Computer data is at the center of your business. Today, your daily life depends on the availability of your digital information, whether in the form of applications or files. Failure to secure this critical data for your business can be a real management error in the event of a problem.
In addition to your user data, it may be interesting or even important to back up the entire environment of your server and workstations. This solution is called disk image backup, which can be represented as a “photocopy” of your equipment’s hard drive; in the event of a breakdown, the time required to return to working condition and in working conditions is significantly reduced, since to restore the disk image it is enough to find the whole working environment instead of reinstalling everything manually (system, programs, data, peripherals). This type of backup, like the main backup, can be done on removable media or not.
Importance of reboot. For backup and recovery operations to be fast and efficient, some organizational rules must be followed:
– It is necessary to consider the working hours of users so that the backup does not interfere with their work. So that their work does not interfere with conservation! For example, an editable table or catalog directory referenced by a library cannot be copied because they are used. – The frequency of updating data and metadata must be taken into account in order to determine the frequency of backups. – You must accurately date the backups and report the exact version of SAS (with the service pack) used during this backup. Here is an example destination for directories hosting quarterly backups. – You must save information related to the original architecture.
You must copy the entire backup to the source directories. The data backup date must be the same as the metadata to ensure consistency. You can control the physical structure of tables from ETL Studio using the “View Statistics” function. This allows you to see the physical structure of the table (this is the result of the CONTENTS procedure for the selected table). To date, there is no tool to highlight the differences between the definition in metadata and the actual structure of the table: this verification step must be performed manually. One could also write a program comparing metadata (obtained using XML queries) and a physical table (obtained using the CONTENTS procedure).
If you notice the difference between the variables defined in the metadata and the physical tables, then you can use the “Update metadata” function. This allows you to modify metadata according to the physical structure of the table. For example, if a variable does not exist in the physical table, it is removed from the table definition. On the inventory or user tab, right-click the table and select “Update Metadata from the Table” (or “Update Metadata”). The change will take effect immediately.
Scenario: by mistake, the user deleted the task. He wants this work to be restored. Actions: – If the task was exported to an XML file, you need to import this XML file. In ETL, select Tools Import Job and Merge Wizard. – If the task has been deployed for planning, there is a .SAS program. Then you can create a new job that will contain the “User Code” process pointing to this program. – If the metadata has not changed since the last backup, you can consider restoring the metadata. But it is important to make sure that the information will not be lost: this may affect other tasks or the attributes of the table can be changed with this return.
Scenario: Your metadata server references a library that contains multiple tables. Incidentally, the table is physically deleted. Actions: Just repair the table. It does not matter for metadata. Indeed, it refers to the attributes of tables without checking their existence, so a table can be used (for example, creating a task), even if it no longer exists physically. On the other hand, executing a link to a program or, for example, viewing data, will naturally show an error. If the table structure has changed since this backup was created, and the metadata refers to the new structure, you can update the metadata. To do this, on the “Inventory” or “User” tab, right-click the table and select “Update Metadata”.
For successful backup and recovery, first of all, you need good preparation based on a reliable organization and a good understanding of the SAS architecture. Therefore, the cooperation of the metadata administrator and the administrator of the corresponding servers is necessary.