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How to break root disk Mirror in VxVM

Created: 08 Jun 2014 • Updated: 12 Jun 2014 | 7 comments
This issue has been solved. See solution.

Hi All

bash-3.00# vxprint -g rootdg -vh rootvol

v  rootvol      root         ENABLED  60821952 -        ACTIVE   -       -
pl rootvol-01   rootvol      ENABLED  60821952 -        ACTIVE   -       -
sd rootdg01-B0  rootvol-01   ENABLED  1        0        -        -       Block0
sd rootdg01-02  rootvol-01   ENABLED  60821951 1        -        -       -
pl rootvol-02   rootvol      ENABLED  60821952 -        ACTIVE   -       -
sd rootdg02-01  rootvol-02   ENABLED  60821952 0        -        -       -

bash-3.00# df -h /

Filesystem             size   used  avail capacity  Mounted on
                        29G    19G   9.4G    67%    /

From above configuration we see root file system is configured on volume rootvol which is a mirror. Now i'd like to break the mirror and keep the mirror copy for backout purpose as i will be upgrading on the actual root disk. I do not want to delete the plexes or the mirror copy.

Suppose in SVM, d0 is a mirror and d10 and d20 are its submirrors, we issue metadetach d0 d20 command to detach the submirror.

How do we accomplish the same in the above VxVM configuration ?

Plex rootvol-02 has only 1 subdisk rootdg02-01, whereas Plex rootvol-01 has 2 subdisks rootdg01-B0 and rootdg01-02.

What is the significance of having 2 subdisks for the plex rootvol-01 ? If the Plex rootvol-01 is a mirrored copy of another plex rootvol-02 then the size and number of subdisks in each plex should be the same or not ?



nvramrc=devalias vx-rootdg01 /pci@1f,700000/scsi@2/disk@0,0:a
devalias vx-rootdg02 /pci@1f,700000/scsi@2/disk@1,0:a

Once the root volume plex has been disassociated can we still use both the above listed device aliases to boot OS from ok prompt ?

ok> boot vx-rootdg01
ok> boot vx-rootdg02

Thank you everybody for your response as always. Response is highly appreciated.


Operating Systems:

Comments 7 CommentsJump to latest comment

Gaurav Sangamnerkar's picture

Hi Danish,

Here are you answers

1. A good technote that explains all the steps in order

Some more similar posts

2. If you carefully see the subdisk layout, one of subdisk is just 1 block to contain a boot block possibly which is nothing but block 0. Rest of question is answered in links above. Do visit the guide to understand the procedure of how to boot a system from alternate disks

3. The alias names are still on OBP & not modified with above process so yes, the alias names should still work.


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M.Danish's picture

Thanks Gaurav Bhai for your immediate response. Its always a pleasure to see your reply. :)

mikebounds's picture

If Gaurav's response answers your post, please mark as solution.


UK Symantec Consultant in VCS, GCO, SF, VVR, VxAT on Solaris, AIX, HP-ux, Linux & Windows

If this post has answered your question then please click on "Mark as solution" link below

M.Danish's picture

Sure Mike, Will mark as solution.

I have a little more doubt please...

If my OS is running on native SCSI disk like the one below.

bash-3.00# cat /etc/vfstab.prevm

#device         device          mount           FS      fsck    mount   mount
#to mount       to fsck         point           type    pass    at boot options

/dev/dsk/c1t0d0s0       /dev/rdsk/c1t0d0s0      /       ufs     1       no      -

In order to bring it under VxVM control and mirror it I should use vxencap, vxrootmir and vxmirror. Is this right? Do we have any Technote for Native OS disk encapsulation and mirroring process.

I also have this below doubt in the technote which refers to go back to mirror disk if upgrade (OR) patching fails

"Remove the partition having tag 14 and 15 from mirror disk using format completely. Do not just change tag type, zero out these partitions and labels before exiting from format."

Is vxbootsetup similar to installboot on native OS disk.

Thanks for your support as always.


Gaurav Sangamnerkar's picture

Hi Danish,

1. Best is you use vxdiskadm menu, it is a menu based guided program that will help you to complete encapsulation

2. What exactly is your doubt? Step is saying to delete public and private partition from partition table

3. The vxbootsetup utility configures physical disks so that they can be used to boot the system. Before vxbootsetup is called to configure a disk, mirrors of the root, swap, /usr and /var volumes (if they exist) should be created on the disk. These mirrors should be restricted mirrors of the volume. The vxbootsetup utility configures a disk by writing a boot track at the beginning of the disk and by creating physical disk partitions in the UNIX VTOC that match the mirrors of the root, swap, /usr and /var.


PS: If you are happy with the answer provided, please mark the post as solution. You can do so by clicking link "Mark as Solution" below the answer provided.

M.Danish's picture

Hi Gaurav Bhai/Others,

Here is my actual Requirement 

OS=Solaris 10 3/05 (Initial Release), SFHA=4.1 (VxVM,VxFS,VCS), Env=Sparc, 
Active-Passive Cluster (2 Nodes).

Planning to
1) Upgrade OS from 10 3/05 to 10 1/13 Update 11
2) Upgrade SFHA from 4.1 to 5.1SP1RP4 (OR) maybe 6.0.

My Plan

1) Break root mirror and perform Sanitary reboot using both disks (rootdisk and rootmirror)

2) Install on the rootdisk the Liveupgrade Patches & Packages ( Outlined in Oracle Doc ID 1004881.1)

3) On rootdisk , issue lucreate command to create a new boot environment on rootmirror (now dis-associated from rootdg) and Upgrade to Solaris 10 1/13 Update 11 with LiveUpgrade using ISO Image.

4) Once upgraded to Sol 10 Update 11, Upgrade SFHA from 4.1 ---> 4.1MP2 ---> 5.1SP1 ---> 5.1SP1RP4 (OR) 6.0

This is my actual requirement so was asking all the above above and below questions.

What is the functionality of the file /etc/vx/reconfig.d/state.d/install-db ? what purpose does it server ?

Thanks again,

Gaurav Sangamnerkar's picture

I would recommend to go for 6.1 out atleast 6.0

Install-db file will disable vxvm to start automatically during server boot


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