

[dm-devel] Fdisk Multipath Disks on NetApp / IBM N series SAN with intention for Oracle 10G RAC OCR and Voting Disks



I am having a problem with a correct method for fdisk raw partitions in preparation for Oracle OCR. I know that you cant fdisk the /dev/mapper or /dev/dm-1 disks directly. Currently we have the following setup


mpath11 (360a98000433543364734454a6f533061)

[size=300 MB][features="1 queue_if_no_path"][hwhandler="0"]

\_ round-robin 0 [prio=8][active]


 \_ 4:0:0:1 sdl 8:176 [active][ready]

\_ round-robin 0 [prio=2][enabled]

 \_ 3:0:1:1 sdg 8:96  [active][ready]

 \_ 4:0:1:1 sdq 65:0  [active][ready]


I have fdisk’ed the sbd (underlying) disk and rebooted to bring multipath into sync.


/dev/mpath now has the following entries


lrwxrwxrwx   1 root root    7 Oct 25 11:53 mpath11 -> ../dm-0

lrwxrwxrwx   1 root root    7 Oct 25 11:53 mpath11p1 -> ../dm-9




brw-rw----   1 oracle oinstall 253,  4 Oct 25 11:53 mpath11

brw-rw----   1 oracle oinstall 253,  5 Oct 25 11:53 mpath11p1


I have tried addressing the


I have specified the raw devices /etc/sysconfig/rawdevices using the major minor id’s


/dev/raw/raw5 253 5


However when trying to exchange data between the shared luns


Dd if=/etc/hosts of=/dev/raw/raw5 I am getting an error.


However if I do the following dd if=/etc/hosts of=/dev/mpath/mpath11p1 the transfer works successfully.


This has come about as each of the servers is reporting the /mpath’s back as different numbers. The /dev/dm-1 etc are all fine, how do I bring the mpath back into sync, e.g. mpath1 across all boxes. Also am I going about things the right way or fundamentally flawed?




Charles Batchelor


Charles Batchelor

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