Neil T. Dantam wrote:
> I'm having an issue (not quite a problem) creating LVM logical
> volumes. It seems that the way device files and symlinks are created
> has changed between Squeeze and Wheezy (or I have some bad
> configuration).
As far as I can tell these features have not changed between Squeeze
and Wheezy. They are the same on my machines.
> Old (working) Behavior
> ----------------------
> Performing an `lvcreate -L10G -nLVNAME VGNAME` would create:
>
> 1. New device file /dev/dm-N
> 2. Symlink /dev/mapper/VGNAME-LVNAME -> /dev/dm-N
> 3. Symlink /dev/VGNAME/LVNAME -> /dev/dm-N
>
> And everything was great.
Yes.
> New (broken) Behavior
> --------------------
> Performing an `lvcreate -L10G -nLVNAME VGNAME` creates:
>
> 1. New device file /dev/mapper/VGNAME-LVNAME
> (and apparently nothing else)
Uhm. No. It creates the others too.
> Then, lvcreate tries to open /dev/VGNAME-LVNAME, which fails because
> of no symlink with:
> /dev/VGNAME/LVNAME: not found: device not cleared
> Aborting. Failed to wipe start of new LV.
Works for me:
root@despair:~# lvcreate -L100M -ntest v1
Logical volume "test" created
root@despair:~# ls -l /dev/mapper/v1-test /dev/v1/test
lrwxrwxrwx 1 root root 8 Dec 10 22:59 /dev/mapper/v1-test -> ../dm-10
lrwxrwxrwx 1 root root 8 Dec 10 22:59 /dev/v1/test -> ../dm-10
This is with version 2.02.95-5 but Wheezy has 2.02.95-4 and the
changelog shows only local differences. I will say shouldn't matter
unless proven otherwise.
> Workarounds
> -----------
> Here are a few workarounds I've figured out:
>
> 1. Give lvcreate the '-Z n' flag. This does create a usable logical
> volume, but won't work with snapshots.
> 2. Manually create a symlink
> '/dev/VGNAME/LVNAME -> /dev/mapper/VGNAME-LVNAME'
> before running lvcreate
> 3. Give lvcreate the '--noudevsync' option. In this case, lvcreate
> makes a symlink for
> '/dev/VGNAME/LVNAME -> /dev/mapper/VGNAME-LVNAME'
> on its own (apparently).
What version of udev are you using? I could see this being a udev issue.
> Also, on a reboot of the machine, the device files end up in the
> original configuration, with both /dev/mapper/VGNAME-LVNAME and
> /dev/VGNAME/LVNAME as symlinks pointing to /dev/dm-N.
I did not understand what you said here. After a reboot everything is
okay? Or after a reboot you are then missing the symlinks that you
manually created? (The latter makes sense since /dev is dynamic.)
> While those workarounds are enough to get by, it would be nice to
> understand the underlying issue here. Can anyone shed some light on
> this?
Other than saying that your behavior is not the same as what I see.
Something seems to be wrong with your system.
Bob
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