# [device mapper] LVM failure due to device-mapper

## paper83

Hello,

I'm trying to set up basic lvm array with 2 drives. Both are 250gb (WD & Seagate).

My drives are /dev/sda3 & /dev/sdb1. 

when I try to execute command 'lvcreate' I get: 

```
  /dev/mapper/control: stat failed: Too many levels of symbolic links

  /dev/mapper/control: mknod failed: File exists

  Failure to communicate with kernel device-mapper driver.

  striped: Required device-mapper target(s) not detected in your kernel

  lvcreate: Create a logical volume
```

Driver for device-mapper is ofcourse loaded into kernel. I also tried it as module, load it; result was the same.

```
device-mapper: uevent: version 1.0.3

device-mapper: ioctl: 4.12.0-ioctl (2007-10-02) initialised: dm-devel@redhat.com

device-mapper: multipath: version 1.0.5 loaded

device-mapper: multipath round-robin: version 1.0.0 loaded

device-mapper: multipath emc: version 0.0.3 loaded

device-mapper: multipath hp-sw: version 1.0.0 loaded

device-mapper: multipath rdac: rdac: version 0.4 loaded
```

I noticed one strange thing though, /dev/mapper/control is linked to itself and link seems to be broken (blinking).

```
Raven / # ll /dev/mapper/control

lrwxrwxrwx 1 root root 7 Mar 26  2008 /dev/mapper/control -> control
```

On my other box where things are working as intended, /dev/mapper/control is linked to /dev/device-mapper.

On this box with problems /dev/device-mapper does not exist.

I've got latest packages from stable arch, running on 2.6.24-gentoo-r3:

[ebuild   R   ] sys-fs/udev-115-r1

[ebuild   R   ] sys-fs/device-mapper-1.02.22-r5

Any help is greatly appreciated,

-Matija

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## BradN

Hmm, double check the kernel config... failing that, try an older kernel version... I can't believe they would have messed something up that breaks device mapper that badly though.  Maybe enable some extra raid options and things like that just to make sure the support gets built.

Another idea, use mknod to create the missing device and re-link the other one (copy the major/minor numbers from your working machine)

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## paper83

I tried with older kernels aswell, no luck.

After friend suggested me to rebuild udev and revdep-rebuild, mapper started working. Actually does make sense  :Wink: 

Problem solved.

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