problem with devices in /dev/mapper

koslowj · Tux's lil' helper Joined: 15 Feb 2005 Posts: 100

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

koslowj · Tux's lil' helper Joined: 15 Feb 2005 Posts: 100

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

koslowj · Tux's lil' helper Joined: 15 Feb 2005 Posts: 100

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