Dell PowerVault TL4000 - Manual (Page 166)

chosen for the reserved slot containing the cleaning cartridge. As with a library
with a single logical library, this slot is the last physical slot in the library (top
right magazine, uppermost rear slot).
Note: Configure the required number of reserved slots prior to enabling Auto
Clean.
To reserve a cleaning slot, follow these steps.
v To reserve slots in your library, go to the Web User Interface at “Choosing
General Library Settings” on page 4-24 or the Operator Control Panel at
“Configure: Library” on page 5-20 to get directions on reducing the Active slot
count.
5-68 Dell PowerVault TL2000 Tape Library and TL4000 Tape Library User's Guide