Disable Blog during domain move

Not that I know of because the old blog will persist until the DNS repoints unless you actually remove it. I usually see people post a message saying things are changing and to look out for a message (which you write on the new blog) to say all is good.

So there is no way to prevent someone from posting a comment during the move?

If you take down the site at the same time you take the backup, yes otherwise no. The database can’t know what’s going on neither can the code.
Unless you tell people it’s moving they’ll not know so they’ll post.

If you can access your blog’s database through an admin tool such as phpMyAdmin, you can use the following query before your move to *lock* down commenting on all current posts this way:

UPDATE wp_posts SET comment_status = 'closed', ping_status = 'closed';

Then once the move is completed, change 'closed' to 'open' with a similar query. Note that the prefix on the posts table (wp_posts) may be different.

Running the query will work – I was hoping there was something in the Dashboard … maybe a future enhancement.

Thanks podz and Kafkaesqui for your help.