On 4/5/07, Shlomo Solomon <[EMAIL PROTECTED]> wrote:
QUESTION #1 - I don't know if it was neccessary to comment them all, but the link Noam pointed to mentioned dm-mirrror and dm-mod so I commented all lines including either of them. Was that the right thing to do?
I don't think it is necessary. Though, one needs to understand how the mandriva "control panel" works behind the scenes and where it is configured to use device-mapper and why. QUESTION #2 - I booted twice (before and after making the above change) and
compared dmesg. I found that before making the change, there were many lines of device-mapper errors and these were gone after making the change. So what were these error messages? device-mapper: 4.6.0-ioctl (2006-02-17) initialised: [EMAIL PROTECTED] device-mapper: dm-linear: Device lookup failed device-mapper: error adding target to table device-mapper: dm-linear: Device lookup failed device-mapper: error adding target to table << lines repeated about 50 times >> device-mapper: dm-linear: Device lookup failed device-mapper: error adding target to table device-mapper: dm-linear: Device lookup failed device-mapper: error adding target to table
In respect of which physical device does this error occurred? Can you tell?
QUESTION #3 - While GOOGLing for this, I found some mentions of EVMS. I seem to remember that on a previous version of Mandriva I had disk-access problems until I un-installed EVMS. But now, I see that it's installed on my system. Do I need it and if so, why?
AFAIK, EVMS stands for Enterprise Volume Management System. It is some opensource project targeted at providing the sysadmin a consolidated way to manage all the storage devices he has no matter what technology is used to administer them. (LVM / MD / etc.) I played around with this tool once, and as far as I recall, it takes advantage of device-mapper in the process, though I can't remember how. QUESTION #4 - I still don't know the answers to the questions I asked in my
previous post. >[EMAIL PROTECTED] solomon]# dmsetup deps >sdc8: 1 dependencies : (8, 32) >sdc14: 1 dependencies : (8, 32) >sdc7: 1 dependencies : (8, 32) >sdc13: 1 dependencies : (8, 32) >sdc6: 1 dependencies : (8, 32) >sdc12: 1 dependencies : (8, 32) >sdc5: 1 dependencies : (8, 32) >sdc11: 1 dependencies : (8, 32) >sdc10: 1 dependencies : (8, 32) >sdc9: 1 dependencies : (8, 32) > > >OK - I can't say I really understand what this means. For instance: >- what are these "dependencies"?
If I did my math correctly then: 8 - This is the major number of the SCSI kernel driver. 32 - Is the minor number pointing on /dev/sdc 'ls -l /dev/sdc' should show you these numbers.
- how did they get created?
Well. Ask Mandriva :) But it proves that you have devices managed by device-mapper.
- why only for sdc (not sda or sdb)?
same answer here. In the bottom line, disabling device-mapper in some kernel hack did the trick. Just be aware that if you run 'depmod -a' it will not sustain. (Same goes for a kernel upgrade). Best way is to understand where it is configured that your sdc devices should be managed by device-mapper. (recursive grep on /etc is a good start). Device mapper gives you the flexibility to manage your devices in an easier way. It is modular and robust (bla bla). It can be used to encrypt your devices, have LVM over them, and many other neat features. Anyhow, I don't think that any of this "robust" features are speaking to you, because you chose to partition all your disks into very small parts in a very "hardcoded" way. - Noam
