# SOLVED - dmraid and LVM2 Questions and maybe suggestions

## net-0

I have a question I wanted to post before I go to sleep tonight.... maybe someone has a quick response.

If not I will continue on this project tomorrow =)

This is the material that I have been using to make this little project.

http://gentoo-wiki.com/Installing_on_LVM2_And_Raid5#device.map

and 

http://gentoo-wiki.com/HOWTO_Install_Gentoo_on_an_LVM2_root_partition

I have got most of what I wanted working.... except this problem.....

I can't mount my lvm partitions.... when I lvdisplay it says this,

```
fileserver ~ # lvdisplay

  /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.

  --- Logical volume ---

  LV Name                /dev/vg/usr

  VG Name                vg

  LV UUID                j5AWJY-3TuC-BPxN-bVqK-OePB-b9MZ-EY6pAV

  LV Write Access        read/write

  LV Status              NOT available

  LV Size                10.00 GB

  Current LE             2560

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

  --- Logical volume ---

  LV Name                /dev/vg/home

  VG Name                vg

  LV UUID                kjte2c-MfkR-jKAZ-0PGE-zAgo-Iwcx-1s2eFn

  LV Write Access        read/write

  LV Status              NOT available

  LV Size                800.00 GB

  Current LE             204800

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

  --- Logical volume ---

  LV Name                /dev/vg/opt

  VG Name                vg

  LV UUID                SH1LIC-GORn-wMJg-XegP-Fs77-uwu3-yd2bIQ

  LV Write Access        read/write

  LV Status              NOT available

  LV Size                5.00 GB

  Current LE             1280

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

  --- Logical volume ---

  LV Name                /dev/vg/var

  VG Name                vg

  LV UUID                zNcztI-lgRE-vO2J-Bm0c-L1gw-nqo8-yGoe0e

  LV Write Access        read/write

  LV Status              NOT available

  LV Size                10.00 GB

  Current LE             2560

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

  --- Logical volume ---

  LV Name                /dev/vg/tmp

  VG Name                vg

  LV UUID                X2E3fi-nbe3-1jfO-zkIf-g7hs-Vv1k-dALp1U

  LV Write Access        read/write

  LV Status              NOT available

  LV Size                2.00 GB

  Current LE             512

  Segments               1

  Allocation             inherit

  Read ahead sectors     0

```

I have this setup like this,

/boot is raid1 across sda1 sdb1 sdc1 sdd1

/swap is raid1 across sda2 sdb2 sdc2 sdd2

/ is raid5 across sda3 sdb3 sdc3 sdd3

/lvm partitions is sda4 sdb4 sdc4 sdd4

and I have no understanding of this yet.... its a work in progress... I'm just looking for clues to start... maybe someone with knowledge of lvm can recommend some reading so I can get better incite into this.

I'm going to try messing with device mapper and dmraid in the kernel tomorrow... just hopping someone can save me some trouble of doing things randomly just to figure them out instead of the right way!

Also if someone does respond can you maybe post an example of how to add more space to an lvm partition? 

Or maybe give me some ideas about how to make a fileserver safe and what not.... It's a personal home fileserver... but I'm curious what a production environment would have in place for storing important information. Just little things like NFS I want that setup also... rsync server for local syncing... just post up fun projects and I will be greatly appreciative.

Thanks,

--neto   :Shocked: 

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## net-0

And here is some more information regarding this problem I am having =)

```
fileserver ~ # vgchange -a y

  /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.

  0 logical volume(s) in volume group "vg" now active

```

Not sure what I'm doing wrong.  :Shocked: 

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## net-0

bump?

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## Muddy

Same problem!!!!

Only...

My system has been up and running for 2 years now and working peachy until the past few weeks I have been having odd lock up problems so I thought I have tracked it down to something in xfce so I did a emerge -uvDN (and other options) for xvcf4 and other packages associated.. 

during the emerge X locked up again (yet the text in term kept scrolling by) so once it finished I ssh'd in and killed X restarted X and all seemed ok (and I DID NOT run etc-update, duh!) so I rebooted and now I'm getting the exact same error you are.

when I log in maint mode and try vgscan it finds the volume group fine but 

vgscan --mknodes results in the same errors complaining about /dev/mapper/control: stat failed: too many levels of symbolic links etc..

the initial problem on boot is 

```

*Setting up the Logical Volume Manager ...

 /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.

```

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## net-0

Hey Muddy did you ever find a solution to this?  :Shocked: 

--neto

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## Muddy

yes, popped in the install cd and mounted my raid 1 drives and enabled the volume groups then mounted them then chrooted in, checked the emerge log and  found that I emerged device-mapper but not lvm2, so I re-emerged that and it would not even load, so I pulled it all back together with the install cd chrooted back in and upgraded to 2.6.22-r9 kernel and now it's working great again

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## net-0

solved my problem =)

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## Muddy

also make sure to run etc-update, I found over 130 config files I had to review =(  that took some time

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