5 1 0:Media pools

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Welcome to the latest SEP sesam documentation version 5.1.0 Apollon. For previous documentation version(s), check documentation archive.

Media pools

A media pool is a group of media of the same type that you use for backups. You can have different types of media pools for different types of backup data, backup sources (e.g., file backup, DB backup), or drive types. How you configure a media pool depends on the type of storage device you are using, i.e. tape or disk storage. With loaders, you set up a media pool to be used for backups directly to tapes. For backups to disks or cloud (disk storage, S3 cloud storage), you have to set up a data store first, but still create one or more dedicated media pools for it. You can also configure a spare pool as an additional source of media of the same type that can be used if all tape media in a pool are in use. For details, see Configuring a Media Pool.

Media labels

Once a media pool is configured, SEP sesam automatically provides each media with a unique media label during initialization. The media labels are stored in the SEP sesam database. The labels consist of the pool name (e.g., Day_, Week_, Month_) and a 5-digit number assigned by SEP sesam within the pool. For example, if the media pool name is LTO_month, the media label for media in that pool would consist of the prefix LTO_month followed by an ascending number, e.g., 00001 – the first media label would be LTO_month00001. The next medium would have the media label LTO_month00002, and so on.

Data stores

While media pools are a traditional way of organizing data storage and are typically used for backups directly to tapes, SEP sesam uses a data store for backups to disks (disk storage). Even though the data is still primarily backed up to a media pool, a data store is used underneath to save the data directly to one or more configured storage locations – in the file system. For details, see Data Stores.

Backup strategy

Media pools are the basis for building a backup strategy. Each media pool represents a set of media designated for a specific purpose. For example, media pools can be created and managed for workdays, weekends, specific locations, specific types, databases, etc.

It is possible to configure special GFS media pools for storing data on tape according to the classic GFS (Grandfather-Father-Son) backup rotation strategy. However, there are several backup strategies to protect your environment that can be easily implemented with SEP sesam. For more information, see Backup Strategy Best Practices and GFS Backup Retention Strategy.

You can create a new media pool from Main Selection -> Components -> Media Pools -> New Media Pool. For details, see Configuring a Media Pool.

Media pool properties

Double-clicking a media pool opens its properties, where you can modify the media pool's settings. The media pool properties differ depending on the media pool type (for tape or disk storage). The following example shows the properties for the media pool used for backups on tapes, with two additional tabs: Readability Check and Options.

In the case of LTO tapes, an additional Encryption tab is displayed where you can enable LTO encryption of tape drives at the media pool level. For details, see LTO Encryption.

  • Name: The name of a media pool; it must not end with five numbers because this form is used for media labeling.
  • Description: Optional description of the pool, e.g., Monthly backup.
  • Drive Group: Selection of the drive group to which a media pool is attached (e.g, Tape_Drives, RDS_LTO_Dives, etc.).
  • Type: If configured, the media pool type (e.g., clone) is displayed.
  • Retention time [days]: The time period for which all media in the respective media pool are protected after the data has been written to the media, thus preserving the savesets and keeping them available for restore. The retention time period starts with the date a saveset is written to the media and lasts for the period defined by the media pool's retention time (in days). The expiration date of the retention time is the EOL of the saveset. When a saveset is stored on tape, every stored saveset has its own saveset EOL; however, the tape expiration date is the maximum retention time (the longest EOL) identified on the tape. For details, see Automatic Retention (EOL) Management.
  • Failover media pool: Select a media pool to be used instead if this one is not available.
  • Set media pool inactive: If selected, a media pool is deactivated, so it is not available for use.
  • Note
    In the case of a clone media pool, the option Set media pool inactive controls not only whether a media pool is available for use, but consequently whether the upload – synchronization with the S3 cloud - is performed. If you deactivate a clone media pool by selecting the option Set media pool inactive, the data is no longer synchronized with the S3 cloud. For details, see S3 Cloud Replication.

Readability Check

This is a process that checks the readability of the data on the tape and its structure, and ensures that the backup sets on the tape are recorded in the database and vice versa. The results are displayed in the log.

Readability check is configured by a special media event. For details, see Creating a Media Event.

  • Readability check limit [days]: By default, the value is 0 (zero) and readability check is disabled. If a number > 0 is set, a medium is checked after the specified number of days and marked with the status Readability check required. Readability check can only be applied if a Media EOL has not expired and is not applicable for EOL-free media. For details, see Configuring a Readability Check.
  • Expiration of read check overdue [days]: The number of days after which a readability check is overdue. It is calculated based on the readability check limit [days] and the value of expiration overdue.
  • Repeat rate for readability check [times]: If Unlimited is selected, the media are checked according to the specified frequency. If Execute is selected, the check is repeated as many times as specified.
To perform the readability check, you have to set up a schedule and link a media event to it. For details, see Creating a Media Event.


You can configure a number of options (depending on your strategy) to enable media sharing across media pools.

  • May use empty, foreign media: SEP sesam will use unknown or blank tapes for the backup if no tapes are available in the respective pool. (A newly purchased media that has never been used is also considered 'unknown' in this context).
  • May use EOL free media: Media with expired EOL from the same media pool can be used for backup. If this option is not selected, the use of a specific medium can be forced.
  • May use SPARE media: If there is no media (tapes) available in the target media pool, but the SPARE_ media pool is configured, SEP sesam automatically uses the media from the SPARE pool.
  • May use media from another pool: SEP sesam uses available tapes from other media pools if no tapes are available in the target media pool.
  • Another media pool may use media from this pool: A media pool that has run out of its own tapes can use the available tapes from this media pool.
  • Close current backup tape before initializing new one: When you change to a new tape in this pool, the tape that is currently in use in this pool will be closed before a new one is initialized. With this option, the tape will get closed before it is offloaded from the tape drive, so that no more data can be appended to this tape.

If the data on the tapes is no longer needed, the metadata on the tape media in the media pools can be removed:

  • Delete all metadata of tape media, once the tape becomes EOL free: Data on tapes can only be deleted when their EOL has expired. If you enable this option, the metadata of tapes that are no longer write-protected will be deleted.
  • Delete all metadata of tape media and re-initialize the tape, once the tape becomes EOL free: Enabling this option erases all metadata on the tape media and reinitializes the tape (provided the tape is available to SEP sesam) by loading the tape into a drive and physically erasing it, thus removing access to all existing data on the tape.
Media sharing strategies are based on acquiring media from the different pools, which means that such media are transferred from the original to the respective pool, and are no longer available in the source pool. You should take this into account when planning your media strategy. For details, see Media Strategy.


You can specify the required permissions (ACLs) for the media pool under the new Permissions tab. For details, see Using Access Control Lists.

See also

Media Strategy - Tape Management - Configuring a Media Pool

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