# problem with devices in /dev/mapper

## koslowj

Hello,

I used to have a working raid-1, but suddenly the divices, which used to be in /dev/mapper, have disappeared.  Moreover, I can't seem to reactivate them...

Here's the background: dmraid -r as well as dmraid -ay -v pdc... [-t][-v] works well, apparently, but doesn't create the devices as specified in fstab:

/dev/mapper/pdc_...1 /Raid/1        auto        noauto            0 0

+ 3 more such lines

This file hasn't been touched lately. So I created the directory /dev/mapper and the devices by means of

mknod /dev/mapper/pdc_...1 b 9 1

But when I attempt to mount /Raid/1 I get the message: "can't read superblock".  dmesg then yields a new line saying "FAT: unable to read boot sector".  Under Windows, the disks are readable as before.

I'm runing kernel 2.6.30-gentoo-r4, the problem did not occur under kernel 2.6.29-gentoo-r5.  Could the recent controversy over Microsoft's "patent" concerning long VFAT file names have something to do with my problem?  However, I can sill mount and read other VFAT-formatted disks.

-- Jürgen

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## koslowj

Unfortunately no help so far.  I've since tried dmraid-1.0.0.rc15 instead of the default dmraid-1.0.0.rc14.  At least this now reports that my raid set "was not activated", whereas the old version would poruce no indication of its failure.  Calling "dmraid -ay debug" produces the following output:

dmraid -ay --debug 

DEBUG: _find_set: searching pdc_cghgfdgdh

DEBUG: _find_set: not found pdc_cghgfdgdh

DEBUG: _find_set: searching pdc_cghgfdgdh

DEBUG: _find_set: not found pdc_cghgfdgdh

DEBUG: _find_set: searching pdc_cghgfdgdh

DEBUG: _find_set: found pdc_cghgfdgdh

DEBUG: _find_set: searching pdc_cghgfdgdh

DEBUG: _find_set: found pdc_cghgfdgdh

DEBUG: checking pdc device "/dev/sda"

DEBUG: checking pdc device "/dev/sdb"

DEBUG: set status of set "pdc_cghgfdgdh" to 16

DEBUG: checking pdc device "/dev/sda"

DEBUG: checking pdc device "/dev/sdb"

DEBUG: set status of set "pdc_cghgfdgdh" to 16

RAID set "pdc_cghgfdgdh" was not activated

DEBUG: freeing devices of RAID set "pdc_cghgfdgdh"

DEBUG: freeing device "pdc_cghgfdgdh", path "/dev/sda"

DEBUG: freeing device "pdc_cghgfdgdh", path "/dev/sdb"

As I mentioned before, this used to work until about the end of July, but even booting my previous kernel (2.6.29-r5) does not solve the problem.  Now I'm runing 2.6.30-r4.  

Googeling showed a number of such failures nut limited to Promise controllers.  Apparently, there are different versions of dmraid-1.0.0.rc15 available, I've seen references to -1, -5 and -6.

-- Juergen

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## koslowj

Reconfiguring the kernel by changing CONFIG_BLK_DEV_DM from a module to being hard-wired into the kernel seems to have solved the problem.  After rebooting, I now have a /dev/mapper directory (which previously was missing), and dmraid finds and activates the raid sets.  Not very reassuring, if something like this breaks out of the blue...

-- Juergen

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