat.com \
--cc=linux-lvm@redhat.com \
--cc=shawn.gsc@gmail.com \
--cc=teigland@redhat.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 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).