RE: [linux-lvm] read-only media in a LVM?

["Sean P. Kane" <spkane genomatica com>]

Title: Message

I saw this email below and was wondering if this is supported in both dm and the LVM2 tools now. I am trying to setup a bootable cd, that can be written to during that session and this would be a god send, since as the last person points out there really isn't a mature way to do this in the 2.4/2.5 kernels. 2.6 is suppose to have a unionfs sometime after release, but this is an immediate project.

 

Thanks,

Sean

 

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Sean P. Kane                                               spkane genomatica com
Lead Infrastructure Architect                                      Genomatica, Inc.
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"When we destroy something man has created we call it vandalism......
 When we destroy something that Gaia has created we call it progress."

 

[linux-lvm] read-only media in a LVM?

Joe Thornber linux-lvm sistina com
Tue May 28 03:44:01 2002

 

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On Mon, May 27, 2002 at 04:37:49PM -0700, Ami Fischman wrote:

> Hi there,

> I am wondering whether it is possible to have a read-only fs (CDROM, image,

> etc) as part of an LVM-managed volume. I see references to COW

> (copy-on-write, I'm hoping :)) in the kernel drivers/md/ files, but it's not

> at all clear to me whether or not the current drivers can be used to

> implement a "translucent" or "inheriting" file system (one where a base fs

> is given, on r-o media, and changes to it get recorded on another device,

> presumabely a r-w fs). Please let me know whether this is currently

> possible, being planned for the future, or if I'm making no sense above &

> you want me to clarify :). For a not-quite-mature example of what I'm

> talking about, see translucency.sf.net.

 

In fact you can do this now if you use just device-mapper/dmsetup :)

It's just the LVM2 tools that don't support it yet.- Joe