At the formation of the SLDF:
First and Second Reserve Corps
The two Reserve Corps were organized from among the soldiers of the new SLDF who opted to retire from active service but that still wanted to serve the Star League.
Within the First Reserve Corps, the Twenty-fifth Division was headquartered in the Lyran Commonwealth, the Twenty-sixth in
the Draconis Combine, and the Twenty-seventh Royal Division in the Terran Hegemony. The Second Reserve Corps’ Twenty-Eighth Division was the Free Worlds League reserve, the Twenty-ninth the Capellan reserve, and the Thirtieth was the Federated Suns reserve division.
By the time we get to the Amaris Crisis we have references to the SLDF Reserve (especially the openeing fiction of LoT1) and New Dallas.
Reserve Command
CO: General Abhinav Hammond
Overseeing both planetary garrisons and demobilized troops and their equipment, Reserve Command is a resource used to bolster the active commands in times of need. Members of the reserve are expected to attend a two-week recertification exercise each year, for which they were paid a stipend. Some commands (such as BattleMech and fighter forces) require bi-monthly weekend exercises. Reserve Command is easily the largest component of the SLDF, even if it rarely earns face time in media reports. Every Star League member-world hosts some form of Reserve Command presence, from small battalion-size training and security formations on the sparselypopulated Periphery worlds or new colonies to standing armor and infantry divisions on member-state core worlds. The large, less-trained mass of single-term enlisted SLDF soldiers often find duty in infantry
or armor regiments, brigades and divisions in Reserve Command.
We have the Reserve Fleet:
RESERVE FLEET
While the SLDF’s active fleet comprised some 2,250 vessels, this represents only seventy percent of its total strength. The remaining vessels, around a thousand ships, are held in the Reserve, mothballed to save on operating costs or else undergoing periodic refits. In time of conflict these vessels are reactivated and used to bolster the Star League Navy. Unlike the ships of Garrison Fleet, the Reserve has only caretaker crews on-board or nearby on fleet anchorage stations. The Reserve is largely spread across the Hegemony, though small pockets are cached near central worlds of each military region to provide a ready source of replenishment should combat occur. SLDF SB
Obviously the Reserve must have been huge - but what happened to it? The Hegemony Reserve units fought and mostly died. The formations in the Member States never mobilized as formed units. I can see large numbers becoming individual replacements for the Regular Army although the loss of so many units in the Periphery Campaign argues that either they took much worse casulaties or few Reservists came forward.
