Tina, the info above is correct. The North Fork permit quota (trail J34) is 6 reservable, and 4 held back for walk-in requests.

The 4 walk-ins become available at 11 AM the day before the entry date at the Visitor Center south of Lone Pine. If there are any no-shows in the 6 reserved, they become available at 11 AM on THE entry date.

There just aren't many permits given out for that route for overnighters, and I doubt you will find any cancellations online.

Now, if you can't get an overnight permit, you might like to try for a day hike -- Russell should be quite doable as a day hike, if you get started just before dawn. To enter the Whitney Zone for a day hike, whether you are going up the Main Mt Whitney Trail OR the North Fork to climb Mt Russell, you need the same Mt Whitney day hike permit. There are usually plenty of no-shows available at 2 PM the day before the hike, but you might even inquire/obtain those at 11 AM or earlier.