topic Re: TEST DR in Operating System - Tru64 Unix

TEST DR

Srivathsan — Fri, 26 Nov 2004 06:25:34 GMT

The Servers TARA ( DC1 ) and TARA2 ( in DC2 ) running Tru64 Unix V 5.1 with PK 6 are in a SAN Fabric.

The Fabric switches are 2 x 8-port Manageable Compaq SANSwitches.

The Servers are connected to the HSG80 storage in SAN in such a way that there are 4 paths available to the storage from the server.

Both the Data and O/S disks are in the HSG80 based storage subsystem.

The HSG80 has multibus failover configuration ( 2 controllers in each HSG80 ).

The HDDs are in a MA8000.

There is no Zoning configured on the SAN Switch and the contention for Logical Units provided by the HSG80 is resolved by the access policy configured in the HSG80 Controllers.

The SAN diagram, list of LUNS and the details of each LUN is provided in the attachment.

WHAT I INTEND TO DO FOR DR TESTING -

1. INSTALL ANOTHER SERVER TARBK ( WITH 2 KGPSA-CA CARDS ) AND INTERNAL ROOT DISK ENCAPSULATED IN LSM.

2. SHUTDOWN TARBK TO SRM LEVEL AND CONNECT THE FIBER FROM ONE KGPSA TO ONE SAN SWITCH AND FROM THE OTHER KGPSA TO THE OTHER SAN SWITCH.

3. ON THE FOUR NEW CONNECTIONS ON EACH OF THE HSG80s CONFIGURE THE UNIT OFFSET TO 0 ( SO AS TO BE ABLE TO ACCESS ALL LUNs ON THESE NEW CONNECTIONS )

4. ENABLE ACCESS TO ALL LUNs ON ALL THE NEW CONNECTIONS ( SET ENABLE ACCESS PATH ALL )

5. SHUTDOWN TARA ( SO, THE DATA DISK GROUP IS CLEARLY DEPORTED )

6. CHECK SHOW DEV AT THE SRM LEVEL OF TARABK AND ENSURE THAT IT IS ABLE TO SEE THE DATA LUNs

7. BOOT OFF THE INTERNAL ROOT DISK IN TARABK AND IMPORT THE DATADG IN THE HSG.

8. MOUNT THE DATA FILESETS MANUALLY AND CHANGE THE DNS SUCH THAT ANY USER TRYING TO CONNECT TO TARA IS FORWARDED TO TARABK.

QUESTIONS

1. ANY CONFIGURATIONS REQUIRED IN STEP 3 ON THE NEW CONNECTIONS

2. IN STEP 2 DO I NEED TO RUN ANY WWIDMGR COMMANDS ??

ANY INPUTS / THOUGHTS / GOTCHAS / POINTERS ARE WELCOME !!

Re: TEST DR

Srivathsan — Fri, 26 Nov 2004 06:27:08 GMT

Oops...forgot the attachment

Here it is..

Thanks
Srivathsan

Re: TEST DR

Alexey Borchev — Wed, 01 Dec 2004 10:50:24 GMT

1) Please write down on a paper /etc/fdmns
directory. You'll need it to mount ADVFS filesystems in the new system.
It's recommended to have hard-copy of the files/links of the dir.

2) Take care of /etc/passwd .

3) In my site, I am using one 'native' IP address (x.x.x.1) to access server, + alias IP address (x.x.x.2) as IP-address of Your application (for example, Oracle database). All users come to x.x.x.2
The application address x.x.x.2 is assigned to one of Your servers as alias Ip address.
ifcofig alias x.x.x.2 netmask 255.255.255.0
see man ifconfig.
Then You can re-assign alias to any other server at any moment.

4) I wolud try first to do easier test:
-create small LUN on your storage, give it to TARA, create fielsystem, put some files there.
- Unmount filesystem, configure your storage to give asses to the LUN to TARBK
- Startup TARBK, try to mount the disk, see if the data there.
You can do this without affecting Your users.

Re: TEST DR

Srivathsan — Fri, 03 Dec 2004 04:17:19 GMT

Hi,

Tested with a disk ( in the shared storage ) unused in production.

Was able to move the diskgroups from prod. to the test and back to the prod machine.

Just a quick security question.

My test disks are visible to both the prod and test machines ( Allowed by HSG80 connections UNIT_OFFSET and LUN ENABLE_ACCESS_PATH ) even if i had the filesystem on the test disks mounted on the test server i was able to zero the disklabel ( disklabel -z ) from the production server.

So that means , I will normally have to keep the LUNs invisible from the test server and only in the event of a DR ( or a DR test ) that i will have to enable access for the LUNs to the Test Server ??

What should i be tweaking ...?? The HSG80 LUN ENABLE_ACCESS_PATH or the Connections from the Test Server( UNIT_OFFSET )for this purpose

Re: TEST DR

Uwe Zessin — Fri, 03 Dec 2004 06:59:34 GMT

I would use ENABLE_ACCESS_PATH, because that is the purpose.

UNIT_OFFSET was useful / required in those times when a system had only SCSI-2 drivers and could not address more that 8 LUNs on a fibre channel target. I really, really, would not use it today as most system can work with large LUNs - meaning it can potentially address any HSG unit starting at UNIT_OFFSET and ending at 199.

Re: TEST DR

Alexey Borchev — Fri, 03 Dec 2004 07:07:20 GMT

You may tweaking with zone configuration on SAN switches as well.

Re: TEST DR

Srivathsan — Wed, 05 Jan 2005 11:23:04 GMT

Thanks All.

Tweaked the ENABLE_ACCESS_PATH and it was smooth.