Overview
The Great Library concept was realised in Second Life by noted Jedi Master and renowned Galactic Scholar Master Marcus Moreau. Its purpose was to gather together information and place it under a single roof, so that all in the Galaxy could benefit from it. As such, the Great Library therefore is non-partisan and all factions from Star Wars (and from the wider Second Life) are welcome, despite being maintained by the Jedi.
Most of the Libraries and Archives around the SWRP Galaxy have material from the Great Library, some are in fact near-facsimilies.
Locations
The Great Library has been locatated in many different places since its conception, but the main two locations were Anoth and the current location, Ossus.
Anoth
The Great Library of Anoth
The Great Library of Anoth was the first realisation of the concept, and was situated in the Mars Region, on the land Marcus Moreau originally had as his Anoth Station. Those who remember this startling edifice will recall how it seemed to go up for ever into the sky and the perma-darkness of the sim, pierced by the soft glow of the archives. Many of the senior SWRPers around today will have learned their lore from this wonderful building, and therefore it is remembered even though it no longer exists, having been pulled down in late 2007 when the collection moved to Ossus.
Ossus
The Great Library of Ossus
In the Canon, the Great Library was originally based on the Jedi world of Ossus. Master Moreau therefore approached the Jedi Guardians of the Peace about moving his collection there in 2007, and his friendship with the sim owner Leonardis Mission allowed this to go ahead. A previously-unused island in the sim was given over to the purpose of housing the new building, and Master Moreau built it entirely himself, although the landscaping and immersion was done by Leonardis. Master Moreau moved his great collection of work over from Anoth in the third-quarter of 2007 and the Great Library of Ossus remains the largest in-world collection of Star Wars lore.
Other locations
The Great Library was also at one point located in several other planets around the Galaxy after its departure from Anoth. Master Moreau formed the now-defunct Great Library Network, which allowed there to be two main library branches (at Ossus and Telos IV) and much smaller sub-branches each its own subspeciality topic, and linked into the Network via a computer panel. These other locations included: Telos IV, Kashyyyk, Little Mos Eisley and Taris.
The Network is no longer operational, and the Great Library is now solely based on Ossus, with its own teleportation location in Search.
Reference
Great Jedi Library in Wookiepedia.