The following devices must not be backed up or replicated:
The device on which the system is stored
The device on which AdvancedCopy Manager has been installed
The device on which the management list of AdvancedCopy Manager resides
Data in Transaction Volume | Maintenance of Data Integrity | Operation |
|---|---|---|
File system | An AdvancedCopy Manager command unmounts the file system to maintain the integrity. | Refer to "Appendix A Pre-processing and Post-processing of Backup and Restoration" and "Appendix C Pre-processing and Post-processing of Replication". |
Other than the above | The data integrity must be maintained in operations. | Take appropriate action, such as stopping transactions during execution of backup or replication. |
Before starting either the backup or replication operation, fetch information of devices that are managed by all Managed Servers using Web Console. Refer to "3.4.4 Fetching Device Information on Managed Server" for the fetching procedure. The time taken to complete this operation is proportional to the total number of devices defined on the selected Managed Servers. If many devices are involved, perform this operation while the CPU or I/O load on the system is low.
As a guide, about 0.5 seconds are required per device (i.e., disk) when there is no load on the system.
All the devices are always in use while any of the following software is running. Therefore, before performing backup, restoration, or replication, perform the following steps:
When performing backup/restore operation and replication operation, to prevent software from accessing a device targeted for service, suspend the software or specify the device for services other than check or monitoring by the software. For the setting method, refer to the manuals for respective software.
There is an upper limit (maximum value) to the number of Advanced Copy sessions that can be simultaneously executed. For this reason, make an operational design so that Advanced Copies exceeding the maximum number of copy sessions cannot simultaneously be executed.
Also, when creating partitions in one Logical Unit (LU) and running Advanced Copy at the same time, be sure not to exceed the maximum number of copy sessions simultaneously executable per LU.
For the upper limit to the number of copy sessions simultaneously executable, refer to the ETERNUS Disk storage system manuals.
When the device has a multipath configuration, a path switch is not carried out automatically, even if one of the two paths is blocked.
When one of the two paths is blocked, perform the backup or replication again after taking the following steps:
Execute the following command on an available device to switch the path:
/usr/sbin/lspv hdisk*
Execute the backup or replication command again.
Before backup/restoration or replication of a volume that can be mounted from multiple servers, unmount and cancel any pending mount on the other servers.
For disks that need not be mounted from other servers, prevent multiple servers from detecting or accessing the same logical disk by setting up hardware, such as devices in the ETERNUS Disk storage system and Fibre Channel switches, accordingly.
For a copy operation targeted at a file system, unmount the relevant volume to prevent data access and maintain the data integrity.
If backup/restoration and replication are performed without unmounting the volume, an error occurs since a volume in use cannot be unmounted.
Note the following about processing where unmounting is enabled:
Another application is not using the volume. If another application is using it, suspend the application temporarily.
Users are not using the volume. If users are using it, prohibit them from using it temporarily.
Another volume is not mounted on the volume. If it is mounted, unmount it temporarily.
The volume is not shared with NFS sharing. If it is shared, unshare it temporarily.
Unmounting is required only during command execution. Normal operations can be resumed after command execution.
Copies can be made between different operating systems by using replication operations.
Use the following combinations to execute copy between different operating systems:
Copy Source | Copy Destination | |
|---|---|---|
Slices | Logical Unit (Disk) | |
slices | A | N/A |
Logical Unit (disk) | A | N/A |
(A=Available, N/A=Not Available)
When a copy is performed, the Logical Unit (disk) data is written in the replication destination volume (slice). If a copy is performed with a file system existing on the replication destination volume (slice), because a data overwrite can occur to the file system depending on the copy, not only will the data in the file system become inaccessible but the copied data will become inaccessible through the file system as well.
When replication occurs between servers, the -m option can be specified in the following commands in order to avoid communication processing to non-operating servers:
swsrpstartsync command
swsrpmake command
swsrpcancel command
When the -m option is specified, any one of the following conditions must apply in order to ensure that problems do not arise as a result of not performing volume pre-processing and post-processing at the non-operating server:
The non-operating server has been shut down.
Manual pre-processing and post-processing is performed for the volumes on the non-operating server.
The target volume is a RAW device (Oracle, etc., that does not need pre-processing and post-processing), rather than a file system.
When you execute the swsrpstartsync command with the -t option, volume lock fails with the swsrpmake command and the swsrp3607 message may be output.
If you execute the swsrpstartsync command with the -t option to perform independent pre-processing, check whether the pre-processing has properly been done.
If you determine that pre-processing and post-processing for replication destination volume is not needed and execute the swsrpstartsync command with the -t option, execute the swsrpmake command with the -t option.
The Advanced Copy processing is performed by the ETERNUS Disk storage system. Therefore, direct enquiries concerning copy processing performance to the support department for the ETERNUS Disk storage system.
When restart the server after executing backup or replication, the backup volume is disabled because its status changes from "active" to "defined". Furthermore, the backup volume may be newly detected by another device name. In this case, the backup management/replication management command becomes one of the following errors:
swst3603
swst3605
swst3606
swsrp3603
swsrp3605
swsrp3606
When this occurs, the newly detected device must be deleted and the backup volume that can no longer be detected must be recovered.
Follow the steps below:
(The examples below explain the cases where the transaction volume is described as vg02 created in hdisk2, the backup volume is described as vg04 created in hdisk4, and the newly detected device name is described as hdisk17.)
Unmount all volumes in the transaction volume.
# umount /mnt/vg02
Deactivate the volume group of the transaction volume.
# varyoffvg vg02
Check the disk status.
# lspv hdisk0 005f74da1705160e rootvg active hdisk1 005f74da6688a970 None hdisk2 005f74da8a1b6e2f vg02 active hdisk3 005f74da70e35fc7 vg03 active hdisk5 005f74da8af5069d None hdisk16 005f74da6fd209eb vg16 active hdisk17 005f74da8a1b6e2f vg02 active <- The backup volume detected with a new name.
Delete the disk definition newly detected.
# rmdev -l hdisk17 -d hdisk17 is deleted
Activate the volume group of the transaction volume.
# varyonvg vg02
Mount all the volumes in the transaction volume.
# mount /mnt/vg02 /dev/lv00 log is recreated
Status of the transaction volume is activated.
# mkdev -l hdisk4 hdisk4 can be used
Check if the backup volume can be activated for use.
# lspv hdisk0 005f74da1705160e rootvg active hdisk1 005f74da6688a970 None hdisk2 005f74da8a1b6e2f vg02 active hdisk3 005f74da70e35fc7 vg03 active hdisk4 005f74da8a2d04e0 vg04 hdisk5 005f74da8af5069d None hdisk16 005f74da6fd209eb vg16 active
If multiple commands that display the Advanced Copy status, such as the copy status display command and operation status display command, are executed simultaneously, the response speed from the storage device is reduced and may affect command executions and transactions.
For this reason, design the operation so that multiple commands cannot be executed at the same time.
