4 4 3 Beefalo:Media pools
Media pool is a group of media of the same type that you use for backups. You may have different kind 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 the used storage device, i.e., tape or disk storage.
Once a media pool is configured SEP sesam automatically labels each medium with a unique media label during initialization. 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 name of the media pool is LTO_month, the media label for media in this pool consists of a prefix LTO_month, followed by an incrementing number, e.g., 00001 – first media label would be LTO_month00001. The next medium would have a media label LTO_month00002, and so on.
While media pools represent a conventional way of organizing data storage and are typically used for backing up directly to tapes, SEP sesam uses a data store for backing up 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 on one or several configured storage locations – into the file system. For details, see Data Stores.
Media pools are the base for building a backup strategy. Each media pool stands for a set of media, foreseen for a specific purpose. For example, media pools can be created and managed for work days, weekends, certain locations, certain types, databases, etc.
It is possible to configure special GFS media pools for storing a data to tape according to the GFS (Grandfather-Father-Son) retention strategy. For details, see GFS Backup Retention Strategy.
You can create a new media pool from Main Selection -> 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. In case of LTO tapes, additional Encryption tab is displayed where you can enable LTO encryption of tape drives on a media pool level. For details, see LTO Encryption.
- Name: The name of a media pool; it may 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 will be 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 data is written to the medium, 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 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 expiration date of the tape corresponds to the maximum retention time (the longest EOL) identified on it. For details, see Tape media EOL.
This is a process that checks the readability of data on tape and its structure, and ensures that the backup sets on tape are recorded in the database and vice versa. The results are shown 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 the readability check is switched off. If a number > 0 is set, a medium is checked after the specified number of days and marked by status Readability check required. Readability check can only be applied if a medium EOL has not expired and is not applicable for EOL-free media. For details, see Managing EOL.
- Expiration of read check overdue [days]: The number of days when a readability test will be 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 medium is checked according to the specified frequency. If Execute is selected, the check will be 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 special set of options (according to your strategy) to allow sharing of media across media pools.
- May use empty, foreign media: If there is no available media in the respective pool, SEP sesam will use unknown or blank media for backup.
- May use EOL free media: If selected, media with expired EOL from the same media pool can be used for backup. If not, the use of the specific medium can be forced.
- May use SPARE media: If no media (tapes) is available in the target media pool, but the media pool SPARE_ is configured, SEP sesam automatically uses the media from the SPARE pool.
- May use media from another pool: If selected, it allows the respective media pool to use available tapes of other media pools if there are no available tapes in the target media pool.
- Another media pool may use media from this pool: If selected, another media pool that runs out of its own tapes can use the available tapes from the respective media pool.
|Media sharing strategies are based on the acquisition of 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 be aware of this when planning your media strategy. For details, see Media Strategy.|