1. Support
  2. Knowledge base
  3. 100022142

Downgrade diskgroup version using CBR data

Article: 100022142
Last Published: 2019-04-03
Ratings: 0 0
Product(s): InfoScale & Storage Foundation

Problem

Downgrade diskgroup version using CBR data

Error Message

VxVM vxdg ERROR V-5-1-587 Disk group dwgdg: import failed: Disk group has no valid configuration copies

Solution

There are situations that a Veritas Volume Manager (VxVM) disk group version needs to be downgraded, in order to import the disk group on a server running an older version of VxVM.
 
With current and past VxVM releases, there is not a single command available to downgrade the diskgroup version.
 
The most commonly used method to downgrade the diskgroup version is to "rebuild" the diskgroup. 
 
This article introduces another way to downgrade the disk group version using VxVM cbr (cbr stands for configuration backup restore) data and utility vxconfigrestore.
 
A disk group called dwddg is used as an example below in this document.
 
In the example, the VxVM version was upgraded from 4.1 to 5.0.  The disk group version was upgraded to 140 from 120 after completing VxVM upgrade..
 
Then user realized that the disk group version needs to be downgraded back to120.
 
When tried to import the disk group on the server running VxVM 4.1, received the error below.
 
# vxdg import dwddg
VxVM vxdg ERROR V-5-1-587 Disk group dwddg: import failed: Disk group has no valid configuration copies
 
Attempt to Import the diskgroup with -Cf options also failed with the same error
 
# vxdg -Cf import dwddg
VxVM vxdg ERROR V-5-1-587 Disk group dwddg: import failed: Disk group has no valid configuration copies
 
Startingfrom VxVM 3.5MP4, a new feature (called cbr) is introduced in VxVM.  This new feature not only backups up VxVM configuration, it also enables user to use the cbr data backed up (in /etc/vx/cbr/bk directory) to restore the VxVM configuration.
 
The procedures below show how the diskgroup version of dwddg is downgraded from 140 to 120..
 
1. check and make sure that the server is running VxVM with default diskgroup version 120(VxVM 4.1).
#modinfo |grep vx
 
2. check and make sure that VxVM can access all the disks for the disk group by running the two commands below
# vxdisk -o alldgs list |grep dwddg
c5t14d0s2    auto:sliced    -            (dwddg)      online
c5t14d22s2  auto:sliced    -            (dwddg)      online
 
and
 
#cat/etc/vx/cbr/bk/dwddg.1189258592.64.hd7d01h0/1189258592.64.hd7d01h0.cfgrec |vxprint -D - -ht | grep dm
 
dmhdsdwd01     c5t14d0s2    auto    7423     71162880 -
dmhdsdwd02     c5t14d22s2   auto     7423    71162880 -
 
It is important that the first command output shows the same number of the disks as the second command output, in this example 2.
 
3. run thecommand below to rebuild the disk group configuration with version 120
#/usr/lib/vxvm/bin/vxconfigrestore -p dwddg      
Diskgroup dwddg configuration restoration started ......
 
dwddg'sdiskgroup configuration is restored (in precommit state).
Diskgroup can be accessed in read only and can be examined using
vxprint in this state.
 
Run:
 vxconfigrestore-c dwddg ==> to commit the restoration.
 vxconfigrestore-d dwddg ==> to abort the restoration.
 
4. check the disk group configuration restored:
# vxprint-htg dwddg
DGNAME         NCONFIG      NLOG    MINORS   GROUP-ID
STNAME         STATE        DM_CNT  SPARE_CNT         APPVOL_CNT
... snip...
DCNAME         PARENTVOL    LOGVOL
SPNAME         SNAPVOL      DCO
 
dgdwddg        default      default  119000  1189258592.64.hd7d01h0
 
dmhdsdwd01     c5t14d0s2    auto    7423     71162880 -
dmhdsdwd02     c5t14d22s2   auto     7423    71162880 -
 
v  vloracle_102-            ENABLED  ACTIVE  8388608  SELECT    -        fsgen
plvloracle_102-01 vloracle_102 ENABLED ACTIVE8388608  CONCAT    -        RW
sdhdsdwd02-01  vloracle_102-01 hdsdwd02 0    8388608  0         c5t14d22 ENA
 
v  vlstage      -            ENABLED  ACTIVE  14680064 SELECT    -        fsgen
plvlstage-01   vlstage      ENABLED  ACTIVE  14680064 CONCAT    -        RW
sdhdsdwd01-01  vlstage-01   hdsdwd010        14680064 0        c5t14d0  ENA
 
v  vol_oracle  -            ENABLED  ACTIVE   10207232SELECT    -        fsgen
plvol_oracle-01 vol_oracle  ENABLED  ACTIVE   10207232CONCAT    -        RW
sdhdsdwd01-06  vol_oracle-01 hdsdwd01 60817408 102072320        c5t14d0  ENA
 
v  voldwdasdev  -            ENABLED  ACTIVE  12582912 SELECT    -        fsgen
plvoldwdasdev-01 voldwdasdev ENABLED ACTIVE   12582912CONCAT    -        RW
sdhdsdwd01-05  voldwdasdev-01 hdsdwd01 48234496 125829120       c5t14d0  ENA
 
v  voldwdasprd  -            ENABLED  ACTIVE  12582912 SELECT    -        fsgen
plvoldwdasprd-01 voldwdasprd ENABLED ACTIVE   12582912CONCAT    -        RW
sdhdsdwd01-02  voldwdasprd-01 hdsdwd01 14680064 125829120       c5t14d0  ENA
 
v  voldwdastst  -            ENABLED  ACTIVE  16777216 SELECT    -        fsgen
plvoldwdastst-01 voldwdastst ENABLED ACTIVE   16777216CONCAT    -        RW
sdhdsdwd01-03  voldwdastst-01 hdsdwd01 27262976 167772160       c5t14d0  ENA
 
v  voldwdrepdt  -            ENABLED  ACTIVE  4194304  SELECT    -        fsgen
plvoldwdrepdt-01 voldwdrepdt ENABLED ACTIVE  4194304  CONCAT    -        RW
sdhdsdwd01-04  voldwdrepdt-01 hdsdwd01 44040192 41943040        c5t14d0  ENA
 
5. check the disk group version before committing.  
# vxdg list dwddg |grep -i version
version:  120
 
6. commit the (downgraded) configuration restored
# vxconfigrestore -c dwddg
Committing configuration restoration for diskgroup dwddg ....
 
dwddg's diskgroup configuration restoration is committed.
 
The diskgroup can now be deported and imported normal with disk group version downgraded to 120.
 
A successful diskgroup downgrade is based on the following two:
1. diskgroup version in cbr data is correct
2. VxVM version - the default diskgroup version must be the diskgroup version to be downgraded to.
 
The default diskgroup versions for each VxVM versions are:
 
VxVMVersion                        Disk Group Layout Version
3.5                                          90
4.0                                          110
4.1                                          120
5.0                                          140
 
 
 

 

Was this content helpful?

Article Languages