From: Joe Thornber <thornber@redhat.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] Snapshots and disk re-use
Date: Wed, 23 Feb 2011 13:09:33 +0000 [thread overview]
Message-ID: <1298466573.19562.147.camel@ubuntu> (raw)
In-Reply-To: <4D64FF3C.6080602@abpni.co.uk>
On Wed, 2011-02-23 at 12:36 +0000, Jonathan Tripathy wrote:
> Hi Everyone,
>
> We host many Xen VMs for customers. We use LVM as the fisk storage for
> these VMs. When a customer cancels, we generally dd their LV with
> /dev/zero, before removing the LV.
>
> If however we want to create a snapshot of a customer's LV, is there the
> chance that the data may appear on a new future LV if we were to create
> one (for a new customer)? Is is my understanding that most filesystems
> don't actually remove data from a disk when deleting a file, but just
> set an "ignore" tag of some sort...
I'm a bit confused about your scenario. But I think this will help:
The snapshot device is composed of 2 sub devices, the origin and the
exception store. Someone who only has visibility of the snapshot (ie.
your vm if your scenario is what I think it is) will have visibility of
all of the origin. So you _do_ need to worry about data leaks on the
origin device. Their view of the exception store is always a subset
which has been overwritten by origin data first. So data leaks are not
an issue for the exception store.
- Joe
next prev parent reply other threads:[~2011-02-23 13:09 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-23 12:36 [linux-lvm] Snapshots and disk re-use Jonathan Tripathy
2011-02-23 13:09 ` Joe Thornber [this message]
2011-02-23 13:57 ` Jonathan Tripathy
2011-02-23 14:16 ` Joe Thornber
2011-02-23 14:18 ` Jonathan Tripathy
2011-02-23 16:12 ` Ray Morris
2011-02-23 16:55 ` Jonathan Tripathy
2011-02-23 17:54 ` Stuart D. Gathman
2011-02-23 18:05 ` Jonathan Tripathy
2011-02-23 19:34 ` Stuart D. Gathman
2011-02-23 18:05 ` Stuart D. Gathman
2011-02-23 18:19 ` Jonathan Tripathy
2011-02-23 18:39 ` Les Mikesell
2011-02-23 19:39 ` Stuart D. Gathman
2011-02-23 20:03 ` Les Mikesell
2011-02-23 20:37 ` Stuart D. Gathman
2011-02-23 20:49 ` Jonathan Tripathy
2011-02-23 23:25 ` Stuart D. Gathman
2011-02-23 23:42 ` Stuart D. Gathman
2011-02-24 0:09 ` Jonathan Tripathy
2011-02-24 0:32 ` Stuart D. Gathman
2011-02-24 0:37 ` Jonathan Tripathy
2011-02-24 0:40 ` Jonathan Tripathy
2011-02-24 2:00 ` Stuart D. Gathman
2011-02-24 7:33 ` Jonathan Tripathy
2011-02-24 14:50 ` Stuart D. Gathman
2011-02-24 14:57 ` Jonathan Tripathy
2011-02-24 15:13 ` Stuart D. Gathman
2011-02-24 15:20 ` Jonathan Tripathy
2011-02-24 16:41 ` Jonathan Tripathy
2011-02-24 19:15 ` Nataraj
2011-02-24 19:25 ` Les Mikesell
2011-02-24 19:55 ` Stuart D. Gathman
2011-02-24 19:19 ` Stuart D. Gathman
2011-02-24 19:45 ` Stuart D. Gathman
2011-02-24 21:22 ` Jonathan Tripathy
2011-04-05 20:09 ` Jonathan Tripathy
2011-04-05 20:41 ` Stuart D. Gathman
2011-04-05 20:48 ` Jonathan Tripathy
2011-04-05 20:59 ` James Hawtin
2011-04-05 21:36 ` Jonathan Tripathy
2011-04-05 22:42 ` James Hawtin
2011-04-05 22:52 ` Jonathan Tripathy
2011-04-05 23:11 ` James Hawtin
2011-04-05 23:19 ` Jonathan Tripathy
2011-04-05 23:39 ` James Hawtin
2011-04-06 0:00 ` Jonathan Tripathy
2011-04-06 0:08 ` Stuart D. Gathman
2011-04-06 0:14 ` Jonathan Tripathy
2011-04-06 0:16 ` James Hawtin
2011-04-06 0:28 ` Jonathan Tripathy
2011-04-06 0:38 ` Stuart D. Gathman
2011-04-06 0:43 ` Stuart D. Gathman
2011-04-06 1:36 ` James Hawtin
2011-04-06 1:47 ` Jonathan Tripathy
2011-04-06 1:53 ` James Hawtin
2011-04-06 0:47 ` Jonathan Tripathy
2011-04-06 0:42 ` James Hawtin
2011-04-06 0:50 ` Jonathan Tripathy
2011-04-06 1:20 ` James Hawtin
2011-04-06 1:45 ` Jonathan Tripathy
2011-02-23 19:49 ` Nataraj
2011-02-23 19:24 ` Stuart D. Gathman
2011-02-23 19:07 ` [linux-lvm] Problem executing lvm related commands Tinni
2011-02-23 19:33 ` [linux-lvm] Snapshots and disk re-use Phillip Susi
2011-02-23 19:45 ` Stuart D. Gathman
2011-02-23 19:56 ` Nataraj
2011-02-23 13:18 ` Sunil_Gupta2
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