In Chapter 7 of "The Great Gatsby" Fitzgerald alludes to Trimalchio, a former slave in a narrative by Petronius who attained wealth and power through hard work and perseverance much like Gatsby's having attained wealth after a modest beginning. Because this Trimalchio gave lavish parties, Nick writes of Gatsby, "his career as Trimalchio was over"; this allusion suggests that the illusion of Gatsby--his "American Dream"--may be coming to an end.
In place of his servants, "an unfamiliar butler with a villainous face" greets Nick "in a dilatory, drudging way," and answers Nick's questions with rude monosyllables ("Nope," "Who?" "All right"). In reality, this "servant" is a man that the mentor of Gatsby, Wolfsheim, has recommended. Gatsby explains to Nick that Wolfsheim suggested that Gatsby use these people who would be discreet about Daisy's visitations: "I wanted somebody who wouldn't gossip." At these words, Nick reflects,
So the whole caravansary of servants had fallen like a house of cards at the disapproval in her [Daisy's] eyes.
The choice of the word caravansary, an inn for caravans in Persia, again suggests the allusion of Trimalchio,but now there is a somewhat satirtic tone attached to this allusion as Gatsby's dream, tainted with corruption of his mentors, begins to deteriorate in the intense heat of the summer and the passions of the characters which crescendo before their deterioration.
In a nutshell, Gatsby wants to make room for Daisy. He wants her to feel comfortable when she comes to his house. He knows they have to be discreet too, so the gossipy servants have to go.
As for the parties, Gatsby had been throwing them for all and sundry, hoping that Daisy would show up one evening. She never did, uninvited. Through Nick, his summer neighbor, Gatsby will get to see her again and again. The parties are no longer necessary.