Louisiana is under a state of emergency.
Louisiana Gov. Bobby Jindal on Wednesday declared a state of emergency and activated the National Guard. Jindal said 3,000 troops will be deployed a day in advance of the storm's expected landfall. An additional 2,000 troops could be called up.
The state has some 500,000 pre-made meals and bottles of water ready to distribute.
"We're getting everything in place just in case," said Veronica Mosgrove, spokeswoman for the Louisiana's Governor's Office of Homeland Security and Emergency Preparedness. "We're taking (Gustav) very seriously."
Katrina hit New Orleans on Aug. 29, 2005, as a Category 3 hurricane. The storm surge breached the city's levees, flooding 80 percent of New Orleans with up to 15 feet of water. Hundreds died statewide. The storm also devastated portions of coastal Mississippi.
The Federal Emergency Management Agency, which was criticized for its slow response to Katrina, has more than 2.4 million liters of water, four million meals, 478 emergency generators, 141 truckloads of tarps and 267 truckloads of blankets and cots to be distributed in the Gulf states.
The agency also has readied nine field medical stations, each of which has 250 beds.
If Gustav strengthens to at least a Category 3 when it comes within 72 hours of the city, New Orleans officials plan to order a mandatory evacuation, said David Baird of the city's homeland security and emergency preparedness office.