[dm-devel] how to do failover using device mapper

[Sunil Joshi]

Hi Experts,
I am trying to find a way to path failover  using device mapper.
I have configured /etc/multipath.conf and other instructions as given
in http://kbase.redhat.com/faq/FAQ_51_7170.shtm.

I can see multipath -ll output which shows two entries corresponding
to two path connected to system.
e.g
\_ round-robin 0 [enabled]
 \_ 4:0:0:0 sdc 8:32  [active][ready]
 \_ 3:0:0:0 sdg 8:96  [active][ready]


ls -l /dev/dm-* shows
brw-r-----  1 root root 253, 0 Feb 23 03:11 /dev/dm-0
brw-r-----  1 root root 253, 1 Feb 23 03:11 /dev/dm-1


I have 7 partitions on /dev/sdc and want to mount a particular device
/dev/sdc7.  How should I do it. I want to mount the sdc7 , then in
between of I/O activity I will close the port so that I/O will direct
to other port.

I dont want to use mdadm  , so any other way to create group of device ?

I have many more questions , like
1) What /dev/dm-# indicates.
2) What kpartx does

I searched the mail archive but not able to find suitable.

Thanks for your time.

Regards
sjoshi