Can it restore an entire system with MC/SG & MirrorDIsk/UX?

[Gino Castoldi_2]

Hi,

HPUX 11.11 MC/SG 11.15 (2 node) MirrorDisk/UX
(2 way mirror), VG=vg00, vgshare.

We have two servers in a cluster that runs the
OVO/Oracle application. The system boot disk is mirrored. We have run Ignite backups
on both servers. One for VG=vg00 only and another Ignite backup for VG=vg00, vgshare.

If we needed to restore the system disk and/or
the entire system (VG=vg00, vgshare) will Ignite-UX be able to do the job?

10 points to any good ideas or answers.
TIA, Gino

[Marco Santerre · Accepted solution]

Short answer.. yes. Naturally, if you were restoring onto another system that is completely different than the one you are currently using, without your vgshare you wouldn't be able to run your applications, but yes Ignite will restore your VG00 and/or vgshare if need be.

Though I tend to agree with most recommendations that you should keep Ignite backups to VG00 only. You should backup your vgshare with another method, like Omniback or fbackup.

[Cesare Salvioni]

Ciao
make_tape_recovery is the usual solution to restore system from scratch
Usually i use make_tape_recovery -A to make a bootable tape that rebuild the vg00, while data on other vg are regularly backed up with other backup system.
Just remember two important facts about make_tape_recovery
1. it doesn't restore the LV mirror, this must be done by hand after the restoring process with lvextend -m 1 for each lv and mkboot -b , it is possible also to configure script made by make_tape_recovery to rebuild the mirror copy automatically but it's not so simple as doing by hand
2. make_tape_recovery does NOT backup files greater than 2 Gbytes, if pax is well patched it should avoid these files, otherway make_tape_recovery will copy the files to the tape but restoring will fail completly: AVOID FILES GREATER THAN 2G (this is why i always use make_tape_recovey only for vg00, which holds only OS)
3. make_tape_recovery writes two parts on the tape, first one is a bootable segment, second one is a tar. You can reach the second one just reading the tape using /dev/rmt/0mn. First time it fails, second time it read the tar file, so you can extract one or more files from tap recovery

In my opinion and experience make_tape_recovery is a good tool, i'm used to isolate OS and products on VG00 and make a fresh tape every time i change OS configuration or install new important products.

Hope this helps
ciao

[Bernhard Mueller]

Gino,

I take it you have your OVO running as an MC/SG package and hence it should remain up and running, right?

As long as the app/database is running there is no use in including the shared vg into the recovery image.

Instead you should backup your vgshare using conventional backup means. Else the recovery would not only take much longer but more important the database would not be in a consistent state.

The way to to it is
make_tape_recovery -I -x inc_entire=vg00 -a /dev/rmt/0mn

Using such tape will restore the system (except boot disk mirroring), and vgimport all the vgs that were active when you created the tape.

However, you will also have to run a vgchange -c y vgshare after it is imported.

If you cut the tape on the node where the package (vgshare) was not active then vgshare will not be imported, you will have to do this manually.

If you need to restore anything in vgshare, use a faster backup than tar (which ignite uses).

Regards,
Bernhard

P.S. If you purposefully want to *clone* this entire system onto *other*, similar HW (including other disks for vgshare). You could halt your package, vgchange -a e vgshare,
mount all filesystems like the package would mount them and then run
make_tape_recovery -I -x inc_entire=vg00 -x inc_entire=vgshare -a /dev/rmt/0mn.

[Jeff Schussele]

Hi Gino,

Well...Yes and no.

Yes - it can restore an entire system.
But, no, it cannot restore mirror disks.
You'd have to remirror all mirrored LVs.

Rgds,
Jeff

[Bernhard Mueller]

Gino, one more warning:

if you take the cloning route for duplicating instead of recovery of the actual cluster, you should be aware that there is more to it regarding MC/SG setup, with nodenames, ip addresses etc.

though you can change hostname and ip address upon recovery, you cannot change the MC/SG configuration through Ignite-UX.

Regards,
Bernhard

[Michael Duthie]

All the above correct but although Ignite does not mirror the root disk it will add a second disk into the root vg but it does not use the -B option on pvcreate, so you have to remove it, pvcreate -B and re-add before running the mkboot commands.

For cloning and rebuilting MCSG apart from importing the vgshare you will need to build a new cluster ascii file with cmquerycl -v -C cluster.ascii -n node1 -n node2. edit number of packages the cmcheck/applyconf. Job done.