ArGest Backup User Guide

  1. Home
  2. Docs
  3. ArGest Backup User Guide
  4. Installation, Licensing, QuickStart
  5. Special Considerations for Library Use

Special Considerations for Library Use

If you have a library attached to your ArGest Backup system, you will be prompted to scan the library hardware the first time ArGest Backup is run or any time that you add or remove tape hardware to the system. Since you have the option of connecting 2 tape devices to your ArGest Backup system, this operation is required so that ArGest Backup will know which physical tape drive is located within the library.

Library Scan Notice Dialog

As indicated in the dialog, please make sure that all tape drives are empty and that there is a data tape located in the first slot on your library. ArGest Backup will inform you of its progress during the scan.

Additionally, it is important that the library be placed into “Random” or “Automatic” mode for proper operation with ArGest Backup. All library bundles shipped from TOLSI Group have this set by default. For other library vendors, please check your library documentation or contact the vendor for information on how to access this setting.

Make Sure the Library is Ready

During the scan, ArGest Backup loads a data tape from the first slot in the library to each library drive in turn (if more than 1). Once the drive(s) are identified, the tape is returned to the slot.

Library Scan Progress Dialogs

Once the scan is completed, you will be prompted to create your library destinations for archival use.

Initial Library Destination Dialog

Because ArGest Backup treats a collection of tapes in a library as a “destination”, you need to assign slots to a destination before you can use your library for archive operations. A destination can consist of a single slot or all of the slots within your library. The only limitation is that ArGest Backup destinations MUST be made of contiguous slots and should not overlap.

Additionally, when dealing with the tapes within a destination, you MUST handle all tapes in the destination as a single set and not handle the tapes as separate entities. Therefore, when dealing with the tapes in a destination, you must remove and replace all tapes in the assigned slots to change or reuse the destination. You should never remove “some” of the tapes in a destination.

If you need to modify the slots assigned to a destination after it has been used, it is also very important that you change the tape(s) in the destination as the slot handling will change and confusion over the media used could result in tape handling issues for the humans involved.

We also do not recommend using perpetual appending of incremental data to a library destination as you will eventually end up needing to replace the media within the destination. The current version of ArGest Backup will allow you to append data to a typeset in a destination as long as the current operations have not exceeded the capacity of the original media within the destination. Once operations to a destination’s typeset have exceeded the capacity of the tapes that are originally loaded, ArGest Backup will no longer allow you to append to members of that typeset. If you require this type of operation, our BRU Server solution is designed specifically to support it.

To put it simply, once you define a ArGest Backup library destination, treat it as one tape. If you must change the destination’s slot assignments, remove any existing media and replace them with fresh tapes. Do not develop a backup or archival scenario that assumes you will be able to append to a destination’s tapes forever.

!! Removing a portion the tapes from a destination’s assigned slots will confuse ArGest Backup’s tape handling logic and potentially result in unexpected overwriting of data on tapes within the destination.

Library Destination Manager

When defining a destination, Give consideration to the amount of data that will be written to the destination as a whole. For example, if you are using an LTO-4 device, the tapes are rated for 800GB per tape. If you determine that you will be backing up 2TB of data, you should allocate 3 tapes to the destination. If you have the time, you can get a closer determination of the number of tapes by running the full backup of the data to a destination consisting of 3 tapes. ArGest Backup will tell you how many tapes were used for the actual backup.

Since there is no way to estimate the level of compression for a given data selection, it is best to only use the native capacity when determining the number of slots to assign to a destination. For information on the native capacity of each tape type, please refer to the performance table previous chapter of this manual.