The Advanced Copy function of ETERNUS Disk storage system can link with VSS to implement a high-speed online backup of the Exchange server databases.
The backup data of an Exchange server database includes the backups of the following files that constitute the Exchange server database:
EDB file and STM file (database files)
Exchange Server 2003:
The paired EDB file and STM file constitutes a database. Both files exist in each information store.
Exchange Server 2007:
The database is comprised of only an EDB file (there is no STM file). Each information store contains one EDB file.
LOG file (the transaction log file)
The LOG file contains a transaction log. At least one LOG file exists in each storage group.
CHK file (the checkpoint file)
The checkpoint file points to the latest transaction in the transaction log that has been committed to the database. One checkpoint file exists in each storage group.
Online backup
A linkage with VSS enables the online backup of the Exchange server database.
Backup is performed in units of storage groups. Because backup processing is performed without stopping the messaging service, store access is enabled even during backup processing.
Because the backup data testing (ESEUTIL) and log deletion are executed as part of the online backup processing, these types of operations need not be executed after backup processing.
Backup using Advanced Copy (OPC/EC, REC or QuickOPC)
Backup can be created instantly and without placing a burden on the Exchange server, using Advanced Copy functions (such as OPC/EC, REC or QuickOPC).
Advanced copies are executed by the ETERNUS hardware provider. (*1)
Storage group configuration files (ie, those with extensions *.edb, *.stm, *.log or *.chk) are copied to the backup volume.
*1: Only the hardware provider for ETERNUS bundled to the AdvancedCopy Manager package for Windows Server 2003 is used in this function. The provider of other companies and ETERNUS VSS Hardware Provider cannot be used.
Note
REC is executed in the following operational modes for this function:
Transfer mode : Synchronous
Split mode : Automatic Split
Recovery mode : Automatic Recovery
For Exchange Server 2007, backup using EC/REC is not supported.
Backup to the backup server
The transport function of VSS shadow copy can be used to make a backup (a shadow copy) on the disk connected to the backup server. The function thus enables a backup to tape to be created without placing any load on the Exchange server.
Figure 8.1 Exchange server database backup processing image
Server | Component | Description |
|---|---|---|
Exchange server | Exchange Writer | Exchange writer |
ACM Requester | The AdvancedCopy Manager Exchange requester that provides backup and restore functions for Exchange. | |
ETERNUS Provider | ETERNUS hardware provider that offers a shadow copy creation function using Advanced Copy functions (such as OPC/EC, REC, or QuickOPC). | |
Backup server | ESEUTIL | Exchange server database consistency check and recovery utility. The ACM Requester uses this component to check backup data for consistency. |
ACM Requester | Exchange requester provided by AdvancedCopy Manager. This component manages (e.g., with a status check and deletion) the shadow copy according to instructions from the ACM Requester on the Exchange server. | |
ETERNUS Provider | ETERNUS hardware provider, which manages the copy destination disk (LUN). |
The Advanced Copy function of the ETERNUS Disk storage system can link with VSS to restore the Exchange server databases from the online backup data.
Restoration from online backup data
A linkage with VSS enables restoration from the online backup data.
As with a backup, restoration is performed in units of storage groups. All databases (ie, stores) are dismounted during restoration processing.
Two restoration modes are supported: roll-forward restoration (which is restoration to the latest point) and point-in-time restoration (which is restoration to the backup point).
When the online backup data is stored on tape, it must be restored in advance to the backup disk.
Note
Exchange Server 2007 supports a function that allows restoration to a different location than the original path, but AdvancedCopy Manager does not support this function. Therefore, the original disk is the only restore destination that can be selected under AdvancedCopy Manager.
High-speed restoration by OPC/EC/REC
Advanced Copy (e.g., OPC) can also be used for restoration to resume a job operation quickly without placing any load on the Exchange server.
OPC is executed by a conventional AdvancedCopy Manager function (e.g., swsrpmake (Replication creation command)).
Because log application and mounting are enabled soon after the execution of OPC logical copying, live operations can be restarted quickly without waiting for the completion of OPC physical copying.
When you perform restoration by EC or REC, the time between stopping and restarting live operations becomes longer than that in the case of using OPC, because you need to wait until all the data on the disk is copied. For this reason, if it is possible to use OPC, we recommend that you perform restoration by OPC.
The suspension of EC or REC is executed by a conventional AdvancedCopy Manager function (e.g., the replication creation command).
Log application and mounting are enabled soon after suspending EC or REC.
Figure 8.2 Exchange server database restoration processing image
*1: With VSS, the requester restores the necessary files without using a hardware provider for file copying in the restoration processing.
The requester performs restorations using existing functions (swsrpstartsync and swsrpmake).
Figure 8.3 Snapshot restoration (restoration by OPC)
Figure 8.4 Synchronous restoration (restoration by EC/REC)
In the point-in-time restoration mode, the Exchange server database and log file are restored so that the database is restored to the state it was in when it was backed up. Data created after the backup was created is not restored.
In the roll-forward restoration mode, the previous backup data and currently remaining transaction log are used to restore the database to the latest state. This mode can be used when the log file is not damaged, even though the database is damaged. It cannot be used when both the database and log file are damaged.
