linux-lvm.redhat.com archive mirror
 help / color / mirror / Atom feed
From: Alasdair G Kergon <agk@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] Standard Linux Framework for Snapshot Notification
Date: Fri, 18 Nov 2005 21:56:48 +0000	[thread overview]
Message-ID: <20051118215648.GW26394@agk.surrey.redhat.com> (raw)
In-Reply-To: <64c763540511140550t4de2bbc8scdc58e4d38717a15@mail.gmail.com>

On Mon, Nov 14, 2005 at 07:20:59PM +0530, Block Device wrote:
>   I  want to know whether Linux provides any standard interface for
> volume managers etc so that applications can register themselves to be
> notified when a snapshot needs to be taken.

Not yet, but it's a reasonable thing to ask for.

> If there isnt any such interface how is consistency guaranteed for
> application data when a snapshot is taken ? eg. How does one take
> (consistent) snapshots of database instances w/o  first quiescing them
> ?
 
At the moment you have to do things the other way around:
  quiesce database
  lvcreate -s
  wake database

There already exists an in-kernel filesystem hook so that mounted filesystems 
get the notifications automatically so they can sync their metadata, and
the block devices get flushed.

Alasdair
-- 
agk@redhat.com

  reply	other threads:[~2005-11-18 21:56 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-14 13:50 [linux-lvm] Standard Linux Framework for Snapshot Notification Block Device
2005-11-18 21:56 ` Alasdair G Kergon [this message]
2005-11-23  6:29   ` Block Device

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=20051118215648.GW26394@agk.surrey.redhat.com \
    --to=agk@redhat.com \
    --cc=linux-lvm@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).