Minimizing Elevator and PTP Activity

There are several things you can do to minimize elevator and PTP activity.

Table C-2 Recommendations to Minimize Elevator and PTP Activity

Action	Recommendation
Mounting cartridges	Whenever possible, when mounting a tape, use cartridges and tape drives that are in the same LSM. LSM refers to a single rail within the SL8500 library. Each SL8500 contains 4 LSMs.
Using float	Take advantage of the ACSLS “float" option (enabled by default by ACSLS) by maintaining some free cells within each LSM. Cartridge float is a feature that allows ACSLS to place a dismounted tape cartridge in an empty slot in the same LSM or a closer LSM to the tape drive if the tape originally came from a different LSM using a pass-thru operation. When cartridges are dismounted, ACSLS tries to avoid elevator (pass-thru) activity among LSMs by assigning a new home cell whenever the cartridges' old home cell is in a different LSM. ACSLS attempts to put the cartridge away: in the same LSM as the tape drive from which it was dismounted or to the closest LSM (with free storage cells) to the drive
Entering cartridges	Enter cartridges into an LSM that has compatible tape drives for the media being entered. Example: You have only LTO drives on LSMs 2 and 3, and you want the LTO cartridges to be located in these LSMs. When entering these cartridges, you should place them in the CAP magazines adjacent to LSMs 2 and 3. ACSLS then makes every effort to put the cartridges in the LSM that is adjacent to that CAP magazine.
Scratch cartridges	Make sure that scratch cartridges are available in sufficient quantity in each LSM where they will be used. For an SL8500, this means having scratch cartridges available on each rail (LSM) of the library.
Free cells	Make sure that there are adequate free cells in each LSM.