disk partitions
For each device (sda to sdu) enter:
$ fdisk /dev/sda
Command (m for help): u
Command (m for help): p
Command (m for help): n
Command (m for help): p
1
32768
Â
 w
(Where ?? are the characters used to identify the device.)
The reason we are using 32768 as the start block for the device is because of the way scsi/san volume mapping uses the first few blocks of a device and subsequently causes excessive write I/O. This is better explained in the following link:
http://www.pythian.com/news/411/aligning-asm-disks-on-linux
e.g.
# fdisk /dev/sda
Command (m for help): u
Changing display/entry units to sectors
Command (m for help): p
Disk /dev/sda: 5394 MB, 5394923520 bytes
166 heads, 62 sectors/track, 1023 cylinders, total 10536960 sectors
Units = sectors of 1 * 512 = 512 bytes
  Device Boot     Start        End     Blocks  Id System
Command (m for help): n
Command action
  e  extended
  p  primary partition (1-4)
p
Partition number (1-4): 1
First sector (62-10536959, default 62): 32768
Last sector or +size or +sizeM or +sizeK (32768-10536959, default 10536959):
Using default value 10536959
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
#
Reboot the system
The command “cat /proc/partitions†(should now list extra sd partitions)
e.g.
cat /proc/partitions
major minor #blocks name
104Â Â Â Â Â Â 0Â Â 71652960 cciss/c0d0
104Â Â Â Â Â Â 1Â Â Â Â Â Â 104391 cciss/c0d0p1
104Â Â Â Â Â Â 2Â Â 71545477 cciss/c0d0p2
   8      0    5268480 sda
   8      1    5252096 sda1
   8    16    5268480 sdb
   8    17    5252096 sdb1
   8    32    5268480 sdc
   8    33    5252096 sdc1
   8    48    5268480 sdd
   8    49    5252096 sdd1
   8    64    5268480 sde
   8    65    5252096 sde1
   8    80    5268480 sdf
   8    81    5252096 sdf1
   8    96    5268480 sdg
   8    97    5252096 sdg1
   8  112    5268480 sdh
   8  113    5252096 sdh1
   8  128    5268480 sdi
   8  129    5252096 sdi1
   8  144    5268480 sdj
   8  145    5252096 sdj1
   8  160    5268480 sdk
   8  161    5252096 sdk1
   8  176    5268480 sdl
   8  177    5252096 sdl1
Etc
# ls /dev/sd*
/dev/sda  /dev/sdah /dev/sdb  /dev/sdf1 /dev/sdk  /dev/sdo1 /dev/sdt   /dev/sda1 /dev/sdai /dev/sdb1Â
/dev/sdg  /dev/sdk1 /dev/sdp  /dev/sdt1 /dev/sdaa /dev/sdaj /dev/sdc   /dev/sdg1 /dev/sdl   /dev/sdp1Â
/dev/sdu  /dev/sdab /dev/sdak /dev/sdc1 /dev/sdh  /dev/sdl1 /dev/sdq   /dev/sdu1 /dev/sdac /dev/sdalÂ
/dev/sdd  /dev/sdh1 /dev/sdm /dev/sdq1 /dev/sdv  /dev/sdad /dev/sdam /dev/sdd1 /dev/sdi   /dev/sdm1Â
# ls /dev/mapper/
ASM1Â Â Â Â Â Â Â ASM13Â Â Â Â Â ASM16p1Â ASM4p1Â Â ASM8Â Â Â Â Â OCR2Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â VOTE2
ASM10Â Â Â Â Â ASM13p1Â ASM1p1Â Â Â ASM5Â Â Â Â Â Â ASM8p1Â OCR2p1Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â VOTE2p1
ASM10p1Â ASM14Â Â Â Â Â ASM2Â Â Â Â Â Â Â ASM5p1Â Â ASM9Â Â Â Â Â VolGroup00-LogVol00Â Â VOTE3
# ls /dev/mpath
ASM1Â Â Â Â Â Â Â ASM12Â Â Â Â Â ASM14p1Â ASM1p1Â ASM4Â Â Â Â Â ASM6p1Â ASM9Â Â Â Â Â OCR2p1Â Â Â VOTE3
ASM10Â Â Â Â Â ASM12p1Â ASM15Â Â Â Â Â ASM2Â Â Â Â Â ASM4p1Â ASM7Â Â Â Â Â ASM9p1Â VOTE1Â Â Â Â Â VOTE3p1
ASM10p1Â ASM13Â Â Â Â Â ASM15p1Â ASM2p1Â ASM5Â Â Â Â Â ASM7p1Â OCR1Â Â Â Â Â VOTE1p1
edit /etc/sysconfig/oracleasm
ORACLEASM_SCANORDER=”sd”
ORACLEASM_SCANEXCLUDE=”dm”
Copy this file to each of the cluster nodes.
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