it-rex
asked on
AIX LUN major minor vs serial#
we have a RAC system with LUNS attacjed to both nodes we have created ASM aliases using major and mainor number..
ASM1 till ASM 10 are correctly showing the major minor numbers in both nodes...
and everything is running fine..
and this is best practice by IBM and ORACLE.
but we have a new Jr SA who is saying this is wrong as although major and minor are the same for each LUN on both Nodes the Lun Serila number is different.
we know that the configuartion is correct.
but how LUN serial could be different and major minor are identical?
ASM1 till ASM 10 are correctly showing the major minor numbers in both nodes...
and everything is running fine..
and this is best practice by IBM and ORACLE.
but we have a new Jr SA who is saying this is wrong as although major and minor are the same for each LUN on both Nodes the Lun Serila number is different.
we know that the configuartion is correct.
but how LUN serial could be different and major minor are identical?
SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
So what would explain having 2 LUNS shared between 2 lpars
With same major and minor
But lscfg shows different lun names
??????
With same major and minor
But lscfg shows different lun names
??????
ASKER
both
hdisk8@node1
and
hdisk4@node2
they have the major and minor numbers
ls -la hdisk8
brw-rw---- 1 grid asmadmin 18, 14 Jan 17 09:02 hdisk8
ls -la hdisk4
brw-rw---- 1 grid asmadmin 18, 14 Jan 17 09:11 hdisk4
@node1
lscfg -vpl hdisk8
hdisk8 U9179.MHD.10854A0-V42-C42- T1-W500507680140B9D7-L3200000 0000000 MPIO FC 2145
Manufacturer.............. ..IBM
Machine Type and Model......2145
ROS Level and ID............0000
Device Specific.(Z0)........00000 6326818100 2
Device Specific.(Z1)........02006 0c
Serial Number...............60050 768018305C FC00000000 0000B8C
@node2
lscfg -vpl hdisk4
hdisk4 U9179.MHD.10854A0-V44-C44- T1-W500507680140B9D7-L2200000 0000000 MPIO FC 2145
Manufacturer.............. ..IBM
Machine Type and Model......2145
ROS Level and ID............0000
Device Specific.(Z0)........00000 6326818100 2
Device Specific.(Z1)........02006 0c
Serial Number...............60050 768018305C FC00000000 0000B7C
As you have mentioned the I think I see both
The WWN and the LUN are the same.
but what is the line that says
Serial Number means and what it signifies?
hdisk8@node1
and
hdisk4@node2
they have the major and minor numbers
ls -la hdisk8
brw-rw---- 1 grid asmadmin 18, 14 Jan 17 09:02 hdisk8
ls -la hdisk4
brw-rw---- 1 grid asmadmin 18, 14 Jan 17 09:11 hdisk4
@node1
lscfg -vpl hdisk8
hdisk8 U9179.MHD.10854A0-V42-C42-
Manufacturer..............
Machine Type and Model......2145
ROS Level and ID............0000
Device Specific.(Z0)........00000
Device Specific.(Z1)........02006
Serial Number...............60050
@node2
lscfg -vpl hdisk4
hdisk4 U9179.MHD.10854A0-V44-C44-
Manufacturer..............
Machine Type and Model......2145
ROS Level and ID............0000
Device Specific.(Z0)........00000
Device Specific.(Z1)........02006
Serial Number...............60050
As you have mentioned the I think I see both
The WWN and the LUN are the same.
but what is the line that says
Serial Number means and what it signifies?
It seems that these nodes are running as LPARS with dedicated HBAs (or NPIV) on the same hardware (Power 780).
Anyway, the LUN number is not the same! hdisk8 has LUN 32 and hdisk4 has LUN 22.
The serial number is composed of parts of the WWN and some more information. This number is unique, and is also different, as you said.
So I'm rather sure that these are different disks!
The major/minor numbers aren't of any significance across nodes, they're only used internally. Up to now I wasn't aware that you could create an ASM diskgroup using major/minor! Or do you mean the "/dev/hdiskx" entry instead?
There is a really unique disk identifier at a higher level in AIX, which is the PVID. This identifier is written on the disk and cannot change.
Run
lspv
on the nodes and search for hdisk4 and hdisk8, respectively. If the displayed IDs (second column) are different you can be really sure that these disks are not the same!
Anyway, the LUN number is not the same! hdisk8 has LUN 32 and hdisk4 has LUN 22.
The serial number is composed of parts of the WWN and some more information. This number is unique, and is also different, as you said.
So I'm rather sure that these are different disks!
The major/minor numbers aren't of any significance across nodes, they're only used internally. Up to now I wasn't aware that you could create an ASM diskgroup using major/minor! Or do you mean the "/dev/hdiskx" entry instead?
There is a really unique disk identifier at a higher level in AIX, which is the PVID. This identifier is written on the disk and cannot change.
Run
lspv
on the nodes and search for hdisk4 and hdisk8, respectively. If the displayed IDs (second column) are different you can be really sure that these disks are not the same!
ASKER
With ASM on AIX we can not have PVID it is a requirement for pvid to be null
OK,
but the disks come from the same storage server (SVC) and have different LUNs, so they are different disks.
Moreover, thay have different serial numbers.
You can check these numbers on the SVC by means of the "lshostvdiskmap" command.
Here, too, you will see that it's two different disks.
but the disks come from the same storage server (SVC) and have different LUNs, so they are different disks.
Moreover, thay have different serial numbers.
You can check these numbers on the SVC by means of the "lshostvdiskmap" command.
Here, too, you will see that it's two different disks.
ASKER
thanks all
ASKER
Will it be possible that output of lscfg will show 2 different serial numbers.