5 1 0:Media Strategy
Overview
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An effective media strategy is based on evaluation of data requirements, considering volume and frequency of backups, and assessment of suitable media types, balancing backup requirements, performance considerations, and budget constraints. Using a mix of media types, such as disks for short-term storage and tapes for long-term archiving, can efficiently address varying backup demands and resource availability.
SEP sesam provides a range of features to help tailor a media strategy to individual requirements. Media is organized into media pools, which define retention policies based on backup types, retention needs, and usage patterns. This ensures that storage is used effectively and enables management of data throughout its lifecycle.
Additionally, SEP sesam supports compression and deduplication to enhance storage efficiency and maintain optimal performance. It offers tools for optimizing media utilization and rotation, ensuring consistent and efficient operation. Monitoring and reporting features allow users to adapt their media strategy to changing data requirements, usage patterns, and storage capacity, ensuring the strategy remains effective over time.
Key features
- Efficient media management enables you to handle and organize large quantities of media of different types.
- Write protection keeps your data from being accidentally overwritten.
- Spare media pools prevent failed backups due to missing media.
- Media tracking records and monitors all media details, including used capacity, End of Lifetime (EOL), and user-defined write protection.
- Barcode support on loaders improves media handling and tracking.
Media organization
Media in SEP sesam is any physical or digital storage medium used to store backup data. The term medium describes a data carrier to which data can be written and can include a variety of formats:
- Tape media: Physical tapes used for storing large volumes of data in tape libraries.
- Disk media: Hard drives or other disk-based storage devices (datastores) used for faster access and retrieval of backup data.
- Cloud storage: Online storage services that store data on remote servers accessed via the internet.
To prepare tape media (tape cartridges, removable drives, etc.) for SEP sesam, they must be initialized. The initialization process places a medium into a media pool, generates a unique media label, and writes it to the media. The unique media label is stored in the SEP sesam database and is used for identifying SEP sesam media during backups and restores.
Media pools
In SEP sesam, media is organized into media pools, which are groups of media of the same type used for backups. Media pools form the basis for building a backup strategy. Each media pool represents a set of media designated for a specific purpose. Media pools are configured differently depending on whether they are for tape media or data store (for backup to disk storage).
To optimize backup performance, SEP sesam ensures that media is fully utilized and written to until the End of Media (EOM) is reached. When a tape is full, SEP sesam automatically requests a new one from the corresponding media pool. Media utilization and reuse are regulated by defining retention time for media pools, setting write-protection in a media archive, modifying the lock date of media to exceed the media EOL, and configuring media events in SEPuler.
For more details, see Media Pools.
Failover media pools
A failover media pool ensures the continuity of backup operations if the primary media pool is unavailable. Any configured media pool can be designated as a failover media pool. When the current media pool cannot be accessed, the failover media pool is automatically used instead, providing the necessary media for the backup process. This mechanism enhances reliability and prevents interruptions in the backup schedule, ensuring that backup tasks are completed as planned.
For more details, see Configuring a Media Pool.
Spare pools
A spare media pool is a media pool that you can configure to allow the sharing of spare tape media across media pools. Spare pools are used by media events when the primary media pool runs out of media or the media is not available. Spare media are automatically allocated to the active media pool, preventing backup interruptions, eliminating the need for administrator intervention, and enhancing overall system reliability. Moving spare media to the working pools dynamically increases media pool size, depending on the amount of data being backed up.
You can create a compatible spare pool of free media for each drive type. The name of a spare pool must begin with SPARE_. For details, see Configuring a Media Pool – Spare Pool. For more information on tape management operations, see Tape Management.
Media utilization and reuse
SEP sesam optimizes the use of available media to maintain an efficient backup system. Media use and reuse of media are controlled by retention time, determining how long media is write-protected and cannot be reused. During this period, the data on the media is protected and cannot be overwritten.
After the retention time expires, media becomes available for reuse. SEP sesam employs the GET_OLDEST policy to manage this process. This policy ensures that the media with the oldest expiration date is used first for new backups.
Users have the option to override automatic process by locking media for an indefinite amount of time (setting write protection). Locked media is not reused, even if the retention time has expired. This feature allows users to retain critical data on specific media without the risk of it being overwritten or reused.
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| The modified EOL is also recorded in the main log and can be generated for audit trail purposes, see Audit Logging. |
Retention time
When configuring SEP sesam environment, you set up media pools and define the retention time. The media pool retention time is specified in days and defines how long the backed up data remains protected after it has been written to the media. This is called the expiration date of a saveset - EOL (End of Lifetime). The retention period starts on the day a saveset is written to the media and lasts for the period defined by the media pool retention time. When the protection expires, SEP sesam can re-use the media for backups again.
For disk media, the reuse of storage space is controlled by the saveset's End of Life (EOL). Once the EOL for a saveset expires, the storage space can be reused. For tape media, the media EOL is determined by the longest saveset EOL on that tape. Unless the tape locked or write-protected, it can be reused after the EOL of all savesets on the tape has expired.
The storage space of a saveset can be reused when the following conditions are met:
- The saveset EOL has expired. If the saveset is stored on tape, the media EOL must have expired.
- The saveset must not be write-protected (locked).
- There must be no other savesets that depend on this saveset. You can override this condition by allowing the EOL for the entire backup chain to expire, which will delete backup data for all related savesets.
For more information, see Automatic Retention (EOL) Management.
GET_OLDEST policy
The GET_OLDEST policy in SEP sesam determines which media to use next for backups. It ensures that media is reused in an efficient and organized manner, preserving data on the media for as long as possible. This strategy is always used when a single media pool is associated with a media event or schedule.
The GET_OLDEST policy prioritizes media for reuse based on the following factors:
- Expired EOL: The policy first looks for media with expired EOL. For tape media, the EOL of all savesets stored on the tape must have expired.
- Oldest media: SEP sesam prioritizes the media with expired EOL, starting with the oldest expired EOL. This ensures that data is retained for the longest possible time and to reuse space the oldest data is deleted first.
- Write protection: Only media that is not write-protected (locked) is selected for reuse.
By following these criteria, the GET_OLDEST policy ensures that storage resources are used effectively, reducing waste and maintaining an orderly rotation of media.
Media management and administration
SEP sesam automatically handles different media management tasks. In situations such as unavailable media at the start of a backup or reaching the end of media (EOM) during data transfer, SEP sesam creates an internal media event to resolve the situation. Internal events determine the next media to be used to successfully complete data management tasks. If no other media events are configured in the schedule, only internal media events are executed.
User-defined media events allow you to perform specific actions related to media management and can be configured using the SEP sesam UI. These events are automatically activated by SEPuler, the SEP sesam scheduling component.
When a media event contains a specific label, the system will attempt to find it and load it into a drive. The autoloader magazine must be accessible to SEP sesam, otherwise the task will be cancelled.
For more details, refer to Creating a Media Event.
Archive adjustment
Archive adjustment is a process that ensures consistency between the media in a loader, like a tape library, and the SEP sesam media archive database. It compares the inventory information of the loader with the SEP sesam database and updates the database with the latest details from the scanned device. This synchronization process must be performed whenever there are changes in the loader, such as inserting new media or used media that haven't been initialized by SEP sesam. Running archive adjustment is important to identify any unrecognized tapes and maintain accurate inventory records.
You can perform archive adjustment manually (in the GUI under Main Selection -> Components -> Loader -> Archive Adjustment ) or create a special media event for it and schedule it to run automatically at specified intervals.
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| When selecting the option Archive Adjustment, make sure that the autoloader being realigned is selected in the GUI window, i.e. that the target device is at the top of the adjustment task. If you use the command line, the task must include the name of the target autoloader or tape device. |
For more details, see Setting up Archive Adjustment.
See also
Backup Strategy – Media Pools – Configuring a Media Pool – Tape Management – Creating a Media Event – Automatic Retention (EOL) Management – Setting up Archive Adjustment