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The SQL Server can make a Database Consistency Check of the database it's working with.
The Consistency Check searches for Database File Structure errors, but doesn't inspect integrity constraints defined for the Database Tables.
Consistency Error Types
There are two major groups of Consistency Errors:
•Errors that cause worse drive space utilization in the Database
Errors such as these only reduce the storage space efficiency of a drive and may occur each time the SQL Server is not correctly terminated.
•Damage to data stored in the Database.
Errors such as these mean that a part of the stored data is overwritten or inaccessible. They may occur when the computer running the SQL Server crashes when terminating a transaction.
Running a Database Consistency Check
After you perform a Backup/Archive operation, or if you experience hardware or operating System failure, you can run the DBCC CHECKDB query in Microsoft SQL Server Management Studio to verify that the Database is still consistent.
When and if the query completes successfully, you will get a status on the bottom of the Query dialog.
Verify the results report 0 Allocation errors and 0 Consistency errors.
•If both show 0, the Database is healthy and the Query can be closed.
•If errors are found, a recommendation of what minimum level of repair will be listed at the bottom of the Query dialog in the Message Summary.
Archive and Backup - System Overview
The EMS Archive/Backup System provides 4 main functions:
Archives older recorded EMS data, reducing the current database footprint, and stores this archived data so that it can be restored to a viewable state for reference in the future.
Backs up the current state of the EMS System so that EMS data and settings can be restored to the current position, should some kind of major System failure occur.
Restores an Archive to a viewable state, without affecting the current EMS System state.
Restores EMS from an existing Backup, overwriting the current System state.
The EMS Archive/Backup System is composed of:
•The EMSArchiveService service
•The HanwellEMSArchive database.
➢All Archive/Backup operations are executed by the EMSArchiveService service.
➢The EMSArchive Database contains Archive/Backup schedule information and Archive/Backup job results and is created when the EMSConfigUtility is used to create a new EMS Backup Database.
➢When upgrading from a version prior to EMS, the EMSArchive Database is created during the Upgrade process.
Archive and Backup functionality is accessed by:
|Note:||The EMSBackupArchiveTool can only be used to create Backups and Archives to an existing EMS Backup Database and to restore Archives.|
The EMSBackupArchiveTool CANNOT restore Backups or create a new EMS Backup Database to backup and archive information to.
The EMSConfig Utility
Users can schedule Archive jobs to run as a single instance or at a scheduled interval.
•Files output by an Archive job will have the Archive job name, plus the current date time formatted as:
e.g. Fred20131023153000.bak; thus ensuring that existing Archive data is not overwritten.
•Archives consist of an SQL backup and a zip file containing any uploaded EMS image files.
The Archive User is a special User that has access to all Menus, Sites and Grids in an archived database.
•Creating archives automatically adds the Archive User to the System.
•The default password for the Archive User is:
This can be changed, if required, by selecting editing the Archive User from the main System's Edit/View Users control.
The Archive Overlap defines the range of data maintained in the EMS Database after an Archive operation has archived all of the EMS Database's information.
•Data older than the start of the Archive Overlap period is deleted from the EMS Database after an Archive operation. See Figure 1366 below:
•If an Archive Overlap is not set for an Archive job, then no data is deleted from the EMS database.
|Example:||Say an Archive is taken at 23:30 on 31st December 2013 and an Archive Overlap is set for 3 months.|
After the Archive operation competes:
>> The Archive Database will contain a copy of all the data from the EMS Database as at 23:30 on 31st December 2013.
>> Data in the EMS database before 23:30 on 30th September 2013 will be deleted, leaving only data from 23:30 on 30th September 2013.
Archive Overlaps can be set as multiples of days, weeks, or months.
As with Archive jobs, Users can schedule Backup jobs to run as a single instance or at a scheduled interval.
•Backups running on a regular schedule can be set to overwrite any previous Backup from the same job.
➢Where the Overwrite flag is set for a job, output files will have the name of the Backup job, e.g. Fed.bak.
➢Where the Overwrite flag is not set, output files will have the Backup job name, plus the current date time formatted as:
e.g. Fred20131023153000.bak; thus ensuring that existing Backup data is not overwritten.
•Where the Overwrite flag is set for a job, the completed Backup Job will delete the Database Log Entry for any previously run Backup job of the same name and whose files are overwritten by the current Job, as the older backup files will no longer be available for restoration.
•Backups consist of a SQL backup and a zip file containing any uploaded EMS image files.
When enabled, scheduled intervals for both Archives and Backups can be set as multiples of days, weeks or months.
Restoring an Archive will create a new database on the SQL server with the name of the restored Archive file, e.g. Fred20131023153000.
|Note:||Restored Archives are only intended to provide a mechanism for viewing archive data; new data values WILL NOT be written to the databases restored from Archive files.|
•Archives can be restored using the either the EMSBackupArchiveTool or the EMSConfig Utility.
Backups are intended to provide a mechanism for recovering EMS data and settings after a System failure.
•Restoring a Backup will overwrite the current EMS Database and Image files with data from the Backup files.
The EMS Archive/Backup System is intended to augment, NOT replace, proper System backup and Disaster Recovery Plans and practices.
|Note:||System Administrators need be aware that Microsoft SQL servers generally write database backup files to the Local System Hard Drive and that the EMSArchiveService writes the Zipped image files to the Services Common Application Data Folder, on the Local System Hard Drive.|
Furthermore, the EMS Archive/Backup itself uses a database – HanwellEMSArchive – to hold details of Archive/Backup jobs on the SQL Server.
If a Backup is restored to an SQL Server on a new machine, passwords encrypted in the database for use by the EMS Data Service will be unrecoverable and will need to be re-entered into EMS.
•This will affect passwords entered for use with Email servers; EMS’s User passwords ARE NOT used by the Data Service and will work as before.