Cleanly break SVM root mirror before some tests

Cleanly break SVM root mirror before some tests

Post by Alex0 » Sun, 09 May 2004 03:45:49



Hi,

I have a spare V210 (2 disks) that I want to use to do some tests for
some application.

To do so, I wanted to break my mirror, and then reinstall S9 on one of
the disk and do my tests (leaving the other disk intact).

And then when my tests will be done, simply boot off the original
disk, and remirror the whole thing, overwriting my test S9 install.

What is the best way to achieve this ? Detaching the slices on the 2nd
disk ? Offlining the mirror ? Complete tear down of SVM config ?

Thanks,

Alex...

 
 
 

Cleanly break SVM root mirror before some tests

Post by Ian » Sun, 09 May 2004 13:37:30



> Hi,

> I have a spare V210 (2 disks) that I want to use to do some tests for
> some application.

> To do so, I wanted to break my mirror, and then reinstall S9 on one of
> the disk and do my tests (leaving the other disk intact).

> And then when my tests will be done, simply boot off the original
> disk, and remirror the whole thing, overwriting my test S9 install.

> What is the best way to achieve this ? Detaching the slices on the 2nd
> disk ? Offlining the mirror ? Complete tear down of SVM config ?

Detaching the slices form the second disk will work - one way mirrors
are ok, but take care when you install on it to preserve the slice with
the metadadbs, otherwise you will have problems booting of the original
drive.

Make sure the drives are both bootable.  Detach the slices and do a test
boot before the install.

Cheers,

Ian

 
 
 

Cleanly break SVM root mirror before some tests

Post by Shivakanth Mundr » Sun, 09 May 2004 23:47:51




>> Hi,
>> I have a spare V210 (2 disks) that I want to use to do some tests for
>> some application.

>> To do so, I wanted to break my mirror, and then reinstall S9 on one of
>> the disk and do my tests (leaving the other disk intact).

>> And then when my tests will be done, simply boot off the original
>> disk, and remirror the whole thing, overwriting my test S9 install.

>> What is the best way to achieve this ? Detaching the slices on the 2nd
>> disk ? Offlining the mirror ? Complete tear down of SVM config ?

> Detaching the slices form the second disk will work - one way mirrors
> are ok, but take care when you install on it to preserve the slice with
> the metadadbs, otherwise you will have problems booting of the original
> drive.

> Make sure the drives are both bootable.  Detach the slices and do a test
> boot before the install.

> Cheers,

> Ian

It's a best/general practice to set up metadbs on both disks. Detaching
the mirrors should work. Make sure that /etc/init.d/lvm.sync has the
metasync -r line commented out so that the mirror resync wouldnt start
across reboots. You can chose to use Liveupgrade 2.0 while you have the
system up and running. Live upgrade 2.0 Guide tells how to upgrade when
you have boot disks mirrored with SVM or encapsulated with VXVM.

http://www.unixway.com/vm/disksuite/index.html has some good info on SVM.

Shivakanth.

 
 
 

1. testing Disk Mirroring with SVM

I did mirror my bootdisk and made entries for boot-device so that the
system can boot from rootmirror if rootdisk is unavailable/dead.

I tried removing my rootdisk and reboot the machine only to find out
that metadb are stale(system went to Single  user mode) and metadb -i
showed unknown for block count for the removed HDD. (c1t1d0s6)

# metadb -i
         flags           first blk       block count
      a m  p  luo        16              8192            /dev/dsk/c1t1d0s6
      a    p  luo        8208            8192            /dev/dsk/c1t1d0s6
      a    p  luo        16400           8192            /dev/dsk/c1t1d0s6
      a    p  luo        16              8192            /dev/dsk/c1t0d0s6
      a    p  luo        8208            8192            /dev/dsk/c1t0d0s6
      a    p  luo        16400           8192            /dev/dsk/c1t0d0s6

So It appears that I would need more than half of the copies of db's to
be available to have the system booted from rootmirror when rootdisk is
unavailable. Also, The master copy of db lies on rootdisk slice.

Did I miss something while I set up this mirror?

Everything is fine When I boot from rootmirror with rootdisk in place.

Can some one tell me how to test whether the system will boot from
rootmirror when rootdisk is unavailable?

Thanks,
Shivakanth

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