I am having trouble trying to install version 2.6.15 of the linux kernel onto a machine that is currently running 2.6.9 version of the kernel. I am using the 2.6.9 configuration file and running make install successfully. When I try to boot the new kernel, I get
the following:
No entry for device mapper found Is device mapper driver missing from kernel?
Failure to communicate with kernel
mount: error 19 mounting ext3
mount: error 2 mounting none

Apparently the device mapper is being used on the current kernel and does exist in the direcotory /sys/misc. What do I need to do to get my new kernel to recognize it? According to what I've read, every kernel since 2.6.9 should have it in the source.
I checked the .config file and couldn't find anything called device
mapper. There was an entry for an IOMAPPER associated with a certain
scsi device that was commented out, but I have no idea what to put
after =. I couldn't find a comparable entry using make menuconfig. Any help would be greatly appreciated.

Mike

Probably the reason you couldn't find it is that it's a sub-entry (requires a specific parent to be enabled before it becomes chooseable).

The setting you're looking for is:

Device Drivers=> Multi-device support (RAID and LVM) (this must be selected)=> Device mapper support.

If you choose to make device mapper support a module rather than statically compiled ("M" instead of "*", don't forget to make sure that the module (dm-mod) is loading properly during the course of boot.

Hope this helps.

How do you make sure that the dm-mod is loading properly during the boot? I tried recompiling everything use make oldconfig. Device mapper is enabled as M, but I still get the same error message.

Mike