Bug#316883: lvm2: creates device nodes as root:root 600, breaking amanda

[Marc Haber]

On Tue, Jul 05, 2005 at 09:53:42AM +0200, Bastian Blank wrote:
> On Mon, Jul 04, 2005 at 04:55:11PM +0200, Marc Haber wrote:
> > unlike lvm10 (which created LV device nodes as root:disk 660), lvm2
> > creates its device nodes as root:root 600:
> 
> lvm2 creates no devices, this is done by libdevmapper.

So this is actually a libdevmapper wishlist item?

> > brw-------   1 root root 253,  1 Jul  4 11:32 vg0-usr
> > This precludes amanda backups from happening.
> 
> Write access to disks is nearly as good as root.

This is how non-LVM systems do it, and we usually follow the principle
of least surprise.

> Get the CAP_DAC_READ
> capability, which is designed for backup purposes.

How can an Amanda process obtain that capability? Does it work on a
2.4 kernel as well?

> > Please deliver lvm2 in a way that makes the LV device nodes readable
> > by group disk. If this can be done, please tell me how to change my
> > local configuration to make backup possible again.
> 
> Use udev if you need special modes.

Is udev available on a kernel 2.4 system? Having different kinds of
LVM userspace depending on kernel version in use is bad enough, but
having 2.4 and 2.6 systems deviate from each other _that_ badly is
especially bad for a critical application like backup.

Greetings
Marc

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