topic Re: How to change persistent DSF name in HPUX 11.31 in Operating System - HP-UX

How to change persistent DSF name in HPUX 11.31

Sajjad Premier — Thu, 12 Aug 2010 08:49:11 GMT

Dear All,

we have created virtual disk in HP EVA 4100 and present this volume to two HPUX 11.31 servers. Oracle wants same persistent DSF names on both servers. Oracle used raw partitions for installation of ASM oracle RAC.

Both servers names are below:

proddb1:

# ioscan -m dsf /dev/rdisk/disk90
Persistent DSF Legacy DSF(s)
========================================
/dev/rdisk/disk90
/dev/rdsk/c5t0d7
/dev/rdsk/c3t0d7
/dev/rdsk/c10t0d7
/dev/rdsk/c8t0d7

proddb2:

# ioscan -m dsf /dev/rdisk/disk87
Persistent DSF Legacy DSF(s)
========================================
/dev/rdisk/disk87
/dev/rdsk/c10t0d7
/dev/rdsk/c3t0d7
/dev/rdsk/c8t0d7
/dev/rdsk/c5t0d7

Please help to resolve this issue.

Thanks & Kind Regards,

Sajjad Ahmed

Re: How to change persistent DSF name in HPUX 11.31

VVS — Thu, 12 Aug 2010 09:04:11 GMT

Please check below doc,

www.docs.hp.com/en/MassStorageStack/The_Next_Generation_Mass_Storage_Stack.pdf

Regards,
VVS

Re: How to change persistent DSF name in HPUX 11.31

kevin_m — Thu, 12 Aug 2010 23:56:10 GMT

I created custom device files using mksf for this exact reason (RAC cluster with raw devices). You can assign specific ownership and permissions as required by Oracle without worrying about them getting reset by the OS. For example:

mksf -C disk -H -r /dev//asm/db01
chown oracle:dba /dev//asm/db01
chmod 660 /dev//asm/db01

When you run an ioscan afterwards you'll see the unique hardware paths for the LUN on each server as well as the name you assigned. Then point ASM_DISKSTRING to /dev//asm/* and it will be same for both nodes.

- Kevin

Re: How to change persistent DSF name in HPUX 11.31

GPissutto — Fri, 13 Aug 2010 02:13:48 GMT

# io_redirect_dsf -d /dev/disk/disk14 -n /dev/disk/disk28

not the case, but could be useful sometime, so also check:
# scsimgr replace_wwid â D /dev/rdisk/disk14

Re: How to change persistent DSF name in HPUX 11.31

Sajjad Premier — Fri, 13 Aug 2010 05:08:49 GMT

Dear Kevin,

Thanks for your support.

I have already sent actual DSF persistent names on both servers. Can you please exact commands as per given DSF persistent names of both servers proddb1 and proddb2?

Also please tell me how we can get hardware paths of both servers?

Also tell me please these commands run on both servers or on any of one server?

Thanks & Kind Regards,

Sajjad Ahmed

Re: How to change persistent DSF name in HPUX 11.31

kevin_m — Fri, 13 Aug 2010 12:02:21 GMT

I'll give an example for an ASM disk device /dev/disk/disk344 and a database we've named erptrn. Run an ioscan on both servers with the -N option to get the agile view.

ioscan -fnNC disk

Here's the resulting details for that particular disk on server 1:

disk 344 64000/0xfa00/0x8c esdisk CLAIMED DEVICE DGC CX500WDR5
/dev/disk/disk344 /dev/rdisk/disk344

The other server will probably have a different path and disk number but it doesn't matter. Insert the unique hardware path (-H option) into the mksf command on both servers:

mksf -C disk -H 64000/0xfa00/0x8c -r /dev/erptrn/asm/db01 # server 1
mksf -C disk -H 64000/0xfa00/0x8f -r /dev/erptrn/asm/db01 # server 2

When you run ioscan again it will also list your custom device file for that disk in addition to the system generated DSFs.

disk 344 64000/0xfa00/0x8c esdisk CLAIMED DEVICE DGC CX500WDR5
/dev/disk/disk344 /dev/erptrn/asm/db01 /dev/rdisk/disk344

So as far as Oracle is concerned, the DSF becomes /dev/erptrn/asm/db01 for this example instead of using /dev/disk/disk344. Use whatever naming convention you want but make sure to chown/chmod as listed above.

Kevin

Re: How to change persistent DSF name in HPUX 11.31

Sajjad Premier — Thu, 02 Sep 2010 07:05:33 GMT

Dear Kevin,

Thanks for response.

Sorry for delayed reply.

My question is:

What about Legacy DSF's because when we enter the below command:

ioscan -m dsf /dev/rdisk/disk87

After running command, disk87 are showing four paths.

/dev/rdsk/c10t0d7
/dev/rdsk/c3t0d7
/dev/rdsk/c8t0d7
/dev/rdsk/c5t0d7

Please clarify when we will implement your solution which persisten DSF is showing these four paths. Please take your example as illustrated in previous email.

Also please calrify you will use /dev to create custom disk. c
Your favor in this regard is highly appreciated.
Can we use the /dev/rdisk path for creating custome disk by mksf?

Thanks & Kind Regards,

Sajjad Ahmed

Re: How to change persistent DSF name in HPUX 11.31

kevin_m — Thu, 02 Sep 2010 13:12:05 GMT

You may see multiple legacy DSFs for each disk because of multipathing in 11.31. I basically ignore all those older device files and only reference the hardware path (-H) for mksf as noted in my example. Make sure you use the -N option for ioscan. The custom DSF you create will not be in the rdisk format but instead whatever name applies to your environment. That allows the operating system DSF and the Oracle DSF to have separate ownership and permissions even though they both reference the same LUN. The custom DSF could begin with /dev/oracle or /dev/db_A for example. The additional directory in /dev will automatically be created by the mksf command.

Re: How to change persistent DSF name in HPUX 11.31

Sajjad Premier — Fri, 03 Sep 2010 05:54:35 GMT

Dear Kevin,

Thanks for your response.

Sorry My question is:

When we will create the custom DSF by mksf
-H. Then Custom DSF will show automatically four paths when we will enter the ioscan command by entering -N. Please clarify. We have two SAN switches and two FC cards install in two servers thats why servers are shwoing four legacy paths as illustrated above. Customer wants oracle ASM on raw partitions. In HPUX 11.31, we use native multipathing. If one FC card or SAN switch will fail then traffic will not be disturbed.

I know very well that we will give oracle permissions to custom DSF which will create by mksf command.

Thanks & Kind Regards,

Sajjad Ahmed

Re: How to change persistent DSF name in HPUX 11.31

kevin_m — Fri, 03 Sep 2010 12:25:00 GMT

Only work with multipath devices using 'ioscan -fnNC disk'. That's where you will find the hardware path to use with mksf. The legacy device files are irrelevant and do not matter. The end result is 3 devices for each LUN, 2 created by the operating system and 1 that you created to use with ASM. Here's an example:

disk 344 64000/0xfa00/0x8c esdisk CLAIMED DEVICE DGC CX500WDR5
/dev/disk/disk344 /dev/erptrn/asm/db01 /dev/rdisk/disk344

We also have 2 HBA's and 2 switches and multipathing definitely works if we lose one path.