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Migrating SAN bootdisk to another Storage :

 
rveri-admin
Frequent Advisor

Migrating SAN bootdisk to another Storage :

Hi Experts, 

What are the steps to migrate SAN boot disk of 11.31 running on Superdome to another SAN storage.

 

- What are the steps and down time involved.

 

The scenario is currently the two boot disk  /dev/disk/disk05  &  /dev/disk/disk06  (And mirrored pri & alt)  connected to Storage_A. And OS is running.

 

Need to disconnect the two disk and to configure with new Lun from Storage_B.

 

Please advise, what are the steps, is it needs to be done through LVM level.

 

 

Thanks. 

6 REPLIES
Matti_Kurkela
Honored Contributor

Re: Migrating SAN bootdisk to another Storage :

I assume you know how to mirror a HP-UX system disk? This is a variation of that procedure.

This can be done on-line with no downtime, although I think you should reboot at least the first system you're migrating, to confirm that the new storage is set up appropriately for SAN boot.

 

  1. Have the SAN admin present 2 new LUNs from Storage_B. If there are any special settings for boot LUNs recommended by the SAN manufacturer, those settings should be used.
  2. Use "ioscan -fnNCdisk" (& "insf" if necessary) to confirm the system sees them.
  3. If this is an Itanium system, use idisk to partition the LUNs, and ioscan & insf again to confirm that the partition device nodes are successfully created.
  4. "pvcreate -B" the new LUNs (PA-RISC) or the new /dev/disk/diskX_p2 partitions (Itanium)
  5. "mkboot" the new LUNs, and set the appropriate boot command with "mkboot -a" on them.
  6. Use "vgextend" to add the new PVs to vg00
  7. Use "lvextend -m 2" to mirror each vg00 LV to the first new PV. You will now have a three-way mirror, with disk05, disk06 and one new PV.
  8. Use "lvreduce -m 1" to remove one set of vg00 mirrors from disk05. Now you have a regular two-way mirror, with disk06 on the old storage and one PV on the new storage.
  9. "lvlnboot -R /dev/vg00" to update the LVM boot configuration.
  10. "setboot -p /dev/disk/diskX" to make the first new LUN the primary boot disk.
  11. This would be a good point to reboot the system to test that the new storage is actually bootable. If you have already successfully booted at least one system with the same HP-UX & firmware versions and similar SAN-side configuration from the same storage and are confident that you know what you're doing, you may skip this test at this point. (But see step 19.)
  12. Use "lvextend -m 2" to mirror each vg00 LV to the second new PV. You'll again have a three-way mirror, with two PVs on the new storage and disk06 on the old storage.
  13. Use "lvreduce -m 1" to remove the set of vg00 mirrors from disk06.
  14. "lvlnboot -R /dev/vg00" to update the LVM boot configuration.
  15. "setboot -a /dev/disk/diskY" to make the second new LUN the alternate boot disk.
  16. Edit the /stand/bootconf file to correctly identify the new boot disks. (Among other things, this will allow any future patches that update the bootloader to correctly patch both the primary & alternate bootloaders.)
  17. Use "vgreduce" to remove disk05 and disk06 from vg00. If required by your site policy, overwrite the old LUNs with zeroes/random data.
  18. Use "rmsf" to remove the device nodes of disk05 and disk06 to prepare for the unpresenting of the old LUNs and/or disconnection of the old storage.
  19. Add boot testing for both primary & alternate boot disk to the tasks of the next scheduled maintenance break. If you skipped testing at step 11, you really should do this.
MK
Hiren N Dave
Valued Contributor

Re: Migrating SAN bootdisk to another Storage :

 

Or....you can assign an equal size of LUN / boot disk from another storage and use DRD (Dynamic Root Disk) to create a copy of the vg00, boot from new storage LUN and release the old storage LUN.

 

DRD documents can be downloaded from here:

http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?lang=en&cc=us&taskId=101&prodClassId=10008&contentType=SupportManual&docIndexId=64255&prodTypeId=18964&prodSeriesId=3367813

 

 

Cheers

I am an HP Employee

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rveri-admin
Frequent Advisor

Re: Migrating SAN bootdisk to another Storage :

Matti,

This is a great answer, Hats off!!  and thank you. I never thought it can be done only except the testing part. However that is crucial , except that the work is not completed, as same you have mentioned in step19.

 

Questions: 

Step17. Use "vgreduce" to remove disk05 and disk06 from vg00

 

Q-A. -Since the system is booted from one of the disk05  and or disk06 currently , how it would allow to do the vgreduce the disk,I am doubtfull if it can actually allow to reduce all the mirror from the disk bootted from. !!

 

Q-B. - How many reboot is recomended:  It seems 2 reboot required to test both the new primary and new alternate disk to boot from.

 

1. Shutdown and boot from New Primary Boot disk (of Storage B: ).   [ if Boot  ok. step 2 )

2. Shutdown and boot from New Alt           Boot disk  (of Storage B ).   [ if Boot ok.  go for final shutdown to boot using pri disk]

3. Boot standard using New Primary Boot disk,  since step 1 & 2 tested.

 

- So it seems 3 reboot requried to have a graceful testing .

 

 

Q-c: Is there anything need to be change to have MSA to P9500 boot disk migration (like in EFI or any place) , . Right now data disks are belongs to the other storage. i,e P9500 (Storage B) & works normally.

 

 

Thanks for your  valuable reply.

 

Reveri.

 

 

 

 

 

 

 

rveri-admin
Frequent Advisor

Re: Migrating SAN bootdisk to another Storage :

Hiren,

Thanks a lot for the reply and for DRD procedure steps, 

 

Got the :

Dynamic Root Disk A.3.10.* Administrator's Guide

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c02711804/c02711804.pdf

 

ll see which steps we can go through. 

 

 

Thanks.

Reveri.

Matti_Kurkela
Honored Contributor

Re: Migrating SAN bootdisk to another Storage :

> Questions: 

> Step17. Use "vgreduce" to remove disk05 and disk06 from vg00

 

> Q-A. -Since the system is booted from one of the disk05  and or disk06 currently , how it would allow to do the vgreduce > the disk,I am doubtfull if it can actually allow to reduce all the mirror from the disk bootted from. !!

 

Because all the LVs have been migrated away from disk05 and disk06, these are now just empty PVs as far as the OS is concerned: there is nothing "magic" that would require a reboot to remove them.

 

> Q-B. - How many reboot is recomended:  It seems 2 reboot required to test both the new primary and new alternate

> disk to boot from.

 

> 1. Shutdown and boot from New Primary Boot disk (of Storage B: ).   [ if Boot  ok. step 2 )

> 2. Shutdown and boot from New Alt           Boot disk  (of Storage B ).   [ if Boot ok.  go for final shutdown to boot using

> pri disk]

> 3. Boot standard using New Primary Boot disk,  since step 1 & 2 tested.

 

You can shave off one reboot by testing the new alternate boot disk first. Then reboot to the new primary boot disk, and if the system works OK it can keep running. So two reboots would be the minimum requirement.

 

> Q-c: Is there anything need to be change to have MSA to P9500 boot disk migration (like in EFI or any place) , . Right

> now data disks are belongs to the other storage. i,e P9500 (Storage B) & works normally.

 

When you use the "setboot" command on an Itanium system, you are actually changing the EFI settings, so that's already covered.

 

You should always check the storage manufacturer's compatibility information database to see if any special settings are required or recommended for each particular hardware combination for SAN boot. For the HP storage hardware, the database is known as SPOCK (Single Point Of Connectivity Knowledge): http://h20272.www2.hp.com/

 

MK
karthikbalu
Advisor

Re: Migrating SAN bootdisk to another Storage :

I would not use the LVM mirror for such tasks. On SAN it can be copied from one storage to another storage.

 

So just do a SAN copy.

Shutdown the host.

Do another final SAN copy & then remove the LUNS and present the new LUN in same order from SAN.

Just poweron the server...it boots normally. Need not to do anything.