Red Hat Bugzilla – Bug 390911
RFE - sfdisk does not work with /dev/mapper multipath'ed devices
Last modified: 2010-10-22 16:32:57 EDT
Description of problem:
sfdisk does not work with /dev/mapper multipath'ed devices
This command does not work:
#sfdisk --no-reread /dev/mapper/oraRAC4ART4_disk1_4500M <
Disk oraRAC4ART4_disk1_4500M: cannot get geometry
sfdisk: bad input
Now... from the output of multipath -ls:
_ round-robin 0 [active]
_ 1:0:0:20 sdaq 66:160 [active][ready]
_ 0:0:0:20 sdn 8:208 [active][ready]
Notice /dev/sdn is one of the paths. It works:
#sfdisk --no-reread /dev/sdn < /root/4500M-partitioning.txt
Successfully wrote the new partition table
Re-reading the partition table ...
Version-Release number of selected component (if applicable):
Steps to Reproduce:
Successfully perform sfdisk operations against multi-pathed devices.
SEG comments on this request:
this is a feature, and one I highly doubt will go anywhere but here it goes.
Device-mapper devices may describe anything, and may not necessarily have a
one-to-one relationship with its underlying device (which is the case with LVM).
Multipath happens to be 1 of the many things that utilizes DM, and is the only
thing that has a one-to-one relationship with the underlying device. So
although it may make sense to use fdisk/sfdisk with dm devices in this
particular case, there is an overwhelming number of cases where you don't want
this functionality, you would even want to prohibit it. I explained this to
Cisco when I was onsite with them.
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.