Mirroring

[Helen French]

Hi all,

I am going for an OS upgrade on K class server from 10.20 to 11.0. It will be a cold install. Right now i have the root vg mirrored. I will be installing the 11.0 on one of the disk. At this point, after the installation, will there be any problem for me to import the old mirror HDD to the new system (for accessing the configuration files)? And I assume in case if i want to go back to 10.20, i just need to boot from the old mirror and remirror it. If everything works fine, then i will mirror the new root VG to the old mirror disk.

Am I thinking correct here ? Any comments or suggestions will be appreciated !

Thanks!
Shiju

[Sanjay_6]

Hi Shiju,

I don't think you can import the old mirror to the new OS. you can recreate the mirror on the old mirror disk if you want. The revese is possible, in case you want to revert back to 10.20, you can boot through the mirror and then do a vgcfgrestore for the primary disk and then do a vgsync to sync the data from the mirror to the primary disk.

To access the configuration files from the old os, you should take a backup on a removable media and after installing the new os on the disk, restore the backed up files and then update the configuration.

Hope this helps.

Regds

[S.K. Chan]

I would make a copy of 10.20 configuration files that I need (to a tape or remote system) and then later after loading 11.0 get access to them (restore from tape or NFS mount).
In my opinion this would be less complicated. Maybe someone would share a better way of doing it ..

[Helen French]

Hi,

I have both soft and hard copy of the configuration files.

Thanks for the comments ... more inputs are welcome ..points to follow ..

Shiju

[Darrell Allen]

Hi Shiju,

Be sure you make an Ignite backup (or 2) before starting.

I'm also interested in knowing if you can vgimport a 10.20 boot disk onto an 11.0 system. Seems probably but I've not tried it.

Let us know if it works.

Darrell

[A. Clay Stephenson · Accepted solution]

Here is what I would do.

1) On the disk that you plan to be your new boot disk, while still under 10.20 do lvreduces to remove all the lvol mirrors (-m 0) but make sure that you specify the disk you plan to plan your 11.0 boot disk.

2) vgreduce vg00 to remove what will be the new boot disk.

3) vgexport -m /tmp/vg00.1020.map -p /dev/vg00
4) ftp or rcp /tmp/vg00.1020.map to another box (unless your lvols are simply lvol1, lvol2, ... so that you won't need a mapfile)

5) Do a vgdisplay -v and a bdf and pipe the outputs to lp so that you have a hardcopy of what the 10.20 vg00 looked like.

You can now load 11.0 on what was the mirror and then you can import the old vg00 disk(s) to another VG and mount the filesystems on something like /oldroot, /oldusr, ...

Regards, Clay

[Sanjay_6]

Hi Shiju,

If you have any data VG's on the old system, Do a vgexport and save the map files, you can then use these map files to import the VG into the new configuration if you still want to use your old VG's. Ignite backup from the Old system as suggested by Darrell is a good option in case you need to back out from the change and your mirror does not work for some reason.

Hope this helps.

Regds

[Patrick Wallek]

Yes, you should be able to vgimport the old 10.20 boot disk into your 11.0 system once you are finished with the installation.

The steps I would do to import the 10.20 disk:

1) mkdir /dev/vg01
2) mknod /dev/vg01/group c 64 0x010000
3) vgimport vg01 /dev/dsk/c?t?d0
4) mkdir /1020root
5) mount /dev/vg01/lvol? /1020root/?

That should do it for you.

[James R. Ferguson]

Hi:

Since your doing a cold-install, the liklihood of success is very, very high.

The number of configuration files is relatively small. I gather what I want under a directory that I then copy to tape and load after the cold-installation.

I'd start by vgreducing the mirror and cold install to the freed disk. In the event that you need to fall back to 10.20, boot from that disk. If not, and your happy with your configuration, you can mirror your 11.x disk to the old 10.20 one.

In my opinion, this is straightforward and safe.

Regards!

...JRF...

[Helen French]

Hi all,

Thanks for the answers. Just few questions:

Clay and JRF,

After I do a mirror reduce and vgreduce, do I need to run 'lvlnboot' or 'lvrmboot' to update the boot info ?

Sanjay,

It is not necessary to export the data VG's as I am using standard naming conventions ( lvol1, lvol2..etc) rt ? I assume, even if it is not exported, i will be able to import it on 11.0.

Also i will make sure that i have the recovery tapes. I will let you know about the steps and status of this, once it is done.

Shiju

[Sanjay_6]

Hi Shiju,

If you wish to use the existing data VG's then it would be better if you do a vgexport for the existing data VG's and take a backup of the map files and import the VG into the new configuration using the map file. It doesn't matter whether you are using lvol's to name your lv's or you have different names for the lv's. It is safer to export a map file for a vg and then import the vg info from the map file.

Like others have already suggested, you can import the old 10.20 mirror disk into the new system as a different VG, that is always possible.

Hope this helps.

Regds

[Patrick Wallek]

It probably would be a good idea to do an 'lvlnboot -v' after you get done removing the mirrors to make sure your boot information is correct. If it is, no worries. If not, then do the lvlnboot commands necessary to fix whatever is wrong.

[James R. Ferguson]

Hi:

I agree with Patrick that running 'lvlnboot -v' to visually verify your configuration is always a good choice.

As for any requirement to update the boot information, there is no explicit action necessary on your part. You will note from the man pages: "This command should be run in recovery mode (-R) whenever the configuration of the root volume group is affected by one of the following commands: lvextend, lvmerge, lvreduce, lvsplit, pvmove, lvremove, vgextend, or vgreduce... Starting with HP-UX Release 10.0, this is done automatically."

With regard to the 'vgexport' question, it is not necessary to export to import under your new OS. Remember that the mapfiles are really intended for cases where you do not use standard logical volume names (e.g. lvol1, lvo2, etc). In any event, you can manufacture your own mapfile. A standard set of three logical volumes would look like this:

1 lvol1
2 lvol2
3 lvol3

Regards!

...JRF...

[Helen French]

Thanks James, that was really a nice one !

Shiju

[Helen French]

Hi All,

Just thought of updating:

I did this and I could mount the 10.20 old HDD on the 11.0 system. Clay's suggestion was excellent ! steps:

1) Removed the mirror with lvreduce (-m 0)
2) Reduced the VG for making the HDD free for installation.
3) Checked 'lvlnboot -v' and found fine.
4) Did vgexport.
4) Tested starting the system with only one HDD (10.20, before installation)
5) Installed OS
6) Did 'vgimport' of old root HDD
7) Created /oldroot and I could read the data.

Thanks for all the inputs again !
Shiju