Oracle ASM and RAW devices.

[tom quach_1]

Hi All,

Please advice how i can use my raw devices for the oracle ASM.
i have HP Storageworks Virtual Array 7110.
when i created a LUN for 10Gb for the system. it generated 2 devices
/dev/rdsk/c6t0d2
/dev/rdsk/c4t0d2

for Oracle ASM, i just need to change ownership and add to Oracle ASM. But which one?
If someone has done this before.
Please advice.

Thanks in advance.
Regards,
Tom

[Sandman!]

They two device files that you are seeing look like Alternate Paths to the same LUN. Do you have two HBAs on your HPUX server? Just add one of them paths to the Oracle ASM software and you should be fine. Please post the output of the following command:

# ioscan -funC ext_bus

[A. Clay Stephenson]

These are PROBABLY devices nodes which correspond to the same physical LUN. It is common for arrays to create multiple paths to the same LUN so that if one path fails an alternate is available. I say probably because I didn't carry out the operation but your array management software should be able to tell you. Another method (if you know these these are indeed unused LUN's) is to use dd to copy data using one of the device nodes and use dd to read it back using the other device node. If the data match, you are talking to the same physical LUN.

[tom quach_1]

Thanks Sandman and A. Clay.

there are 2 HBA on the host.
yes i could pick any device for the ASM and it would work. But i worry about fail over when one path goes dead.
yes, these 2 devices are from the same physical LUN.
i guess the question is how to make it failover when ASM only know of 1 device. we have EVA3000 with securePath and it taking care of this by combine the 2 devices into one. is there a similar way to do it.

#ioscan -funC ext_bus
Class I H/W Path Driver S/W State H/W Type Description
=========================================================================
ext_bus 0 0/0/1/0 c8xx CLAIMED INTERFACE SCSI C896 Ultra Wid
e LVD
ext_bus 1 0/0/1/1 c8xx CLAIMED INTERFACE SCSI C896 Ultra Wid
e Single-Ended
ext_bus 2 0/0/2/0 c8xx CLAIMED INTERFACE SCSI C87x Ultra Wid
e Single-Ended
ext_bus 3 0/0/2/1 c8xx CLAIMED INTERFACE SCSI C87x Ultra Wid
e Single-Ended
ext_bus 4 0/10/0/0.8.0.110.0 fcparray CLAIMED INTERFACE FCP Array Int
erface
ext_bus 5 0/10/0/0.8.0.255.6 fcpdev CLAIMED INTERFACE FCP Device In
terface
ext_bus 6 0/12/0/0.8.0.108.0 fcparray CLAIMED INTERFACE FCP Array Int
erface
ext_bus 7 0/12/0/0.8.0.255.6 fcpdev CLAIMED INTERFACE FCP Device In
terface


and these are 2 path from 2 HBA with the same physical LUN

disk 5 0/10/0/0.8.0.110.0.0.2 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c4t0d2 /dev/rdsk/c4t0d2

disk 6 0/12/0/0.8.0.108.0.0.2 sdisk CLAIMED DEVICE HP A6189B
/dev/dsk/c6t0d2 /dev/rdsk/c6t0d2



Thanks,
Tom

[Sandman!]

Using LVM should provide you with the fault tolerance you need in case the primary path goes down. You can read more about it in this thread:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=692210

~hope it helps

[tom quach_1]

Thanks Sandman.

if i use LVM, pvlink will be perfectly fine. In my case, i use Raw devices in Oracle ASM. i could use one link for the ASM and it would work fine also, but in case this link dies there is no failover for the survive link.
how to combine the 2 path to become one as securepath on my EVA3000 does?

Thanks,
Tom

[Sandman!]

You are right Tom...don't know what I was thinking. Somehow got the lvols confused with the raw device special files. Imho you need to install the Auto Path software. It is the Secure Path equivalent on VA 7000 class of storage systems. Read more about it in the HP whitepaper below:

http://h20000.www2.hp.com/bc/docs/support/SupportManual/lpg28858/lpg28858.pdf?jumpid=reg_R1002_USEN

~cheers

[tom quach_1]

Hello,

now i got autopath working but i still have to devices.
please advice how i can map it so it present me with one device.
thanks in advance.
Tom,


#autopath display -l 6F00-0200-0000-0000-1D00-0000-0000-0000

==================================================================
HPswsp Version : A.3.0F.02F.02F
==================================================================
Array WWN : 060B-0000-151A-6F50

==================================================================
Lun WWN : 6F00-0200-0000-0000-1D00-0000-0000-0000
Virtual Device File : /hpap/dsk/hpap0
Load Balancing Policy : Round Robin
Lun Timeout : Infinite Retry (-1)
==================================================================
Device Path Status
==================================================================
/dev/dsk/c4t0d2 Active
/dev/dsk/c6t0d2 Active

[Duncan Edmonstone]

Tom,

You already have a single device:

Virtual Device File : /hpap/dsk/hpap0

You just need to change you ASM_DISKSTRING parameter in your ASM instance to point to /hpap/dsk

I guess you may need to chnage the permissions/ownership on that device as well

HTH

Duncan

[Yogeeraj_1]

Hi Tom,

Now that you have identified the Virtual Device File : /hpap/dsk/hpap0

The Oracle data directory could be setup the following way:
$ ln -s /hpap/dsk/hpap0 /u02/oradata/asmdisks/disk00
$ ln -s /hpap/dsk/hpap1 /u02/oradata/asmdisks/disk01
$ ln -s /hpap/dsk/hpap2 /u02/oradata/asmdisks/disk02
$ ln -s /hpap/dsk/hpap3 /u02/oradata/asmdisks/disk03

And the following command needs to be executed after each reboot:
# chown oracle.dba /u02/oradata/asmdisks/*

You need to ensure that the ownership of block devices is changed to oracle:dba or oracle:oinstall. Otherwise Oracle will not be able to access the block devices and ASM disk discovery will not list them. (NB. In linux, we had to ensure that the ownership of block devices was set after each reboot since Linux changes the ownership of block devices back to "brw-rw---- 1 root disk" at boot time. You will need to verify if the behaviour is the same on HP-UX).

and finally, to create your ASM disk group, you will need to set the Disk Discovery Path to "/u02/oradata/asmdisks/*"

Hope this helps too!

kind regards
yogeeraj