Exabyte EXB-480 Tape Drive
The Exabyte EXB-480 Tape Drive is a full-featured tape drive and carousel management unit. It features 8 cartridges/magazines, of which each can hold 10 tapes. A robotic arm is used to move tapes to the 4 tape drives. There are also two special slots: the EE (entry/exit) slot, which allows for one tape to be inserted/removed from the unit without opening the door, and the cleaning slot, where one cleaning tape is kept.
For more specific information on how to use the carousel and tape drives, look at the article for what server it is connected to. As of the time of this writing, it is connected to emperor.
Two Exabytes were donated to the lab in early 2005 by a TJ alum from Fannie Mae. Included with the donation were a large amount of data and cleaning tapes, two keys to open the secured door, and a large amount of barcode labels used for the inventory functionality of the unit. We received a third exabyte-like unit in Spring 2009.
- Tape type: Exabyte "Mammoth" tapes
- Maximum Library Capacity: 1638.4 GB native/uncompressed (20 GB per tape, 80 tapes)
- Transfer Rate: 42 GB/hr native/uncompressed
- Interface: LCD user control, High Voltage Differential (HVD or Differential) SCSI, serial user control.
Usage and Notes
- The robotic arm can be controlled by the
mtxcommand (found as a Debian package with the same name).
- The door can only be opened at certain times with the supplied flat key. Once it is closed after it has been open, the system assumes a change has occurred in tape arrangement and will proceed to reinventory all the tapes. This usually takes a while, so if your intention was to insert a small number of tapes, the EE slot would be a better alternative.
- The drives need to be cleaned periodically by using the cleaning tape. The LCD interface will indicate when cleaning is necessary. Also, if reading from the tapes gives errors and syslog reports something like "Additional sense: Recorded entity not found", the drive most likely needs to be cleaned.
Explanation of Elements
(As output by 'mtx status')
- Data Transfer Element 0-4: The tape drives, used for reading/writing tape data. After 'mtx load'ing a tape, the tape device can be accessed at /dev/stX. You must issue a 'mt offline' on the appropriate /dev/stX device before performing a 'mtx unload' on the tape.
- Storage Element 1: A non-moving slot, where the cleaning tape is usually kept.
- Storage Element 2-81: All normal tape storage locations, located on the main drum.
- Storage Element 82: The IMPORT/EXPORT slot. You probably should not explicitly put tapes here using mtx (as you cannot remove tapes from this slot using mtx), but instead is only used when inserting or removing tapes from the EE slot.