I thought of sharing few tips on creating ASM devices on AIX which I will be helpful to Oracle DBA’s. Suppose SysAdmin gives you list of Serial numbers for LUN instead of device Name
pcmpath query device
DEV#: 33 DEVICE NAME: hdisk33 TYPE: 2107900 ALGORITHM: Load Balance
SERIAL: 75DM011<span style="color: #ff0000;"><strong>1101</strong></span>
===========================================================================
Path# Adapter/Path Name State Mode Select Errors
0 fscsi0/path0 CLOSE NORMAL 9 0
1 fscsi1/path1 CLOSE NORMAL 8 0
In case there are lot many disks, then it could be a tiring task of running above command and finding each device. You can use below code which will list name of devices and size (In MB) of disk.
for i in 1000 1100 1018 1118 1030 1130 104C 114C 1068 1168 1080 1180
do
j=`pcmpath query device|grep -p $i"$"|grep DEVICE|awk -F ":" '{print }'|awk '{print }`
k=`bootinfo -s $j`
echo $i $j $k
done
This would return following output
1000 hdisk4 65536 1100 hdisk10 65536 1018 hdisk5 65536 1118 hdisk11 65536 1030 hdisk6 65536 1130 hdisk12 65536 104C hdisk7 65536 114C hdisk13 65536 1068 hdisk8 65536 1168 hdisk14 65536 1080 hdisk9 65536 1180 hdisk15 65536
Now if you need to create new device name, you need to use mknod command and pass on major and minor numbers. Following code can be used to perform same
#export m=0
# for i in hdisk4 hdisk10 hdisk5 hdisk11 hdisk6 hdisk12 hdisk7 hdisk13 hdisk8 hdisk14 hdisk9 hdisk15
do
j=`ls -la /dev/$i |awk '{print }'|awk -F "," '{print }'`
k=`ls -la /dev/$i |awk '{print }'`
m=`expr $m + 1` ;echo "mknod /dev/asm_disk"$m "c "$j $k
done
mknod /dev/asm_disk1 c 21 4
mknod /dev/asm_disk2 c 21 12
mknod /dev/asm_disk3 c 21 13
mknod /dev/asm_disk4 c 21 15
mknod /dev/asm_disk5 c 21 5
mknod /dev/asm_disk6 c 21 6
mknod /dev/asm_disk7 c 21 8
mknod /dev/asm_disk8 c 21 7
mknod /dev/asm_disk9 c 21 14
mknod /dev/asm_disk10 c 21 10
mknod /dev/asm_disk11 c 21 9
mknod /dev/asm_disk12 c 21 11
Now you can change the ownership to oracle:dba and permission to 660. I have 12 disks , so using list of 12 variables. In case you have more disks , then you can add more variables
# for i in 1 2 3 4 5 6 7 8 9 10 11 12 do chown oracle:dba /dev/asm_disk$i chmod 660 /dev/asm_disk$i done crw-rw---- 1 oracle dba 21, 11 Jan 28 17:10 /dev/asm_disk12 crw-rw---- 1 oracle dba 21, 9 Jan 28 17:10 /dev/asm_disk11 crw-rw---- 1 oracle dba 21, 10 Jan 28 17:10 /dev/asm_disk10 crw-rw---- 1 oracle dba 21, 14 Jan 28 17:04 /dev/asm_disk9 crw-rw---- 1 oracle dba 21, 7 Jan 28 17:04 /dev/asm_disk8 crw-rw---- 1 oracle dba 21, 8 Jan 28 17:04 /dev/asm_disk7 crw-rw---- 1 oracle dba 21, 6 Jan 28 17:04 /dev/asm_disk6 crw-rw---- 1 oracle dba 21, 5 Jan 28 17:04 /dev/asm_disk5 crw-rw---- 1 oracle dba 21, 15 Jan 28 17:04 /dev/asm_disk4 crw-rw---- 1 oracle dba 21, 13 Jan 28 17:04 /dev/asm_disk3 crw-rw---- 1 oracle dba 21, 12 Jan 28 17:04 /dev/asm_disk2 crw-rw---- 1 oracle dba 21, 4 Jan 28 17:04 /dev/asm_disk1
In case you need to use same logic for creating OCR and Voting disks on RAC system, replace /dev/asm with /dev/ocr or /dev/voting . I hope this would save some time and also prevent errors 
In case you have disks in ordered number,say 53 to 62 then you can also use for loop as below.
#bash
bash-3.00#
#export m=0
#for ((i=53;i<=62;i++))
do
j=`ls -la /dev/hdisk$i |awk '{print }'|awk -F "," '{print }'`
k=`ls -la /dev/hdisk$i |awk '{print }'`
m=`expr $m + 1` ;echo "mknod /dev/asm_disk"$m "c "$j $k
done
#for ((i=1;i<=10;i++))
do
chown oracle:dba /dev/asm_disk$i
chmod 660 /dev/asm_disk$i
done
I would suggest anyone using the scripts to first check in a test environment.
Instead of running the mknod, why not just do an ln of the rdisk:
(these two should be the same)
mknod /dev/asm_disk1 c 21 4
ln rhdisk4 asm_disk1
If you can find a way to increment the disk # easily, you would be golden and it would save a few lines
John,
You can use soft links but oracle recommend's using mknod to create link. You can use following code to increment disk#
for i in 1960 20CD 20CE 20CF 21CD 21CE
do
j=`pcmpath query device|grep -p $i"$"|grep DEVICE|awk -F ":" '{print $3}'|awk '{print $1}`
k=`bootinfo -s $j`
a=`ls -la /dev/$j |awk '{print $5}'|awk -F "," '{print $1}'`
b=`ls -la /dev/$j |awk '{print $6}'`
b=`echo $b |awk '{x=$0+0; print x}'`
if [ b -le 1 ]
then
b=`ls -la /dev/$j |awk '{print $5}'|awk -F "," '{print $2}'`
fi
if [ m -le 8 ]
then
m=`expr $m + 1` ;echo "mknod /dev/asm_disk0"$m "c "$a $b
else
m=`expr $m + 1` ;echo "mknod /dev/asm_disk"$m "c "$a $b
fi
done
-Amit
Hi there,
check out this post, might be a copy of yours!
http://gjilevski.wordpress.com/2010/02/16/creating-asm-devices-on-aix/
The author has copied other user’s material in countless occasions without giving credit.
Yeah Martin. This seems to be exact copy.I have put a comment, let’s see what he has to say.
Thanks for pointing it.
Cheers
Amit
Thanks to your instructions, I was able to get this working once before. However, I am trying to do it again and I’m running into trouble. When I try to create the ASM disk group during the grid infrastructure installation, the disks do not show up. In my case, the disks I’m trying to add are EMC powerpath disks. Any idea what could cause them to not show up?
Hi Lucas,
If you have set set asm_diskstring parameter to correct value i.e, something like /dev/rhd* (in case of emcpowerpath) the disks should be visible to you.
If still the disks are not getting shown please check Metalink note 1174604.1 “ASM Is Not Detecting EMC PowerPath Raw Devices Or Regular Raw Devices On AIX” as there could be some permissions issue.
Regards,
Saurabh Sood