Ferment 3 gallon batches in 6 gallon ferementer?

I have a feeling this has been answered many of times. I just cant seem to search for the right thread. I am planning on making a barleywine but dont want to make a full 5 gallon batch. I would like to do 2.5/3gal batch as I just dont want to use up 2 cases of bottles for years. I brew enough to keep them in a cycle.

So I was wondering if I made a smaller batch would there be any problems with fermenting in a 6gallon bucket? Will the headspace cause any problems? Just curious. Thanks in advanced for any advice and any links you guys may add.

3 gallons will be fine in the primary. A 3 gallon barley wine, and most 3 gallon recipes in fact, will produce enough CO2 to fill the head space in the primary.
If you plan to use a secondary to age, i would reccomend finding a small carboy (But it sounds like your aging in bottles anyways.....)

No worries with 3 gallons in a 6 gallon vessel. There will be a nice, cozy blanket of CO2 on top of the fermenting beer.

thank you for your responses. I am going to do primary for 4 weeks, rack to secondary for 2 months. then bottle age for 6 months minimum. I will be on the look out for a smaller carboy.

Here are some. I have been meaning to buy two of them, so i can split a batch and dry hop with two different varieties as a flavor experiment.
http://www.midwestsupplies.com/3-gallon-glass-carboy.html

I don't see any problem with doing 3 gallons in a 6 gallon fermenter for the primary; in fact, I'm also brewing a party gyle 3 gallon barleywine batch this weekend and will be fermenting in a 5 gallon carboy. When you rack to secondary, especially if you're dry hopping, I would recommend purging the carboy/keg with CO2 if you have a tank. Oxidized hops = bad.