PRIMECLUSTER Global Disk Services Configuration and Administration Guide 4.2 (Linux)
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Chapter 6 Backing Up and Restoring> 6.6 Backing Up and Restoring through an External Server> 6.6.1 Backing Up and Restoring a Logical Volume with No Replication

6.6.1.7 Restoring

9) Stopping the services

Exit all applications accessing application volume Volume1 on Node1 and Node2 in the primary domain.

When Volume1 is used as a file system, it should be unmounted.

 

10) Stopping the application volume

To write-lock application volume Volume1, inactivate Volume1 on Node1 and Node2 in the primary domain. Execute the following command on Node1 or Node2.

# sdxvolume -F -c Class1 -v Volume1 -e allnodes

 

11) Viewing the configuration and status of the application volume

On Node1 or Node2 in the primary domain, view the configuration and status of application volume Volume1 that is the restore target. Confirm that Volume1 is in the STOP status. If the volume status is invalid, repair it referencing to "Volume Status Abnormality"

# sdxinfo -c Class1
OBJ    NAME    TYPE     SCOPE       SPARE
------ ------- -------- ----------- -----
class  Class1  shared   Node1:Node2     0
OBJ    NAME    TYPE   CLASS   GROUP   DEVNAM  DEVBLKS  DEVCONNECT    STATUS
------ ------- ------ ------- ------- ------- -------- ------------- -------
disk   Disk1   stripe Class1  Group1  sda     8380800  Node1:Node2   ENABLE
disk   Disk2   stripe Class1  Group1  sdb     8380800  Node1:Node2   ENABLE
disk   Disk3   stripe Class1  Group1  sdc     8380800  Node1:Node2   ENABLE
disk   Disk4   stripe Class1  Group1  sdd     8380800  Node1:Node2   ENABLE
OBJ    NAME    CLASS   DISKS                     BLKS    FREEBLKS SPARE
----- ------- ------- -------------------------  -------- -------- -----
group  Group1  Class1  Disk1:Disk2:Disk3:Disk4   32964608 31850496     *
OBJ    NAME    CLASS   GROUP   SKIP JRM  1STBLK   LASTBLK   BLOCKS   STATUS
------ ------- ------- ------- ---- ---  -------- --------  -------- --------
volume *       Class1  Group1  *    *          0    65535      65536 PRIVATE
volume Volume1 Class1  Group1  *    *      65536  1114111    1048576 STOP
volume *       Class1  Group1  *    *    1114112 32964607   31850496 FREE
OBJ    CLASS   GROUP   DISK    VOLUME  STATUS
------ ------- ------- ------- ------- --------
slice  Class1  Group1  *       Volume1 STOP


If application volume Volume1 belongs to a stripe group, also pay attention to the stripe width.

# sdxinfo -G -c Class1 -o Group1 -e long
OBJ   NAME   CLASS  DISKS                    BLKS      FREEBLKS SPARE MASTER TYPE    WIDTH
----- ------ ------ ------------------------ --------- -------- ----- ------ ------  -----
group Group1 Class1 Disk1:Disk2:Disk3:Disk4  32964608  31850496 *     *     stripe  256

 

12) Creating a shadow volume for restore

On backup server Node3, create a volume for restore (shadow volume) in the same configuration as the application volume found in step 11). The following settings are necessary on backup server Node3. A shadow volume for restore and a shadow volume for backup are common. When it has already been created, simply change the access mode as described in step 12-4).


Application volume data may be damaged if data is written into a shadow volume in incorrect configuration. Be sure to confirm that the shadow volume configuration is correct in step 12-5).

12-1) Registering shadow disks

Register disks sda, sdb, sdc, and sdd with shadow class Class2, and name them Disk1, Disk2, Disk3, and Disk4 respectively.

# sdxshadowdisk -M -c Class2 -d sda=Disk1,sdb=Disk2,sdc=Disk3,sdd=Disk4


12-2) Creating a shadow group

Connect shadow disks Disk1, Disk2, Disk3, and Disk4 to stripe type shadow group Group1.

# sdxshadowdisk -C -c Class2 -g Group1 -d Disk1,Disk2,Disk3,Disk4 -a type=stripe,width=256


12-3) Creating a shadow volume

Create shadow volume Volume1 to Group1.

# sdxshadowvolume -M -c Class2 -g Group1 -v Volume1 -s 1048576


12-4) Setting the access mode of the shadow volume

Activate shadow volume Volume1 in the read and write access mode (rw).

# sdxshadowvolume -F -c Class2 -v Volume1
# sdxshadowvolume -N -c Class2 -v Volume1 -e mode=rw


12-5) Viewing the shadow volume configuration

Using the sdxinfo command, confirm that the group configuration and the volume configuration are correct based on group information in the DISKS field, volume information in the 1STBLK field and in the BLOCKS field and so on.

# sdxinfo -c Class2
OBJ    NAME    TYPE     SCOPE       SPARE
------ ------- -------- ----------- -----
class  Class2  local    Node3           0
OBJ    NAME    TYPE   CLASS   GROUP   DEVNAM  DEVBLKS  DEVCONNECT    STATUS
------ ------- ------ ------- ------- ------- -------- ------------- -------
disk   Disk1   stripe Class2  Group1  sda     8380800  Node3         ENABLE
disk   Disk2   stripe Class2  Group1  sdb     8380800  Node3         ENABLE
disk   Disk3   stripe Class2  Group1  sdc     8380800  Node3         ENABLE
disk   Disk4   stripe Class2  Group1  sdd     8380800  Node3         ENABLE
OBJ    NAME    CLASS   DISKS                     BLKS    FREEBLKS SPARE
------ ------- ------- ------------------------- -------- -------- -----
group  Group1  Class2  Disk1:Disk2:Disk3:Disk4   32964608 31850496     *
OBJ    NAME    CLASS   GROUP   SKIP JRM  1STBLK   LASTBLK   BLOCKS   STATUS
------ ------- ------- ------- ---- ---  -------- --------  -------- --------
volume *       Class2  Group1  *    *          0    65535      65536 PRIVATE
volume Volume1 Class2  Group1  *    *      65536  1114111    1048576 ACTIVE
volume *       Class2  Group1  *    *    1114112 32964607   31850496 FREE
OBJ    CLASS   GROUP   DISK    VOLUME  STATUS
------ ------- ------- ------- ------- --------
slice  Class2  Group1  *       Volume1 ACTIVE


For a stripe volume, see also the stripe width.

# sdxinfo -G -c Class2 -o Group1 -e long
OBJ    NAME    CLASS   DISKS               BLKS     FREEBLKS SPARE MASTER TYPE   WIDTH
------ ------- ------- ------------------- -------- -------- ----- ------ ------ -----
group  Group1  Class2  Disk1:Disk2:Disk3:Disk4 32964608 31850496 *   *    stripe  256

 

13) Restoring from tape

On backup server Node3, restore shadow volume data from tape to which it was backed up in step 6). In the following examples, restore data held in shadow volume Volume1 from a tape medium of tape device /dev/st0.


For details on the restore method, see the manuals of file systems to be restored and used commands.

In a GFS Shared File System
Restore through the method as described in step 13a).

13a) When restoring data with the dd(1) command

# dd if=/dev/st0 of=/dev/sfdsk/Class2/dsk/Volume1 bs=32768


13b) When restoring the ext3 file system with the tar(1) command

13b-1) Create the ext3 file system on Volume1.

# mkfs -t ext3 /dev/sfdsk/Class2/dsk/Volume1


13b-2) Mount the ext3 file system on shadow volume Volume1 on /mnt1, a temporary mount point.

# mkdir /mnt1
# mount -t ext3 /dev/sfdsk/Class2/dsk/Volume1 /mnt1


13b-3) Restore data held in the file system from tape.

# cd /mnt1
# tar xvf /dev/st0


13b-4) Unmount the file system mounted in step 13b-3).

# cd /
# umount /mnt1
# rmdir /mnt1

 

14) Removing the shadow volume

After the restore process is complete, remove the shadow volume to prevent improper access to it. The following procedure must be performed on backup server Node3.

14-1) Stopping the shadow volume

Stop shadow volume Volume1.

# sdxshadowvolume -F -c Class2 -v Volume1


14-2) Removing the shadow volume

Remove shadow volume Volume1.

# sdxshadowvolume -R -c Class2 -v Volume1


14-3) Removing the shadow group

Remove shadow group Group1.

# sdxshadowgroup -R -c Class2 -g Group1

14-4) Removing the shadow disks

Remove shadow disks Disk1, Disk2, Disk3, and Disk4.

# sdxshadowdisk -R -c Class2 -d Disk1
# sdxshadowdisk -R -c Class2 -d Disk2
# sdxshadowdisk -R -c Class2 -d Disk3
# sdxshadowdisk -R -c Class2 -d Disk4

 

15) Resuming the services

Resume the services in the primary domain. The following procedure must be performed on the node that runs the services.

15-1) Activating the application volume

Activate application volume Volume1.

# sdxvolume -N -c Class1 -v Volume1


15-2) Resuming the services

When the file system on application volume Volume1 was unmounted in step 9), mount it again.

Start the applications using Volume1.



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