| PRIMECLUSTER Global Disk Services Configuration and Administration Guide 4.1 (Solaris(TM) Operating System) |
|
Contents
|
| Chapter 6 Backing Up and Restoring | > 6.2 Backing Up and Restoring a System Disk through an Alternative Boot Environment |
4) Parting the proxy groups
Once synchronization copying is completed, the master group and the proxy group become synchronized. Snapshots of a master group can be collected in a proxy group by parting the synchronized master group and proxy group.
4-1) Secure consistency of the file systems.
To secure consistency of snapshot file systems, restrain update of the file systems. However, file systems such as /, /usr, and /var are necessary for the system to operate, they cannot be unmounted during system operation. You can follow the procedure as below in order to reduce write occurrences to system disks and write occurrences to system disks that are not updated yet.
Boot the system in single user mode. (This can be skipped.)
Exit all active application programs writing in the system disks. (This can be skipped.)
Execute the sync(1M) command to write file system data updated in memory but not yet written to the disks.
The system may hang up if a / file system is locked not to be written in with the lockfs(1M) command. In addition, GDS and GDS Snapshot commands hang up if a /var file system is locked not to be written in. Therefore, / and /var should not be applied the write lock.
Even if all the steps a), b), and c) are enforced, it is impossible to completely restrain update on the file system. As a result, inconsistency similar to that after a system panic might occur in a snapshot file system.
If a), b), and c) are all enforced, a snapshot file system will be similar to a file system after a panic occurs in single user mode.
If only c) is enforced skipping a) and b), a snapshot file system will be similar to a file system after a panic occurs during the system operation.
In any of these situations, a file system may have inconsistency, and the file system should be checked for consistency and repaired as described in step 5-2).
4-2) Part the proxy groups.
|
# sdxproxy Part -c System -p Proxy1,Proxy2 |
4-3) When the system was booted in single user mode in a) of step 4-1), reboot it in multi-user mode.
4-4) When application programs were exited in b) of step 4-1), launch the application programs.
5) Configuring an alternative boot environment
Make booting available through the proxy volumes in preparation for an error due to a failed system disk or damaged data.
5-1) Set the access mode attribute of the proxy volumes to rw (read and write).
If the access mode attribute of proxy volumes created in the proxy group is ro (read only), it must be changed to rw (read and write). The access mode attribute can be viewed in the MODE field output by the sdxinfo -V -e long command. If the access mode attribute is already set to rw (read and write), executing the following commands is not necessary.
|
# sdxvolume -F -c System -v Proot,Pusr,Phome,Pswap,Pvar,Popt |
5-2) Verify and repair the file systems on the proxy volumes.
There may be inconsistency in file systems on proxy volumes, and so verify and repair them using the fsck(1M) command.
|
# fsck -y /dev/sfdsk/System/rdsk/Proot |
5-3) Configure the alternative boot environment.
|
# sdxproxy Root -c System -p Proxy1,Proxy2 |
Once the alternative boot environment is configured, the following message is output.
SDX:sdxproxy: INFO: completed definitions of alternative boot environment:
current-boot-device=/pci@1f,4000/scsi@3/disk@0,0:a pci@1f,4000/scsi@3/disk@1,0:a
alternative-boot-device=/pci@1f,4000/scsi@3/disk@2,0:a /pci@1f,4000/scsi@3/disk@3,0:a
Be sure to keep a copy of the output boot device names in the current boot environment (current-boot-device value) and in the alternative boot environment (alternative-boot-device value).
5-4) Stop the proxy volumes.
To protect data in the alternative boot environment from illegal write access, the proxy volumes should be inactivated.
|
# sdxvolume -F -c System -v Proot,Pusr,Phome,Pswap,Pvar,Popt |
6) Verifying the alternative boot environment. (This can be skipped.)
Confirm that the system can be booted in the alternative boot environment.
6-1) Boot the system through the alternative boot environment.
Execute the boot command in the OpenBoot environment. For the boot command, you can specify one of the boot devices in the alternative boot environment output in the message as shown in step 5-3).
|
# shutdown -y -g0 -i0 |
The boot command may fail as below if the number of the boot device names in the alternative boot environment output in step 5-3) exceeds the number of boot devices in the alternative boot environment.
|
ok boot /pci@1f,4000/scsi@3/disk@2,0:a Can't open boot device ok |
If this happens, you should specify another boot device name in the alternative boot environment output in step 5-3) and try the boot command again.
6-2) Confirm that it was booted normally.
Using the mount(1M) command or the sdxinfo command, make sure that it was booted normally in the alternative boot environment and that GDS objects do not contain errors. Additionally, according to need, you should confirm that file system contents in the alternative boot environment are correct and that applications can normally run.
6-3) Return to the original boot environment.
Execute the boot command in the OpenBoot environment. For the boot command, you can specify one of the boot devices in the current boot environment output in the message as shown in step 5-3).
|
# shutdown -y -g0 -i0 |
The boot command may fail as below if the number of the boot device names in the current boot environment output in step 5-3) exceeds the number of boot devices in the current boot environment.
|
ok boot /pci@1f,4000/scsi@3/disk@0,0:a Can't open boot device ok |
If this happens, you should specify another boot device name in the current boot environment output in step 5-3) and try the boot command again.
6-4) Stop the proxy volumes.
To protect data in the alternative boot environment from illegal write access, the proxy volumes should be inactivated.
|
# sdxvolume -F -c System -v Proot,Pusr,Phome,Pswap,Pvar,Popt |
7) Rejoining the proxy groups
To back up the system disks again, copy contents in the system disks to the backup disks again by rejoining a group of the backup disks (proxy group) to a group of the system disks (master group).
Copying by rejoining is finished quickly since only the updated blocks in the master and the proxy are copied through the just resynchronization mechanism (JRM). However, if the system is rebooted after the proxy is parted, the JRM is disabled and the entire volumes will be copied when the proxy is rejoined. Therefore, copying of the entire volumes is conducted instead of just resynchronization copying when the proxy groups are rejoined in step 7-1) if the system is rebooted after step 4-3) or step 6).
7-1) Rejoin the proxy groups.
|
# sdxproxy Rejoin -c System -p Proxy1,Proxy2 |
7-2) Confirm that synchronization copying is complete.
|
# sdxinfo -S -c System OBJ CLASS GROUP DISK VOLUME STATUS ------ ------- ------- ------- ------- -------- slice System Group1 Root1 root ACTIVE slice System Group1 Root2 root ACTIVE slice System Group1 Root1 usr ACTIVE slice System Group1 Root2 usr ACTIVE slice System Group1 Root1 home ACTIVE slice System Group1 Root2 home ACTIVE slice System Group2 Var1 swap ACTIVE slice System Group2 Var2 swap ACTIVE slice System Group2 Var1 var ACTIVE slice System Group2 Var2 var ACTIVE slice System Group2 Var1 opt ACTIVE slice System Group2 Var2 opt ACTIVE slice System Proxy1 Proot1 Proot STOP slice System Proxy1 Proot2 Proot STOP slice System Proxy1 Proot1 Pusr STOP slice System Proxy1 Proot2 Pusr STOP slice System Proxy1 Proot1 Phome COPY slice System Proxy1 Proot2 Phome COPY slice System Proxy2 Pvar1 Pswap STOP slice System Proxy2 Pvar2 Pswap STOP slice System Proxy2 Pvar1 Pvar COPY slice System Proxy2 Pvar2 Pvar COPY slice System Proxy2 Pvar1 Popt COPY slice System Proxy2 Pvar2 Popt COPY |
If synchronization copying is in process, COPY is displayed in the STATUS field for slices of the copy destination proxy group. If the STATUS of every slice in the proxy group is STOP, the synchronization copying is completed.
7-3) Part the proxy groups, configure the alternative boot environment, and confirm that the alternative boot environment is valid following the step from 4) to 6).
|
Contents
|