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Query Regarding ASM in HP-UX V 11.11

Md. Minhaz Khan
Super Advisor

Query Regarding ASM in HP-UX V 11.11

Dear ALL,

We are newly introduced Oracle ASM in one of our HP-UX server(OS Version: B.11.11 & model:RP4440).But when DBA asked new raw disks for ASM database, we just assign LUNs from EMC storage (CX-340) to that server and give them(DBA) raw disks(ex:/dev/rdsk/c20t0d1) and change the ownership to "oracle:dba". DBA team then add this LUN to *.asm_diskstring parameter.

But now we want to do as follows:
1) Make soft link of all raw disks. For ex:
#mkdir /dev/asm
#ln -s /dev/rdsk/c4t0d1 /dev/asm/DG1ASM1
#ln -s /dev/rdsk/c5t0d2 /dev/asm/DG1ASM2
...............
2)Change ownership & permission:
#chown -h oracle:dba /dev/asm/*
#chown oracle:dba /dev/asm/*
#chmod 660 /dev/asm/*

3)Now assign a Regular expression in the ASM parameter file. For ex:
.......
*.asm_diskstring='/dev/asm/DG1ASM*'

My 2nd query is, we have 2 FC switches,2 HBA per server and powerpath(EMC,CX-340) also installed. Now for LUN "/dev/rdsk/c4t0d1" we have another 3 alternate links. So as we softlink only "/dev/rdsk/c4t0d1" disk, if this path become faulty then what happen?is it auto failover or not? Did we also need to modify ownership of alternate links to "oracle:dba"? So that if auto failover occurs then oracle grep alternate links.

Please don't give me any links.

Thanks
Minhaz
1 REPLY
Matti_Kurkela
Honored Contributor

Re: Query Regarding ASM in HP-UX V 11.11

Yes, that is a nice description of your Oracle/ASM disk setup, but you left out the actual first question.

I guess you might be trying to ask something like "does this seem OK to you?".

Yes, I think it will work, *as long as* the SAN configuration is not changed, and the system is not rebooted while the /dev/rdsk path you've configured for ASM is not accessible.

I also think your set-up will require quite a bit of work when it's time to migrate to another storage system.

You might wish to Google with search words "Oracle ASM HP-UX best practice".

I would like run the same search in Oracle Metalink too, but I don't have access to it at the moment.

---

For your second question, I have to say you obviously haven't understood how PowerPath works. I think it is irresponsible to use PowerPath and not have this basic knowledge. So please think of the rest of this post as "remedial training." :)

Log on to EMC Powerlink and download "PowerPath Product Guide" and "PowerPath for HP-UX Installation and Administration Guide".

Read the "PowerPath Overview" chapter from the first one to make sure you understand PowerPath concepts and know the names PowerPath uses for different things. Pay attention to what is said about "native devices": it is going to be important.

Then read "PowerPath for HP-UX Installation and Administration Guide". The most important chapter is "PowerPath administration on HP-UX". Its first sub-chapter is titled "Device Naming" and it provides the answer to your 2nd question - but you probably won't realize it unless you've read PowerPath Overview from the Product Guide first.

If you don't have a Powerlink account, ask your SAN admin to download the documents for you. Also ask your SAN admin to help you to create a Powerlink account for yourself - as a sysadmin, you *will* need to refer to EMC documents (HBA/driver version compatibility lists, PowerPath release notes, etc.) from time to time.

No links, because I cannot provide them: EMC Powerlink requires a login and seems to use non-reusable URLs.

MK
MK